Specialerapporter og -abstracts

Effects of bioactive pharmaceuticals on aquatic and terrestrial invertebrates

Nielsen, Maria Sandbjerg, 03.04.2017

Abstract:
Human pharmaceuticals are found in increasing amounts in aquatic and terrestrial environments. They are discharged via wastewater and sludge, where they are often found in complex mixtures. The concentrations found for single substances in nature are typically in the ng/L - µg/L range. Previously, pharmaceuticals were not considered as possible toxicants that could exert an adverse effect in line with other xenobiotics. However, this has changed in recent years. Despite this, the knowledge about effects on non-target organisms caused by pharmaceuticals is still limited, and because of their bioactive nature they are suspected of exerting a potent effect. 

Pharmaceuticals acting on the human nervous system are suspected of exerting an effect on the behaviour of aquatic organisms. In this study it was investigated whether it was possible to develop an acute test that could detect effects on sublethal concentrations of pharmaceuticals. In a videotracking test the freshwater shrimp Gammarus pulex was exposed to increasing concentrations of the pharmaceuticals carbamazepine, citalopram, diclofenac, fluoxetine and ibuprofen to investigate the effect of pharmaceuticals on the activity level. Fluoxetine and ibuprofen was discarded for further testing since high concentrations were needed to exert an effect. The three remaining pharmaceuticals were tested as single substances and in a mixture test. A 28 day chronic reproduction test was also performed on the springtail Folsomia candida to examine the effect of the pharmaceuticals carbamazepine, citalopram and diclofenac on a soil dwelling organism. This was done for single substances and a mixture as well.

The results from the videotracking showed a significant decrease in the overall activity level for all substances as the concentrations increased. They also showed a significant difference between control treatments and treatments with pharmaceuticals in concentrations of 8, 8 and 50 mg/L for carbamazepine, diclofenac and citalopram respectively. The mixture test showed that the model did follow the principle of concentration addition, even though the expected EC50 showed a much higher activity level than expected. The videotracking also showed that the activity level of G. pulex decreased significantly from trial 1-5 and that the activity level in trial 5 in general decreased from August to December, as the winter approached. Furthermore, it was observed that the activity level was significantly higher in trial 1 than any of the following trials throughout the whole testing period.

The reproduction test showed that the reproduction decreased significantly for all substances as the concentration of pharmaceuticals increased. For carbamazepine, diclofenac and citalopram a significant difference in reproduction was found for concentrations of 25, 100 and 50 mg/kg respectively. For the mixture test, it was found that the model followed concentration addition. Testing at environmentally relevant concentrations did not reveal any effect for either the videotracking- or reproduction test.

Based on the findings, it cannot be concluded that the videotracking test can be used as an alternative for the classic acute tests at low environmentally relevant concentrations. It is therefore not considered likely that carbamazepine, diclofenac or citalopram will exert an effect on the activity level of G. pulex or the reproduction of F. candida in nature. The same applies to mixtures of the three pharmaceuticals. But because of the additive response showed by the mixture test, the possibility of a negative effect cannot be excluded, if several pharmaceuticals occur at the same time in low concentrations. Since pharmaceuticals often co-occur in nature, this should be investigated further.      

Anvendelse af GIS til analyse af vedanatomi i Calluna vulgaris

Hjorth, Hanne, 22.03.2017

Abstract:
I specialeprojektet undersøges muligheden for at anvende Geografiske Informationssystemer (GIS), som en effektiv metode til at registrere vedanatomiske ændringer i forbindelse med dendroøkologiske undersøgelser. Et pilotprojekt blev gennemført med henblik på at teste metodens evne til at afsløre effekterne af græsning på vedstrukturen hos Hedelyng, herunder ændringer i de dele af i plantens ledningsvæv, som er bestemmende for dens vand ledningsevne. Som udgangspunkt regnede vi med det kunne lade sig gøre at detektere disse ændringer ved hjælp af en 2D raster model i GIS. Hedelyng, Calluna vulgaris, er en almindeligt forekommende dværgbusk og udgør et dominerende element på heder som Danmark er forpligtiget til at vedligeholde. Vind Hede i Vestjylland blev udvalgt som undersøgelsesområde, fordi lyngen i visse områder bliver græsset hårdt af kronvildt, mens den i andre områder tættere på bebyggelse ligger næsten ugræsset hen. Digitale billeder af anatomiske snit blev underkastet en billedanalyse i ArcGIS®.  Relativt få signifikante forskelle blev fundet mellem henh. græsset og ugræsset lyng, hvilket kan skyldes at på lyngen Vind Hede havde været hårdt angrebet og afløvet af Lyngens Bladbille Lochmaea suturalis få år forinden. På trods af dette fravær af klare resultater viser afslører pilotprojektet med al tydelighed at GIS 2D raster er anvendelig til dendroøkologiske undersøgelser og der er mange muligheder for at udvikle metoden yderligere.

The effect of changing water level in streams on plant communities in riparian areas

Andersen, Chris Jesper, 09.03.2017

Abstract:
During the last 200 years rich fens in Denmark have experienced a massive decline, making it a threatened habitat due to various human activities, such as changes in the hydrology. Rich fens are classified as a particular valuable type of nature because of high species richness and many rare habitat specific species, and therefore the Danish government is committed by EU to protect and improve the current unfavourable conservation status of rich fens.

The objective of this master thesis was to examine three hypotheses stated as: 1) the hydrology and the nature quality will be different between rich fens, wet meadows, and reed beds; 2) a lowering of the stream water table resulting from either dredge cutting or deepening of streams will affect the hydrology in the adjacent riparian area; and 3) the parameters which define nature quality in rich fens will be negatively affected by a lowering of he stream water table. 

Plant species coverage data from 51 plots divided into 191 sub-plots on riparian areas along 10 medium sized stream reaches were available for this study. Additionally, stream water level and groundwater level in the riparian areas was measured on a monthly basis during one year (2010-2011). The nature type of the riparian plots was characterized as rich fen, wet meadow or reed bed. Models describing the behaviour of a range of vegetation parameters to changes in in ground water level were developed from this data set. Hydrologic models were used to describe the correlation between stream water level and riparian ground water level. Scenarios on the effect of dredge cutting and deepening of streams were calculated by linking the hydrological models to the vegetation models. 

The results from this study showed differences in both hydrology and nature quality between the three nature types, with highest water levels and species richness, and lowest nutrient levels in rich fens. Hydrologic scenarios showed that lowering the stream water table from both dredge cutting and deepening, resulted in significant lowering of the riparian water table. Using the specific size of changes in riparian water levels, the established vegetation models confirmed negative effects on all of the nature types from both dredge cutting and deepening of streams.

Linkages of hydrologic interactions between streams and riparian areas and specific effect on riparian vegetation from changing stream water table have not been examined earlier.

As stream hydrology is manipulated in many Danish streams, and water levels are lowered from dredge cutting and deepening, understanding the hydrologic interactions can be essential for the future conservation of rich fens. 

Are temporal changes in ringed seal (Pusa hispida) blubber thickness related to climate change and hunting?

Jensen, Lærke Najbjerg, 27.02.2017

Abstract:

The sea ice extent in the Arctic is decreasing dramatically due to anthropogenic climate change, and it has severe implications for the ringed seal (Pusa hispida), which depends on the sea ice for prey and reproduction. Changes in prey abundances, loss of food sources and increased competition with other species, are all expected effects of global climate change (GCC) and may lead to changes in blubber thickness maintenance. The present study aimed to determine if temporal trends could be detected in blubber thickness, and if these were related to GCC, for three different regions in Greenland; Thule (Avanersuaq) in Northwest Greenland, Disko Island (Qeqertarsuaq) on the West coast and Scoresbysund (Ittoqqortoormiit) on the East coast. Three GCC predictor variables were used; sea ice extent, sea surface temperatures and the Arctic Oscillation Index. Additionally, human hunting pressure was used as another predictor variable, because climate change also negatively impacts this. Significantly increasing linear temporal trends were found for the ringed seal populations of Disko Island and Thule in the periods 1994-2012 and 1998-2014, respectively, while there was no significant linear temporal trend for the Scoresbysund ringed seal population between 1986 and 2016. Akaike's Information Criterion (AIC) model selection highlighted the importance of regional variability, but sea ice extent seemed to be the overall most important variable for blubber thickness, while AO seemed to be the least important one. No direct relationship between hunting pressure and blubber thickness could be discerned. Why the blubber thickness has been increasing on the West coast and remained stagnant on the East coast, is being discussed in the present study, but no clear explanation was evident. Potential theories involve an increased prey base and possibly reproductive failure, both as a consequence of significant sea ice declines happening within the same period. The present study emphasises the need for population density estimates, as declines in ringed seal populations will have consequences for the Arctic food webs, the indigenous people, and the polar bears, who all depend on ringed seals.

Laboratory natural selection for heat tolerance in dry and humid environments in Drosophila

Hilmar, Emma S., 13.02.2017, Speciale

Innovation in teaching high school biology – using design-based research to investigate the field between goals in science education and innovation skills in a biomimicry learning activity.

Aude, Nanna Johanne, 24.01.2017

Abstract:

Despite the demand for integration of innovation in science education in high school, quite few examples are seen in practice, especially regarding biology education. The result being that it is still unknown how the field between goals in science education and innovational skills is formed when an instructional design is developed. This paper explains how an instructional program combining education in biology and innovation skills was developed, using the design-discipline biomimicry as a framework and design-based research to measure students engagement and academic achievement. The paper shows that it is possible to combine goals in biology education and innovation skills in the class program, yet the practical execution poses a number of challenges. The paper shows that there is a challenge with displacement between goals in science education and innovation skills. It also shows that the evaluation of a program in innovation should be of a formative nature.

Narrow-band high-frequency click communication in wild harbour porpoise

Sørensen, Pernille Meyer, 19.01.2017

Abstract:

Highly social delphinids employ a rich vocal repertoire of clicks, burst pulses and tonal sounds for echolocation and communication. Conversely, harbour porpoises (Phocoena phocoena), seen as largely solitary animals, only produce narrow-band high-frequency (NBHF) clicks with properties that appear poorly suited for communication. Nevertheless, it is likely that these small toothed whales, like other cetaceans, mediate critical social interactions such as mate choice and mother-calf contact with sound. Therefore, we tested the hypothesis that stereotyped NBHF click trains are used for communication via their repetition rate by deploying stereo sound and movement tags (DTAG3) on six wild porpoises in Danish waters for a total of 96 hours. The tagged animals produced frequent (up to 27min-1), high-repetition rate click train calls (N = 3,792) at high apparent output levels and in dense bouts with high redundancy. The calls can, based on their developing click rate, be classified in distinct categories similar to those observed from studies on acoustic communication in captive porpoises. Thus, wild porpoises may be much more social than previously assumed and their frequent social interactions are mediated by calls made of short, high rate click trains that likely encode information via the repetition rate of their stereotyped NBHF clicks.

Keywords: communication, narrow-band high-frequency clicks, harbour porpoise, Phocoena Phocoena call rate, high repetition rate click trains, mother-calf

 

 

Barrierer i dansk økologisk landbrug - Identifikation af biologiske og administrative barrierer for omlægning til økologisk jordbrug i Danmark

Jensen, Karoline Helms, 19.12.2016

Abstract:

The objective of this paper is to identify which administrative and biological barriers might exist towards the Danish farmers whom wish to convert their farms from conventional farming to organic farming. It is assumed that barriers towards the conversion into organic farming do exist. This assumption is based upon data showing that the acreage of the Danish organic production has yet to recover from the two recent periods of decline in 2003-2006 and 2013-2014. It is examined in the paper if such barriers are of a regional character or if they could be considered national.
An online questionnaire has been developed to procure the necessary data, from which these barriers might be identified. Based upon a previous agreement the questionnaire was distributed to 75 agriculturalists from firms within the agricultural consultancy sector. The participating firms are scattered across Denmark. The questionnaire consists of 33 questions seeking to uncover which barriers the agriculturalists perceive to exist towards the conversion into organic farming. 45 agriculturalists answered and returned the questionnaire and it is these answers which form the dataset of this paper.
The paper explores whether the respondents deem that economic factors has an influence on the Danish farmers when they consider the possibility of converting into organic farming. The results show Indications of a strong correlation between the economic factors and the farmers’ readiness to convert into organic farming. Three barriers towards conversion into organic farming has been found in this paper. One of the identified barriers concerns the current rules and regulations regarding manuring which organic farmers are obliged to abide by. It is also identified that the availability of organic manure poses a barrier towards those organic farms without organic livestock. The last barrier identified in the paper concerns the current options of weed control available to organic farmers. In the paper, it is shown how these three barriers all influence the economic factors on some level and thereby the farmers’ readiness to convert into organic farming. The statistical significance of the results in this paper, has been tested by chi square tests and Fisher’s exact tests. No regional variations in barriers were found to be statistical significant.

Mare-foal interactions in Danish Warmblood and Icelandic Horses (Equus Caballus)

Negendahl, Natascha Stougaard Mandrup, 09.12.2016

Abstract:
The domestication and selective breeding of horses, has resulted in a lot of variation in size, color, behaviour etc. which have led to a lot of different horse breeds. Many previous studies have shown breed differences regarding maternal behaviour in other species (sheep, pigs, and cattle) but there are only a few studies on this subject concerning horses. Additional studies have also shown individual variation in maternal behaviour within a species (e.g. rats), and that maternal care does affect the development of the offspring. The aim of this study is to describe the variation in typical mare-foal interactions in two breeds of horses (Danish Warmblood and Icelandic horses) and to examine whether there is an effect of breed in these interactions. Secondly, the study aims to investigate the potential association in maternal care as shown in the first week post-partum and in week 9 post-partum. The study was done on 29 horses (Danish Warmblood n=15; Icelandic horses n=14). There were several breed differences, e.g. Danish Warmblood foals suckled more frequently in week 1 (P=0.021), whereas there was no breed difference in week 9 (P=0.56). The Danish Warmblood mares and foals vocalized more in week 1 than the Icelandic horses (freq. of nicker, P=0.017 for the foals and P<0.001 for the mares). There were also breed differences in the frequency of play behaviour, i.e. Icelandic foals showed more social play behaviour in week 1 (P=0.02), whereas Danish Warmblood showed a higher frequency of this type of play in week 9 (P=0.005). There was no breed difference in the frequency of aggression, nor in the distance between the mare and the foal. There was a positive correlation in frequency of suckling bouts between week 1 and week 9 (P=0.004). In conclusion, there seems to be a breed difference regarding some of the mare-foal interactions shown by the horses in this study. Likewise, it seems that there is a consistency of some of the mare-foal interactions in this study.

Keywords: Maternal behaviour; Breed differences; Horse; Mare-foal interactions; Individual differences

 

 

 

A sentient world

Nielsen, Mette Bech, 25.11.2016

Abstract:
How we treat animals highly reflect how we perceive their ability to feel suffering and well-being. Accordingly, to favour an ethical treatment of animals it is important to assess these abilities. The link between affective states and affective feelings is consciousness. An unconscious being cannot feel. Thus, the assessment of animal’s ability to feel must go through the study of consciousness. From the study of ‘contrastive analysis’ - comparing the functioning of conscious and unconscious information processes in humans – Baars (1988) proposed his now well-supported ‘Global Workspace’ (GW) theory of consciousness. According to GW theory, consciousness generates a mental scene constituted by information from multiple inputs that ‘broadcast’ information out to specialist modules throughout the brain, allowing for behavioural flexibility in response to
the perceived stimuli - in contrast to the rigidity of responses from unconscious processed stimuli. Also, conscious perceived stimuli constitute information to memory much faster than unconscious perceived stimuli.
By conducting a review of behavioural studies across chosen taxonomic groups in the animal kingdom, with focus on animal’s behavioural responses to affective cues, it is shown that all investigated species show a degree of behavioural flexibility and fast learning, consistent with GW theory of consciousness. Accordingly, the ability to feel seems to be widely distributed across the animal kingdom.


A Comparative Study of a Natural and two Man-made Lakes in a Brown Coal Area Consequences of massive anthropogenic disturbances of natural landscapes

Kristensen, Thomas Troels, 24.11.2016

Abstract:
Most environments have endured the effect of human expansion and exploitation, and will most likely feel it again or continue to be affected by it in the future. One feature of these anthropogenic landscapes are abandoned mining lakes which can be found all over the world today. These polluted fresh-water systems gradually develop towards conditions similar to that of natural lakes after excavation efforts ceased.
This study examined two mining lakes and one natural lake in Søby Brunkulslejer, Denmark, with the aim of describing the stages of development the mining lakes have undergone since their creation. This is the first study that combines sub-fossil cladoceran remains and sedimentological analysis of lake sediments that encompasses the environmental history of man-made mining lakes in Denmark.
Sediment cores from the three lakes has been analysed and dated using the standard lead-210 and caesium-137 method. Cladoceran species composition and abundance was analysed, and water content and Los on Ignition testing were used to determine the sedimentary composition through the cores.
A clear difference was found between the natural lake and the mining lakes. Within the development of the mining lakes 3 distinct stages were distinguished; Pre-lake, Transition-lake and Lake. Overall these stages are transferable across lakes, despite differences in the specific development in each lake. By examining the sedimentary composition and cladoceran remains in these novel systems, it is clear that several factors are involved in the lake's development, which ecologists and conservationists must take into account when studying and designing management strategies for this type of anthropogenic landscape.

 

 

Mere biodiversitet i Danmark: en undersøgelse af naturindholdet af nordjyske råstofgrave

Hvam, Patricia Vestergaard, 09.11.2016, Speciale

Landsdækkende undersøgelse af trusselsniveau fra danske terrestriske invasive plantearter

Nielsen, Steffen Larni, 25.10.2016

Abstract:
Mit speciale med titlen ”Landsdækkende undersøgelse af trusselsniveau fra danske terrestriske invasive plantearter” er udarbejdet som to artikler, som jeg tænker at indsende efter eksaminationen.

I artikel nummer et har jeg, via et spørgeskema, henvendt mig til botanikere inden for fem forskellige organisationsniveauer i Denmark; private botanikere, private naturkonsulenter, kommunale naturmedarbejdere, naturmedarbejdere i Naturstyrelsen og forskere ved danske universiteter med speciale i terrestrisk botanik. Respondenterne blev adspurgt, hvilke forvaltningsmæssige fokusområder, som er de anså for mest essentielle for at bevare dansk biodiversitet. Efterfølgende var der tre spørgsmål vedrørende, hvordan den nuværende danske indsats mod invasive arter forvaltning. Slutteligt var der to spørgsmål, omhandlende behovet for et handelsforbud og behovet for lovhjemmel til de værste invasive plantearter, hvis en forvaltningsplan mod arterne skal give mening og fungere. Spørgeskemaundersøgelsen gav mig 359 konkrete besvarelser. Invasive arter blev ikke vurderet til, at være det væsentligste fokusområde for at bevare dansk biodiversitet, det gjorde derimod eutrofiering og forvaltningstiltag imod fragmentering af naturarealerne. Undersøgelsen antyder videre, at der eksisterer en form for viden og kommunikations kløft imellem private konsulenter og kommunalt ansatte på en fløj og naturstyrelsen på den anden fløj. I forhold til de sidste to mere politiske spørgsmål, så viser resultatet bred enighed iblandt de danske botaniske eksperter, på tværs af forskellige organisations niveauer. Handelsforbud og lovgivning tilsvarende bekendtgørelsen for bekæmpelse af kæmpe bjørneklo, er minimus krav for at forvaltning af de værste invasive planter, skal kunne stoppe ydereligere spredning af disse arter.

I artikel nummer to, har jeg via samme ovennævnte spørgeskemaet indsamlet invasivarts vurderinger af de invasive terrestriske plantearter som er listet af Styrelsen for Vand- og Naturforvaltning. Undersøgelsen forholder sig både til et nationalt niveau og et kommunalt niveau. Den holdningsbaserede undersøgelse bliver sammenholdt med en frekvensbaseret analyse af registrerede fund af plantearterne i danske beskyttede naturområder. Registreringer er foretaget både af staten og kommunerne i henholdsvis DEVANO, NOVANA og Naturbeskyttelseslovens §3 områder. Det resulterede i 21667 artsregistreringer fordelt på 59 arter i de tre overvågningsprogrammer. For at give en indikation af frekvensen udenfor de naturbeskyttede områder, blev Atlas Flora Danica værket inddraget som reference. Frekvensanalyserne og invasivarts vurderinger blev delt op i to analyser; en som er rettet mod en nationale forvaltning af arterne, og en som er rettet mod en mere lokal orienteret forvaltning af arterne, med henblik på den kommunale forvaltning. Formålet er således at se på, om et nationalt fokus på arterne vil variere fra det fokus, den enkelte kommune bør have på arterne. Resultatet er, at nogle af de listede invasive arter er fundet så få gange, at en konkret kommunal forvaltning i alle kommuner ikke virker hensigtsmæssig. Dernæst viste arts distributions mønstrene, at visse af arterne grupperede sig meget forskelligt i landet. Hvormed resultatet, åbner for en diskussion af, om en differentiering i, hvilke kommuner som skal bekæmpe hvilke arter, måske kunne løfte forvaltningen af danske invasive arter. Undersøgelsen anfægter ligeledes det problematiske i, at have lange ukonkrete artslister over invasive arter som kommunerne burde bekæmpe. Hvorfor undersøgelsen specificerer de angivne arter ned til seks forvaltnings erkendelige arter som bør forvaltes i Danmark.

Evaluation of the expression of ina gene in single cells of Pseudomonas syringae R10.79 and its survival under simulated atmospheric conditions

Holm, Stine, 07.10.2016, speciale

Sæsonmæssig og substrat variation i, samt betydningsfulde miljøvariabler for den danske gødningsbillefauna

Møholt, Maja, 20.09.2016, speciale

Plasmacytoide dendritiske celler understøtter infektion med transmitterede HIV-1 stammer

Jensen, Kathrine Kjær, 09.09.2016

Abstract:
Formål: Formålet med dette studie var at undersøge infektioner med transmitterede HIV-1 stammer i humane pDC’er, samt at undersøge om pDC’er understøtter replikation og transmission af disse vira.
Metoder: Vi inficerede den humane pDC cellelinje GEN2.2 med fire forskellige transmitterede HIV-1 stammer og seks forskellige primære isolater/laboratorie-tilpassede HIV-1 arter, og høstede supernatanterne og cellerne efter 48, 72 og 96 timers infektion. Vi målte indholdet af p24 i supernatanterne ved ELISA og WB, mens cellerne blev analyseret for deres indhold af HIV-1 proteiner ved WB. Desuden blev infektionshyppigheden i GEN2.2 cellerne i kultur med eGFP-udtrykkende vira analyseret ved flowcytometri. Vi undersøgte ligeledes re-infektionsevnen af de inficerede GEN2.2 celler ved at tilsætte supernatanten fra de inficerede celler og selve de inficerede celler til TZM-bl celler og derefter måle luciferaseaktiviteten.

The Drivers of African Elephant (Loxodonta africana) Damage in the Maasai Mara, Kenya

Vestergaard, Emma Fitzmaurice, 09.09.2016

Abstract:

African savanna vegetation is changing, and becoming more woody in many areas. There can be many reasons for this change, but understanding it is important to predict future scenarios. Change in human lifestyles have meant that natural areas have been converted to agriculture or used for livestock grazing. The changing climate have affected the vegetation, especially the increase in CO2 levels. The increase has resulted in change in the growth rate of woody species, which could lead to more trees in the future. The natural fauna, such as the elephants also affect the vegetation. As they are ecosystem engineers, a change in their density and distribution could affect the local vegetation. Interestingly, the Maasai Mara has not had the same increase in woody vegetation of its savanna. The effect of these drivers might therefore not be as problematic in the near future, as it could be in other areas. The effects might be different in different areas, but will especially depend on human influences.

The use of allantoin to enhance asexual spore propagation in Porphyra umbilicalis

Nielsen, Lasse, Hornbek, 05.09.2016, speciale

Effekt af temperatur-variabilitet på transmissionen af Himasthla elongata fra først (Littorina littorea) og anden (Mytilus edulis) mellemvært

Gotliebsen, David Le Maire, 31.08.2016,

Abstract:
Blåmuslingen Mytilus edulis som findes både på blød- og hårdbund er en økosystemingeniør i kystzonens dyre- og plantesamfund på grund af dens evne til at monopolisere habitatet så vel som den kan fungere som substrat for andre organismer. Muslingen fungerer ofte som anden mellem-vært for trematoden Himasthla elongata, der transmitteres fra dens første mellem-vært den almindelige strandsnegl Littorina littorea. Himasthla elongata’s aktivitetsniveau og transmission reguleres af temperatur og derfor har temperaturen stor indflydelse på en afgørende del af dens livscyklus. I lyset af de seneste klimaforandring, er der blevet forsket i effekten af maksimum- og middeltemperatur på transmissionen af trematoder, men meget lidt vides om betydningen af temperatur variabilitet. Dette studie fandt at en øget temperaturvariabilitet fører til en øget transmissionsrate af H. elongata og derfor også en forøgelse af infektionsintensiteten i M. edulis. Konsekvenserne af en øget infektion med trematoder vil være reduceret produktion af byssus-tråde, hvilket ville gøre muslingerne mere sårbare overfor fysisk forstyrrelse og predation, og som en konsekvens, en øget mortalitetsrate i M. edulis bestanden. Da blåmuslingen fungerer som økosystemingeniør, kan den øgede mortalitet potentielt lede til en trofisk kaskade.

Aldersbestemmelse, vækst og gonadeudvikling af stillehavsøsters (Crassostrea gigas)

Vesterager, Emil, 26.08.2016

Abstract:
In this study of the Pacific oyster –Crassostrea gigas – oysters from an intertidal bed near Mandø in the Danish part of the Wadden Sea were examined. I have primarily focused on determining the age of the oysters, the growth of the oysters and the gonadal development of the oysters.
The density of oysters on the oyster bed is high and was estimated to approximately 550 per m2 in this study. This density equals 319 grams of shell free oyster dry mass per m2.
Three methods of age determination have been explored: i) Growth indicators in the hinge region of the oysters, ii) patterns of the oxygen isotope ratio (ẟ18O) embedded in calcium carbonate layers in the hinge region of the oysters and iii) cohort analysis. It was not possible to determine age of the oysters through patterns in the hinge region. Contrary to this, age determination of the oysters through analysis of ẟ18O samples from the hinge region was possible. Cohort analysis gave an indication of the age groups present on the bed.
The oldest oyster in the study was 23.5 cm long and with an estimated age of 10 years. Of the six oysters, which were age determined through analyzing ẟ18O samples from the hinge, five different age groups were found. The cohort analysis showed that a lot of age groups are represented and individuals bigger than 20 cm in length are expected to be +8 years old. Oysters bigger than 20 cm make up >1% of the population.
The growth pattern of the oysters was also examined in this study. Recruits grow from 8 mm to 37 mm during a year (from April). The mean growth of a group of oysters, which were labeled, was only 9.1 mm from April to December. The examinations show that the growth rates were higher for the small oysters compared to the bigger oysters. Over the first growth season the recruits had a 43 % chance of survival.
An investigation of the gonadal development of oysters shows that 40 % of the shell-free mass of the oysters is gonadal mass in June. The growth of gonadal tissue starts in the early summer and when the gonadal mass of the oysters was investigated on June 20th some gonads were mature and others were on the way to becoming so. In September the gonads of the oysters were empty and after the spawning, the gonadal tissue made up 15 % of the shell-free mass. Among the big oysters there were more females then males.

Environmental toxicity of Chemical Warfare Agents and their Degradation Products found in the Baltic Sea

Storgaard, Morten Swayne, 18.08.2016

Abstract:
2nd World War (WW) ended by the capitulation of Germany. Germany was disarmed by the Allied and Soviet forces and 65,000 tonnes of chemical munitions was dumped. The greatest dumpsite, the Bornholm Deep, received 11,000 of 13,000 active chemical warfare agents (CWAs). The environmental toxicity of the dumped CWAs and their degradation products have not until recently gained scientific interest and hence, there is a lack of knowledge. This thesis addresses this lack of knowledge by conducting a screening level persistence, bioaccumulation and toxicity (PBT) assessment, a MicrotoxTM bioluminescent inhibition test on Allivibrio fisheri and Spontaneous Locomotor Activity Changes on adult male zebrafish (Danio rerio) where 16, eight and one parent CWA and their degradation product were assessed, respectively. Four different mixtures were assessed in MicrotoxTM. Six out of eight effect concentrations (EC50) were obtained in the MicrotoxTM test with the Lewisite degradation product, 2-chlorovinylarsinic acid, being the most toxic with an EC50=31.20 µg/L. None of the four mixtures assessed demonstrated deviation from additivity predicted by concentration addition. The sulfur mustard gas degradation product, 1,4,5-oxadithiepane, was exposed to adult male zebrafish during a 14-days exposure period. The lowest treatment, with an actual concentration of 40.33 ± 2.91 µg/L, demonstrated highly altered behavior compared to the control group. For example, the average velocity was statistical significant lowered (ANOVA, p<0.05) and rest time duration during the measurement period was highly elevated in T1 (χ-squared=49.52, df=19 p<0.001) and T3 (χ-squared=38.05, df=19 p=0.006) compared to the control. 1,4,5-oxadithiepane demonstrated lethargic effects on the zebrafish locomotor behavior and this are discussed in relation to the cod (Gadus morhua).

Drone-based remote sensing of shrub dynamics in Arctic ecosystems

Madsen, Bjarke, 07.07.2016

Abstract:
This study presents a procedure for using drone-based remote sensing imagery in combination with climate and micro-topographic features to explain the dynamics of Arctic shrubs. These dynamics are examined in relation to climate change and attempt a linkage of different scales. The drone imagery was obtained from 20 regional study sites along the Arctic circle in Greenland. The data were afterwards classified with a random forest pixel-based classification, to estimate shrub cover at each site. NDVI trends from satellite datasets and climate variables were then associated with shrub cover and other drone-based data. Few NDVI trends could be recognized from the sites and no relationship to shrub cover could be concluded, even though multiple regression models, were able to explain shrub cover and NDVI observations. The resulting models contained variables of vegetation, micro-topography and macro-climate. By that, drone derived imagery offers a great assistance in understanding shrub dynamics of Arctic environments and can be considered a very resourceful tool in the future. 

Laboratorieøvelser som læringsaktivitet En analyse af aktivitet og samtale i laboratoriet samt de studerendes opfattelse af egen læring, i forbindelse med kurset Økofysiologi

Christensen, Sofie Schriver, 05.07.2016, speciale

Effect of low flow and eutrophication on leaf decomposition in streams

Jensen, Tinna Mia, 05.07.2016

Abstract:
The Danish landscape is filled with 64.000 km of streams that is highly influenced by their catchment areas. Because of that, the streams are stressed by the anthropogenic disturbance, which affect the stream ecosystem. Because of the large proportion of agricultural land in Denmark, some of the major stressors are nutrient enrichment and fine sediment addition in the streams, which is reinforced by reduction in discharge because of among others water abstraction for drinking water. These stressors could further be reinforced by the future climate change which implies heavier precipitation in the spring, autumn and winter and higher temperatures especially in the summer.

This paper aims to study the effect of reduced flow and because of that fine sediment deposition and eutrophication on leaf breakdown in a controlled environment. We manipulated flow conditions in 12 outdoor stream channels and added nutrients (N and P, in two levels) and fine sediment (two levels) to test the impact from these stressors on leaf litter decomposition in streams. Leaf packs with beech leaves were used to measure the leaf decomposition and macroinvertebrate samples were taken in order to establish their role in the leaf decomposition. An additional experiment was conducted in a laboratory setting to test the food choice of Gammarus pulex and to add further explanation to the result from the channels.

Low flow was found to decrease the leaf litter decomposition as well as the fine sediment deposition. The nutrient enrichment, however, did not affect leaf decomposition. The food choice experiment showed a tendency from G. pulex to prefer nutrient enriched leaves over leaves that had been buried in sediment but not significantly over leaves from the zero treatment, at least according to leaf mass loss.

The reduction in leaf decomposition under low flow might be explained by an increase in the physical boundary layer that slows down the nutrient and oxygen transportation from the water column to the microbes during decomposition. Additionally the sediment deposition creates a physical barrier for the macroinvertebrates to access the leaves and creates an even larger reduction in decomposition than the low flow. The explanation for the nutrient enrichment not affecting the decomposition might be the high concentration of nutrients in the channels with zero treatment and not a large fold of enrichment.

This study contributes to the understanding of the effects of the tree stressors on leaf decomposition in temperate streams and the stream ecosystem. It is important to take the results into account along with other studies which investigate the impact of these stressors on other parameters and mechanisms in streams when managing the freshwater ecosystems.

The effect of host genetics and rumen microbiome on milk fatty acids composition in Danish Holstein

Andersen, Nadia Pernille, 01.07.2016

Abstract:
Ruminant livestock are important sources of human food with milk production being a significant element. Feed degradation and milk production in ruminants are to some extent governed by the microbiome in the rumen. Host genetics has also been shown to have an effect on milk composition. To investigate how the microbiome in interaction with the host genetics affects the composition of fatty acids in the milk, both milk and rumen samples were collected. This data was used to calculate the heritability and microbility estimates. Microbility is an expression of the amount of the combined variation for a trait that is caused by microbial variation. The results showed some trends in the microbility and heritability between the different milk fatty acids. One tendency showed that high microbility is often coupled with a low heritability and vice versa. Another trend was that short and medium chain and saturated fatty acids tend to have lower microbility and higher heritability than unsaturated and long chain fatty acids. It looks as if it is beneficial to include microbial data in a linear model for milk fatty acids. These results could possibly help in the efforts to accomplish improvements in the composition of fatty acids in the milk.

Pattegrisdødelighed i Udendørs Sohold - Effekten af faringslængde i udendørs sohold på so positurskift og diegivningsadfærd i relation til pattegrisdødelighed

Thorsen, Cecilie Kobek, 30.06.2016

Abstract:
Hver tredje pattegris dør før fravænning i udendørs produktion, og dermed har den tidlige pattegrisdødelighed nået et uacceptabelt højt niveau både etisk og økonomisk. Der er et behov for viden med henblik på at reducere de negative konsekvenser af høj dødelighed på dyrevelfærd og produktivitet. Pattegrisdødeligheden er højest de første tre til syv dage efter faring. De primære årsager er dødfødsel, lagt ihjel af soen, hypotermi og sult. I den konventionelle produktion er disse årsager fundet relateret til stor kuldstørrelse og en lang faringslængde som følge af denne. Da søerne benyttet i udendørs produktion er af samme genetisk materiale af højtydende søer som benyttes i konventionel produktion forventes lange faringer også at forekomme udendørs. En lang faringslængde forventes at være udmattende for soen, forårsage smerte, ubehag og sygdom. Dette forventes at påvirke soens adfærd efter faring gennem svækket kropskontrol, når soen lægger sig, reduceret reaktion på at fange en pattegris under sig og muligvis også reduceret diegivningsmotivation. Disse er alle vigtige faktorer for pattegrisoverlevelse. Derfor var formålet med dette speciale at studere, hvordan faringslængde i et udendørs kommercielt sohold påvirker søernes positurskift og diegivningsadfærd de første tre dage efter faring.
Et observationsstudie blev udført på 31 søer fra fire faringshold. Faring og efterfølgende adfærd blev kontinuerligt filmet med videokameraer monteret inde i hver hytte. Derudover blev kliniske registreringer foretaget af symptomer for farefeber på hver so 24-72 timer efter fødsel af første gris. Resultaterne viste, at søernes adfærd efter faring ikke overvejende var associeret med faringslængde men i stedet med tiden siden fødsel af første gris. I de første 24 timer lå søerne længere i sideleje, var mindre udenfor hytten og udførte mindre præ-lægge-sig-adfærd i forhold til 24-72 timer efter faring. Pattegrisene masserede yver mere jo længere tid søerne brugte i sideleje. En øget massage øgede frekvensen af mælkenedlægning 48-72 timer efter faring. Kun to søer viste symptomer på farefeber.
Studiet viste, at udendørs søer kan have en lang faring uden, at dette påvirkede deres adfærd efter faring eller resulterede i farefeber. Dette kan skyldes forholdene i udendørs sohold med hensyn til indretning, redebygningsmateriale, fiberholdigt foder og mere adfærdsmæssigt frihed, der har en positiv effekt på søernes evne til at håndtere en lang faring.

The role of the phototransduction pathway for thermal adaption

Villadsen, Kathrine, 29.06.2016

Abstract:
The phenotypes of ectothermic organisms are shaped by the interaction between genetics and factors in the environment. Temperature is one of the most important abiotic factors, also influencing the distribution of such organisms. Ectothermic animals like the fruit fly, Drosophila melanogaster, is in particular sensitive to changes in the ambient temperature due to its small size. It has previously been shown, that heat shock proteins play a major role in protection against noxious the damage induced by stressful temperatures. However, other mechanisms are clearly involved as well and recent studies name the phototransduction pathway as a candidate for contributing to the thermal adaptation response. This pathway is otherwise known from our eyes, where it converts light into electrical signals for interpretation by the brain. This study investigates the potential role of the candidate genes from the phototransduction pathway for thermal adaptation. Through a gene knockdown system using mutant lines, the effect of knockdown of different genes were investigated for both behavioral and short-term acclimation responses to high temperature as well as for basal heat tolerance of flies. The experimental work revealed that the genes from the phototransduction pathway has very diverse effects on heat tolerance and heat response. Genes previously shown to be tightly connected in the phototransduction pathway had, when knocked down, surprisingly very different responses in both behavior and in induced physiological and evolutionary adaptation. This study elaborates on the current knowledge on phototransduction genes and discuss their significance for thermal adaptation.

Sexual selection and polyandry in the spider Pisaura mirabilis (Araneae: Pisauridae) – estimating natural mating rates and population structures

Lauridsen, Astrid, 29.06.2016

Abstract:
Polyandry is widespread and observed in many species and taxa. The costs and benefits affecting the evolution and maintenance of polyandrous mating are manifold and complex. Pisaura mirabilis is a nuptial gift giving spider found across Europe and both male and female mate multiply under laboratory conditions. Nuptial gifts contain nutrients and are therefore of direct material value to females. However, males can utilize two different nuptial gift giving strategies when courting females; either a genuine or a deceiving strategy. Males have been hypothesised to regulate nuptial gift giving strategy according to female re-mating rate and risk of sperm competition. Population differences in male nuptial gift giving behaviour have been observed and ecological conditions or genetic differentiation has been hypothesised to underlie these behavioural differences. As a first step to study the level of polyandrous behaviour of P. mirabilis under natural conditions, genotyping of offspring from wild caught females using microsatellite markers in combination with multiplex polymerase chain reaction (PCR) was performed. Polyandrous behaviour was studied in populations originating from three different collection sites in Europe; Denmark, Germany and Slovakia. Furthermore, the population genetic structure of two additional populations originating from collection sites in England and Italy were explored. The study found that broods are sired by up to four different males, showing that P. mirabilis females mate polyandrous in nature. Populations were genetically differentiated, indicating dispersal barriers between populations. This study gives the first estimates of polyandrous behaviour and population structure of P. mirabilis under natural conditions.

Arundo donax as a Paludicrop: Photosynthetic and Growth Responses to Nitrogen

Truelsen, Michelle Romberg, 28.06.2016

Abstract:
Elevated nutrient levels can have negative effects on aquatic biota and it is necessary to reduce nutrient loadings to the aquatic ecosystems. Wetlands often function as sinks for especially nitrogen. This is due to anaerobic soils, where denitrifikation can take place, where nitrogen is permenantly removed from the system. Nutrients can also be removed from the system if taken up by plants, if the plants are harvested. Paludiculture, the use of formerly drained land for wet agriculture use, is a way to use wetlands for nutrient removal to grow biomass to use as biofuels and other purposes. Arundo donax, a flood-tolerant grass with a high growth rate, has been suggested as a paludicrop, but information on how A. donax responds to nutrient availability is limited. The aim of this project was to determine the photosynthesis-N relationship in A. donax and to explore if N affected growth and leaf properties.  Plants were grown in five different N treatments (0.2 mM, 0.5 mM, 1 mM, 1.75 mM and 2.5 mM NH4NO3), and their biomass yield, growth (RGR) and gas exchange was determined. Results showed that photosynthesis was significantly positively correlated with leaf N content. It was also seen, that biomass (DW) was significantly higher in plants treated with 2.5 mM compared with plants treated with 0.2 mM NH4NO3.
Because of the species positive response to N availability and the high possible biomass production, it is reasonable to assume, that A. donax would function well as a paludicrop. The positive affect of N is however not as strong as seen with other paludicrops. This could indicate that A. donax is easier to grow in areas with low N compared to other paludicrops. Even though N only is available in limited quantities, A.donax can still maintain a high biomass production, yet less than if N was available in high concentrations.
Arundo donax is not found in the Danish nature, and since the species has shown invasive behaviour in several other countries, one must be careful to introduce A. donax for use in Danish paludicultures.

Immunogenetic Variation in the Endangered Cape Verde Warbler, Acrocephalus brevipennis

Mann, Hjallte Rosenstand, 24.06.2016

Abstract:
Functional genetic variation is the foundation for adaptation and its preservation is of high concern in the conservation of endangered species. Variation in immune genes such as toll-like receptors is of particular concern because of their direct influence on survival. This study reports on the extent and distribution of genetic variation in eight toll-like receptors for the three remaining populations of the endangered passerine species, the Cape Verde warbler (CVW), Acrocephalus brevipennis. Three loci showed clear signatures of selection, which suggests that they are or have been of functional significance. TLR3 and TLR4 had signatures of selective sweeps in the biggest population of Santiago, but not in the two smaller populations of Fogo and São Nicolau. TLR4 additionally showed patterns of purifying selection in the two smaller populations. A third locus, TLR2B, showed clear indications of balancing selection across all three populations. The distribution of variation in TLR1LA, TLR1LB, TLR2A, TLR5 and TLR21 followed the same pattern as neutral markers, with particularly low variation in the small population of São Nicolau. The evidence of selection demonstrates that genetic variation within the TLR system may be of particular importance for the adaptive potential of each of the three CVW populations. The population of São Nicolau may be especially vulnerable to any environmental changes because of its limited genetic variation. Care should be taken to maintain variation within these key genes in future management strategies for the species.

Anvendelse af laserscanning af vegetation (LiDAR) til at detektere faktorer, der styrer svampeartsrigdom og –artssammensætning.

Thers, Henrik, 24.06.2016

Abstract:
For at reducere den pågående og bekymrende tilbagegang i biodiversitet i Danmark og globalt er det nødvendigt at effektivisere brugen af de begrænsede midler til naturbeskyttelse og monitering af arter. Det kan blandt andet gøres ved brug af 'remote sensing', der er en fællesbetegnelse for teknikker, der kan indsamle informationer på kort tid over store afstande. En af disse teknikker hedder LiDAR (Light Detection And Ranging), som virker ved at scanne vegetationen med laserlys og oprette en samling af punkter med tredimensionelle koordinater som output. Denne form for punktskyer indeholder information om vegetationen, som kan bruges til at karakterisere de pågældende plantesamfund, og derudover til at sige noget om artsrigdommen og sammensætningen for andre grupper af arter, såsom fugle og insekter. I dette speciale bruges LiDAR-data til at modellere svampeforekomster. Data for svampe er stillet til rådighed af det omfattende danske biodiversitetsprojekt Biowide.

Specialet er inddelt i tre faser. Først georefereres 121 Biowide prøveflader (40 x 40 meter) ved GPS-opmåling af hjørner markeret med pæle samt en efterfølgende rekonstruktion af manglende hjørnemarkeringer for at opnå et komplet sæt af koordinater for alle prøveflader. Dernæst beregnes en række variable afledt af LiDAR punktskyen til at beskrive prøvefladerne. Endelig opstilles modeller til at beskrive svampe artsrigdom (total og rødlistet) og artssammensætning i prøvefladerne, udtrykt ved 3 NMS (Nonmetric Multidimensional Scaling) ordinationsakser. Der opstilles tilsvarende modeller med to andre sæt af forklarende variable i form af henholdsvis botaniske data (plante diversitet og Ellenberg-værdier), samt analyser af jord (fx pH, kvælstof og fugt) og løv (fx kvælstof og fosfor), lysmålinger og opgørelser af bestanden af træer i prøvefladerne. Til sidst kombineres de tre sæt af forklarende variable for at analysere unik og overlappende forklaringskraft. LiDAR-afledte variable har generelt større forklaringskraft eller indeholder supplerende information i forhold til andre typer af variable. Især den generelle artsrigdom og første aksen, som er en kombineret gradient for habitattype og succession, detekteres vellykket af LiDAR. Tredje aksen, som primært er en fugtgradient, detekteres lige godt af alle inkluderede typer af variable. Anden aksen, som er en jordbundgradient domineret af pH, samt antal rødlistede arter, detekteres dårligt af LiDAR.

Habitat modelling of bank voles using airborne lidar

Nielsen, Marie-Louise, Grønne, 24.06.2016

Abstract:
LiDAR is an active remote sensing technique that allows retrieval of 3-dimentional structures on the Earth's surface. LiDAR has been successful in estimation of different vegetative structures widely used to assess biodiversity and animal-habitat relationships. So far, LiDAR has mainly been used in studies of birds or large mammals and this study investigated whether the method also applies to a small mammal species i.e. a mice or vole. The Bank Vole (Myodes glareolus) is chosen as the model organism and a Resource Selection Probability Function (RSPF) was build to investigate habitat selection of bank voles in Mols Bjerge National Park. 16 transects were placed in different habitats and bank voles were captured with Ugglan live-traps each spring between 2010-2015. 209 bank voles were captured and the presence or absence of bank voles was used in model building. A generalized linear mixed model (GLMM) was used to relate binary data with different environmental variables. The environmental variables were estimated by LiDAR whenever the technique was feasible, or manually in the field. Two models were build to predict the potential distribution of bank voles: one only with LiDAR-derived explanatory variables and another with a mix of LiDAR and field-measured explanatory variables. The Corrected Akaike Information Criterion (AICc) was used for comparison among RSPF models and an area-under-the-curve (AUC) approach was used to investigate model performance. The LiDAR-derived model with maximum height of trees, cover of low-vegetation and a random intercept for transects performed good (AUC = 0.88) and was adequate in modelling habitat selection of bank voles in Mols Bjerge National Park.

Seasonal variation in structure, colour and shape of redial colonies of Himasthla elongata

Kristensen, Svend Uffe Tovborg, 22.06.2016

Abstract:
Recently, it has been suggested that redial colonies of some trematode species form two distinct morphological and functional castes within their gastropod first intermediate host: a soldier caste and a reproductive caste. The small “soldier” rediae readily attack invading competitors (other trematodes), while the reproductive rediae produce the next dispersal life stage, the free living cercariae. In Himasthla elongata infecting periwinkles (Littorina littorea) such social organization has been suggested based on the caste formation theory, however, this is debated since other studies have found germinal mass needed for reproduction in the small “soldier” rediae that therefore are not sterile. This indicates that the soldiers are just juvenile individuals which eventually develop into reproducing rediae. Redial size frequency distributions are commonly used as evidence for social organization, since they are usually bimodal and lack intermediately sized rediae, indicating presence of two distinct castes. However this could be explained by an age-dependent colony structure with arrested development in the juvenile rediae. In this study, it was found through thorough examination of redial colonies and their size frequency distributions that the rediae are bigger during summer, while the frequency of different size categories and hence also the total colony size is highest during winter. During winter the rediae tend to be degenerated and possess a brighter orange colouration compared to the summer period which suggests that the non-reproductive to reproductive redial ratio is affected by colony size and host shell height during winter, but not during summer whereas no difference was found in this ratio between seasons. These results indicate (1) that there is a renewal of rediae during winter when the old rediae are degenerating and (2) that the small rediae start production of cercariae during summer and hence grow by extension rather than proliferation. The study suggests that the colony structure is season- and age-dependent, and hence, the colony is inherently self-sustaining. However, it cannot be determined if the juvenile rediae have a specialized function before maturing that may justify the caste-formation hypothesis to be retained. Furthermore, the intermediately sized rediae are common contrary to other studies. The drop of these in summer could explain the missing intermediately sized rediae in other studies, simply due to local temperatures.

Effects of Fungicides on Aquatic Fungi and Trichoptera associated with leaf decomposition

Pristed, Mathias Skov, 22.06.2016

Abstract:
Streams are acknowledged as one of the most impacted ecosystems on earth. Be it through mechanical changes, nutrient enrichments or application of pesticides in close vicinity agricultural areas. However, a scarcely studied subject within the field of ecotoxicological impairments of stream ecosystems remains; effects of fungicides on non-target organisms. Fungicides are readily leached into the fresh water bodies of agricultural areas through a variety of entry routes. Here they may pose a threat to the freshwater environment by affecting both organisms and ecosystem functions. Of especial concern are the aquatic fungi known as aquatic hyphomycetes, a polyphyletic group of true fungi, that have crucial functions in relation to leaf palatability towards macroinvertebrates and leaf litter breakdown. The aquatic fungi are currently not included within the conducted ERAs and effects upon them may therefore be underestimated at risk of impairing ecosystem functions. Presently, the main contributors to assess toxicological effects of fungicides upon aquatic fungi are laboratory studies at unrealistically high exposure concentrations showing effects. They are however contradicted by field studies documenting effects at environmental concentrations. Furthermore, no long term studies exists to tests direct and indirect effects of fungicides upon leaf associated macroinvertebrates.

The present study sought to determine the effects of environmentally realistic fungicide exposures in a mesocosmic setup simulating stressors of the natural environments. Leaves (Fagus sylvatica), their associated aquatic fungi and trichoptera species (Anabolia nervosa and Chaetopteryx villosa) were jointly exposed within mesocosm streams to chronic low concentrations (two separate concentrations) of a fungicide mixture (prochloraz, prothioconazole, metalaxyl and pyrimethanil) in a time period of 5 months, until the emergence of the trichopterans. Chronic exposures were augmented by three days peak increasing concentrations by a factor 10 on a monthly basis (3 day duration), simulating peak exposures often noted during storm floods cooccuring with heavy rain fall episodes. Leaves were exchanged simultaneously with peak exposures, establishing fungi thus received the "worst case scenario". The design was optimized to detect chronic effects on fungal colonisation abilities, community structure and functions under various stresses, under the assumption that aquatic fungi, at certain stages of their life cycle are highly sensitive to fungicides and hence, indirectly influencing trichopterans. Measured endpoints were both structural (species richness, sporulation rate, community composition) and functional (biomass and decomposition), while trichopterans were assessed for feeding rate, emergence success and fatty acid- concentrations and composition. Furthermore, leaf palatability was tested for the applied concentrations through binomial feeding trials on leaves with Gammarus pulex. Palatability was tested to examine food choice behaviours of the macroinvertebrates.

Kristiansen, Anna, Kjærgaard, 22.06.2016

Abstract:
The growth of black cherry (Prunus serotina) in Denmark is not well documented. Black cherry is an alien invasive tree species in most of Europe. This study investigates five factors that can influence the growth of black cherry: floristic composition, pH-value, topsoil layers thickness, light composition, and soil-moisture. Growth of P. serotina was investigated at two sites located in Jutland in Denmark, Blåbjerg plantage near Holstebro and in Nordskoven near Silkeborg. At each site four transects with five plots in each transect were sampled, each plot was 2x2 meters and one transect was 2x10 meters. In each plot 10 samples of black cherry was collect to determine the age. Furthermore, in each plot the diameter of all individuals of black cherry was measured to estimate age of all individuals. This was estimated by a linear regression of diameter and age in the collect samples. To examine which factors significantly influence growth three models were made: one that covers all data from both sites, and one for each site. In the model that covers all data, it was found that the topsoil layers thickness and soil-moisture had a significant effect on growth of black cherry; the same was seen in the model with data from Blåbjerg plantage. In the model for data from Nordskoven was it pH-value and light composition that had a significant effect in the growth. Only the floristic composition was significant not in any of the models for the growth of black cherry. The growth of black cherry is complex and this study concludes that more research is needed in this field.

Integrating population viability analysis, genomics and spatial data using the European population of Little Owl Athene noctua as a model species

Andersen, Line Holm, 20.06.2016

Abstract:
Human induced landscape alterations are numerous, and affect both the abundance and distribution of many species. Especially the agricultural landscape has changed with resulting population declines in many species linked to this habitat. It is therefore important to determine the factor that the individual species depend on in order to understand their decline. As the landscape changes also result in habitat fragmentation, once continuous populations are turned into metapopulations. It is thus increasingly important to determine both the number of individuals it takes to create a genetically viable population and the population trend. Here, population viability analysis and habitat suitability modelling was used to determine the viability and future prospects of the Little Owl Athene noctua, a widespread species often associated with the agricultural landscape. The results showed a high risk of population decline over the coming 100 years. Populations towards the north of Europe are especially vulnerable, whereas populations towards the South-eastern part of Europe have a greater chance of remaining extant. In order to be considered genetically viable, individual populations must count 1,000-30,000 individuals. The Little Owl populations of several countries count less than 30,000, and cannot be managed as demographically independent without risking the loss of 5% genetic diversity or more over a 100 year period. The Little Owl might have to be managed across political borders. At a large scale and over a large range, the Little Owl is affected positively by increasing temperatures and urban areas, whereas an increased tree cover, an increasing annual rainfall, grassland and sparsely vegetated areas affect the presence of the owl negatively.

The Culturable Bacterial Community from Snow and Air Samples from Northeastern Greenland, and their Cold-Adaption Strategies

Pilgaard, Stephanie, 17.06.2016, speciale 

En geografisk analyse af potentielle levesteder for bæver (Castor fiber L.) i Danmark

Thøgersen, Sanne Egebjerg, 16.06.2016

Abstract:
The beaver (Castor fiber) is an originally native species in Denmark. Archeological finds have
shown that it thrived here, up until around 1000 – 2500 years ago, were it was most likely driven to
extinction by hunting and the destruction of its habitats.
Today the beaver has come back into focus, because it is a key species in creating some of the
dynamic and biodiverse habitats, which we wish to remake in Denmark.
The first 18 beavers were released into Klosterheden Plantage, the year after the decision to
reintroduce the species was made, and a count of the species, in 2013, show more than 203 beavers
living in the area. However, if the goal is for the species to be reestablished in the entire country
within the next decades, additional efforts must be made.
In this study, I have focused on which areas in Denmark could be used as additional release sites, by
creating an expert-based habitat suitability model, including the most important limiting factors,
namely suitable freshwater habitat, access to woody vegetation, and distance to unwanted human
disturbances. As well as comparing the resulting optimal habitats, with areas under governmental
protection, to accommodate private and industrial interests and thereby avoid unnecessary friction.
I extracted values, from my final habitat suitability model, to both random points in an area with
beavers and to know beaver locations and ran a Welch t-test, to see if the two groups differed from
each other. I found a significant difference between the areas, where beavers chose to settle and the
areas they chose to avoid.
My analysis shows that a very large percentage of Denmark presents as very suitable habitat, for
beavers. I also found that most of the protected areas in Denmark line up with the suitable areas
found with my model.
When comparing the locations of estimated suitable habitats and protected areas, two large areas of
high congruence in particular stood out. One by the west coast in southern Jutland and the other
around Lille Vildmose, in the eastern part of Central Jutland.
Both of these regions include areas are under national protection. They are both large enough to
sustain a population of beavers, both far enough away from private residences and industry to lessen
damages from beavers and both areas would benefit from the presence of beavers, because of their
ecological effects on enhancing mosaic habitats, increasing biodiversity and potentially reduce the
demand on habitat management. If the goal is for the beaver to be reintroduced into all of Denmark,
both of these areas could be used as additional release sites, to facilitate dispersal.

Keywords: Beaver, Habitat suitability model, biodiversity, optimal habitats, human interests.

Spatiotemporal Variations in Plant Communities at a Reclaimed Brown Coal Mining Area

Henriksen, Maria, 16.06.2016

Abstract:
Surface mining is one of the devastating activities of the Anthropocene, and by which landscapes and natural communities are altered beyond recognition. Knowledge of long-term effects of reclamation of such landscapes is still scarce. This study aims to identify the successional trajectories of the plant communities in the reclaimed brown coal mine in Søby, Denmark, and elucidate the environmental drivers that shape them.

In Søby, 35 locations were surveyed in 1984 and resurveyed in 2015. Overall differences in mean indicator values for the Søby area between the two years were tested with paired t-tests for Ellenberg indicator values, grassland utilization indicator values and Grime’s resource strategies. This revealed significant increases in Moisture, Productivity and Soil Reaction as well as decreases in Light and Foraging value for Deer.

Coarse-grained spatiotemporal ordination analyses were used to identify differences between locations from 1984 and 2015. A light-moisture gradient seperated the years with lower light and higher moisture in 2015. This reveals the process of succession over the past 30 years. Mined sites were increasingly resembling the reference sites of 1984 over time, which leads to the presumption of a successional trajectory towards pre-mining conditions. However, also reference sites have developed in new directions during the 30 year period, suggesting that most communities in Søby are continuously in a successional process.

In a fine-grained spatial analysis of the 2015 data, a significant gradient of deer activity was discovered. This indicates an interaction between plants and animals that might play a part in shaping of community composition and developement.

Overall, the findings of this study suggest a successional trajectory of reclaimed mining sites towards pre-mining communities. However, continuous changes in environmental conditions such as light, water availability and deer activity may prevent communities from reaching a stable state, even in the un-mined reference areas in the surrounding landscape.

Pløjning, historik og andre faktorers indflydelse på sandmarkers plantesamfund i Mols Bjerge

Sømod, Tobias Mosgaard, 10.05.2016, speciale

The Use of Wood Ant for Pest Control in Plantations

Nielsen, Jesper Stern, 31.05.2016, speciale

VMP II Vådområder - en evaluering af effekten på vegetationen

Hangstrup, Susan, 26.04.2016, speciale

Photosynthetic acclimation to light gradients in Typha latifolia

Jespersen, Emil Arboe, 31.03.2016, speciale

Adaption of two Methylobacterium strains isolated from rainwater to simulated stress factors in the atmosphere

Dreyer, Morten, 18.03.2016, speciale

Seasonal variation in the cell wall and storage polysaccharides content in large brown algae Saccharina latissima, Laminaria digitata and Fucus vesiculosus – effects of environmental factors

Janicek, Tina, 26.02.2016

Abstract:
Brown algae are a rich source of fucoidan, which is a carbohydrate located in the brown algae cell wall. Fucoidan possesses potential anticancer, antioxidant, anticoagulant agents resulting in having great potential as active ingredients for humans. Seaweeds are faced with different environmental changes throughout the year, resulting changes in the biochemical composition. However, the literature is almost non-existing of what causes the fucoidan to fluctuate. In this study, we investigated the impact of environmental factors as; salinity, availability of irradiance and nutrients, current exposure (REI) and temperature on the monthly content of fucoidan in Fucus vesiculosus (Grenaa and Fornaes), Laminaria digitata (Aarhus and Hanstholm) and Saccharina latissima (Aarhus). For supporting these observations appurtenant experiments was conducted. Our findings indicate 1) the highest concentration of fucoidan was found in F. vesiculosus (15%) compared to L. digitata (12%) and S.latissima (7% DM), with maximal concentrations in April, March and August respectively 2) fucoidan in all three species was influenced positively by irradiance and salinity, and negatively affected by the internal nitrogen content. These findings can provide information on when to harvest the algae. Further investigations are needed in order to fully understand the mechanisms behind the synthesis of fucoidan and to perform monthly surveillances for a longer period, to see if the yield is the same every year, to comply with the demand of fucoidan of the medical industry.

Characterization of health - associated Propionibacterium acnes strains

Jensen, Michael Grønskov, 26.02.2016, speciale

Factors Causing Distortion in Size-Frequency Distribution of Common Periwinkles (Littorina littorea) Infected by the Trematode Cryptocotyle lingua

Dall Hjøllund, Ellen, 24.02.2016

Abstract:
The parasitic flatworm Cryptocotyle lingua (Trematoda: Heterophyidea) has previously been observed to accumulate particularly in the largest/oldest individuals of the host populations of common periwinkles, Littorina littorea. Prevalence of other trematode species, such as Renicola roscovita and Himasthla elongata on the other hand decline after reaching a maximum in small to intermediate sized hosts and the causes are unknown. This study will try to reproduce the pattern in a Danish periwinkle population and investigate potential explanations.

The size-frequency distribution of C. lingua infected snails according to shell height was found to be significantly different from the distributions seen for uninfected individuals and snails harbouring other infections (R. roscovita and H. elongata).

Periwinkles infected by C. lingua had significantly large shells compared to uninfected individuals of the same age, a seemingly manipulated growth rate and smaller condition factors, indicating a gigantic growth (at least in terms of shell-growth) of this long-lived snail host caused by C. lingua infection. Gigantism might therefore be a possible explanation for the distribution pattern.

Two separate rediae morphs (small and large) were found within C. lingua colonies, and observed to attack sporocysts of R. roscovita both in vitro and in vivo. The small rediae attacked R. roscovita at a significantly higher rate than large rediae, cautiously suggesting a division of labour between the two. However, small rediae showed little interest in attacking rediae of H. elongata (in vitro) even though they, in theory, poses the biggest threat to the C. lingua colony because of their antagonistic potential. Yet, C. lingua rediae are assumed to evade invasions of other trematode competitors, also H. elongata, and eliminate sporocyst colonies from hosts already infected. In this way antagonistic behaviour may contribute to C. lingua’s dominance in the largest snail hosts. Besides seemingly functioning as defence, small C. lingua rediae appear to play an additional “cleaning” role in the colony by removing dead or dying cercaria and rediae.

Several factors may explain the distortion in host size-frequency distribution of infected periwinkles in addition to gigantism and antagonism investigated in this study. Varying virulence levels (with C. lingua being the least virulent), different trematode abundances in the environment, and species-specific host size preferences are discussed. A significant relationship was found between foot colour and C. lingua infection, with infected snails being dark orange and uninfected light yellow/grey. The orange colour has been proposed to be caused by a parasitic destruction of the digestive gland, which could indicate some level of pathogenicity of C. lingua, speaking against the hypothesis of varying virulence.

Host shell growth response to different trematode infections (gigantism, stunt or normal growth) is considered the most likely explanation for the distribution pattern, but any exhaustive explanation is probably multifaceted.

Sex-biased dispersal and plate-biased dispersal in sticklebacks (Gasterosteus aculeatus)

Bertelsen, Mia Smedegaard, 19.02.2016

Abstract:
Sex-biased dispersal er et resultat af parringssystemer. Mange arter, der lever i polygyni, viser male-biased dispersal, hvorimod monogame fugle viser tegn på female-biased dispersal. Den trepiggede hundestejle lever i et polygamt parringssystem, hvor hannerne konkurrerer omkring territorier og at finde sig en partner/mage. Derfor vil man ud fra parringssystemet tro, at den trepiggede hundestejles hanner har en tendens til at migrere længere end hunnerne (male-biased dispersal). For at undersøge sex-biased dispersal i trepiggede hundestejlere har jeg anvendt SNPs fra ferskvands- og marine populationer af trepiggede hundestejlere. Herefter blev FST, mAIc (mean Assignment Index) udregnet og en spatial
autocorrelations analyse vha. GENALEX version 6.5 blev udført. Resultaterne viste dog ingen signifikans for hverken FST og mAIc. Den spatiale autocorrelations analyse viste heller ingen signifikans ved hanner og hunner for sex-biased dispersal. Udover sex-biased dispersal blev også plate-biased dispersal testet. Den trepigggede hundestejle kan have forskellig morfologi, alt efter om den lever i ferskvand eller
saltvand. De fleste hundestejler fra saltvandspopulationer er full-plated, mens hundestejler fra ferskvand har få laterale plader på kroppen og kaldes for partial/lowplated. De forskellige morfologier kan skyldes de forskellige habitater, som hundestejler lever i. Saltvandspopulationer skal beskytte sig mod predatorer, mens hos ferskvandspopulationer kan abiotiske faktorer være skyld i reduceret antal plader, men der kan også være tale om selektionstryk fra insekter, der angriber hundestejlen, og hvor få plader er en fordel. Da marine hundestejler migrerer mere, ville det forventes at se full-plated biased dispersal. For at teste for plate-biased dispersal blev samme analysemetode af SNPs brugt, som ved sex-biased dispersal. Den spatiale autocorrelations analyse viste at full-plated individer migrerede over en længere afstand end partial/low-plated individer, fra de bliver født og til de reproducere sig, nemlig 789,8 meter i forhold til 730,8 meter. Resultaterne viser derfor ingen tegn på sex-biased dispersal, men der er dog nogle indikationer på full-plated dispersal.


Mating system, sexual behaviour and degree of polyandry in a population of the sedentary spider, Agelena labyrinthica (Agelenidae)

Kreilgaard, Nikolai Tvilling, 10.02.2016

Abstract:
Males and females may differ in optimal mating rate, where females generally are limited by available resources, while males are limited by their access to females. This causes males to be under selection to mate multiply, while this is not always optimal for females. Males may compete with other males for females, but intrasexual adaptations may cause females to experience detrimental fitness. This may cause females to evolve resistance, and forces males to try to overcome these defences, with the potential of creating an antagonistic coevolutionary arms race. In this study, the mating system and sexual behaviour of the spider A. labyrinthica (Agelenidae) was investigated. A field survey was conducted to quantify the operational sex ratio and female encounter rate with males in a natural setting, showing an initially high ratio of males which sharply decreased over the mating season and remained low. Females were observed to generally mate with a single male only in the field. Semi-controlled mating trials were conducted to determine female remating propensity and sexual behaviour. This showed that females became less prone to mating when no longer virgin, showing higher degree of cannibalism. Males induced catalepsis in females, which helped in mating with females. Courtship duration decreased significantly in subsequent matings, while copulation duration did not differ significantly. Benefits or costs to female fecundity associated with mating a single or several different males was investigated by measuring egg production, but no effect was found. Data from the field study and mating trials suggested the mating system of this population to be monandrous or bigamous. This was based on the consistency between a low male encounter rate observed in the field, and resistance of females to remate after losing their virginity seen in the mating trials. Females became more aggressive, cannibalising males more often than when they were virgins, while they gained no benefits in fecundity from consuming males. The presence of sexual behaviour that seem to manipulate females (catalepsis), together with heightened non-virgin female aggression may suggest the presence of a sexual conflict. This conflict revolves around males attempting to mate with females beyond their optimal mating rate, resulting in female resistance that males need to overcome.

Vegetation Changes on the Savannah of Mara North, Kenya, during 1995-2015

Pilgaard, Jeppe, 09.02.2016

Abstract:
On Landsat imagery, the vegetation changes in Mara North during 1995-2015 were assessed in this study. Influences from different factors (stream distance, altitude, settlement distance, depressions and soil types) on the vegetation types in different years were tested. This study suggests an increase of woodland in Mara North, Kenya, and a transition from dry grass plains to grass plains consisting of a mosaic of grass and scattered woody vegetation. The study shows that especially the mountain areas have experienced great changes in vegetation, where former areas consisting of scattered woody vegetation now are dominated by dense woodland, and scattered woody vegetation has relocated to lower altitudes close to water. A negative correlation was found between rocky plains and distance to settlements, suggesting a high grazing pressure close to settlements resulting in dry savannah areas. Knowledge provided from this study regarding vegetation changes can be used for evidencebased management in Mara North e.g. where to located grazing zones and where not to.

The effect of long-term changes in host resource availability on colony structure and colony fitness of the trematode species Himasthla elongata and Renicola roscovita infecting the common periwinkle (Littorina littorea)

Juhl Halvorsen, Frej, 28.01.2016

Abstract:
Life cycles of the trematode species Himasthla elongata and Renicola roscovita are complex involving three different hosts, and for both species the long-lived common periwinkle (Littorina littorea) serves as the first intermediate host, wherein they exist as a clonal colony. The life-history of these trematodes differs in that the parthenogenetic generation of R. roscovita consists solely of immobile sporocysts, while in H. elongata it consists of mobile larval rediae. It was recently suggested that these rediae are divided into physically and functionally distinct castes, giving a caste of small non-reproducing soldiers specialized for defense against hetero- and conspecific competitors, and a caste of larger reproductive rediae producing both progeny rediae and the free-living dispersal stage; cercariae. Both trematodes have been reported to alter consumption rates and growth in their hosts, and both are frequently observed parasitizing Danish populations of L. littorea. Host growth and condition, as well as trematode colony structure and fitness, was examined in snails experimentally subjected to ad libitum food or moderate starvation for five months in laboratory mesocosms. Infection prevalence and mortality were found to be equal among well-fed hosts and hosts subjected to moderate starvation. Both trematode species were able to adjust the exploitation of their hosts as both species are found not to induce higher mortality in stressed hosts and, furthermore, not to occupy more or less of host abdominal tissue when hosts are stressed, though colonies of R. roscovita takes up significantly more space of host abdominal volume than H. elongata. Both infection and reduced resource availability significantly lowered host condition, yet host shell growth, and in turn, shell height were only affected by host resource availability. The ratio of non-reproductive to reproductive rediae in H. elongata colonies increased approximately 45% when hosts were moderately starved, and the maximum volume of reproductive rediae increased approximately 40% when hosts were well-fed. The treatment-effect on redial type ratio was found to be caused by the better overall condition of well-fed host snails. Cercarial output was found for both species to be lower in colonies in hosts subjected to moderate starvation. The lowered cercarial output of H. elongata colonies was caused by lowered host condition, while the lowered cercarial output of R. roscovita was caused by the size of the trematode colony.

Keywords: Caste structure, cercariae, colony fitness, Himasthla elongata, host condition, host growth, Littorina littorea, parasitism, rediae, Renicola roscovita, resource availability, trematode, virulence

Effekten af frøtilsætning på riparisk vådområde: Status 7 år efter

Amstrup, Lars, Jørgen, 28.01.2016

Abstract:
From 1900 Denmark had a wetland area around 670.000 ha and today that number is around 230.000 ha. The decline comes from agricultural development, hydrological changes and shifts in grazing and mowing. Combined and over a hundred years later the biodiversity is threatened. Laws have been made to protect the remaining areas, which have retained its biodiversity. Furthermore, wetland restoration projects have been launched. However, restoration projects have faced a problem with establishing the flora, because of limited seed sources from which seed migrations can originate.
In 2009 an investigation was launched to examine whether seed germination and establishment of five species in three different plant-quality areas in a meadow could be used to enhance the plant diversity. The purpose of this thesis is to reexamine the same five species seven years later to see if they are able to form a permanent presence in the three different plant-quality areas. In 2015 an investigation in to the effect of light intensity at ground level and vegetation height on the five species length of growth in conjunction of the areas plant-quality. 
In a Danish wetland area five test plots and five control plots were randomly placed in each of three areas, which were divided by the plant quality. One area of good plant quality, one of intermediate and one of poor quality, defined by the presence of fen indicator species. After a flooding period in the test plots, a mixture of seeds was added along with sediment. The seed mixture was composed of: Comarum palustris, Lychnis flos-cuculi, Lotus pedunculatus, Carex panicea, and Briza media, which are all indicator species of high-quality wetlands. The next seven years a continuous examination of their establishment and abundance were made. In 2015 the last year of the investigation, measurements of the vegetations height, light intensity and length of growth were also conducted. It was found that L. flos-cuculi and L. pedunculatus established a lasting abundance in all the three areas. The other three species did not succeed in establishing a lasting presence.  Differences in establishment success of the added seed-species can be explained by their adaptations to biotic and abiotic conditions reflected in their life-strategy and nutrient tolerances. The two species established themselves in the poor area because of the help from the flooding and sedimentation prior to the seed addition.
Vegetation height and light intensity displayed no difference compared to the three areas. It was only possible to measure the growth length for L. pedunculatus and the measurements showed that L. pedunculatus grew faster in the test plots than the control plots. This was credited to the tougher competition for light in the test plots.
This study has shown that seed addition can be used as a means to increase plant diversity in wetlands of low quality for L. pedunculatus and high and low quality for L. flos-cuculi. Therefore, seed addition can be recommended in combination with flooding and sediment deposition followed by maintenance operations of the meadow.

Vækst og fotosyntese hos Typha latifolia som funktion af fosfor- og kvælstoftilgænglighed

Hollensen, Pernille, 22.01.2016

Abstract:
Paludiculture er en dyrkningsform, der anvendes i vådområder. De overjordiske dele af vegetationen høstes og anvendes, som eksempelvis biobrændsel, mens resten efterlades til tørvedannelse. Anvendelsen af paludiculture kræver viden og forskning i planters næringsrespons, i hvordan udledningen af metan og næringsstoffer minimeres samt hvordan udbyttet af biomasse maksimeres. Relationen mellem kvælstof (N) og den lysmættede fotosynteserate (Amax) er velkendt, mens sammenhængen mellem fosfor (P) og Amax er mindre kendt. Formålet med dette projekt er derfor at undersøge hvordan tilgængeligheden af P påvirker effekten af N på vækst og fotosyntese hos Typha latifolia (bredbladet dunhammer). Vi ønsker desuden at undersøge hvordan P påvirker relationen mellem N og Amax. Planter af T. latifolia blev dyrket i 27-29 dage i et vækstkammer. Eksperimentet var opstillet som et 3x3 faktorielt design med faktorerne KH2PO4 (0,1, 1,0 og 10,0 mg PO43- L-1) og NH4NO3 (1, 20 og 70 mg NH4NO3 L-1). Planternes maksimale lysmættede fotosynteserate, tørvægten, og koncentrationen af N og fotosyntetiserende pigmenter blev efterfølgende bestemt. Resultaterne viste, at bladenes maksimale fotosynteserate påvirkes signifikant af N og af en interaktion mellem N og P. For det arealbaserede udtryk så vi, at effekten af N øges med tilgængeligheden af P. Typha latifolia kan udnytte selv høje koncentrationer af N og P til øget vækst og fotosyntese og vil derfor med fordel kunne anvendes til paludiculture, hvis næringstilgængelighederne er høje.

Vegetationsdynamik på Lyngby klithede analyseret på basis af historiske luftfotos 1954-2014

Jensen, Louise Aaen, 13.01.2016,

Abstract:
Anthropogenic activities have led to a decline of dune heathlands in northwestern Europe, which threatens the existence of this unique ecosystem and its species.  Here we focus on an approx. one square kilometer of coastal foreland  in NW Denmark, which is mainly occupied by dune heath. Trends in the vegetation dynamics during the past sixty years (1954-2014) were studied using historical aerial photos.  Vegetation patches identified by visual inspection of the photo were verified by performing vegetation analysis on ground. This resulted in the identification of four overall vegetation types: open sand, grey dune, dry heath and wet heath. Historical aerial photos from 1954, 1975, 1981, 1995 and 2002 were digitized and analyzed for trends in vegetation dynamics. The analyses revealed a cyclical pattern in vegetation development over time with a turnover rate of 6 percent per year.  The vegetation in approx.. 28 percent of the study area did not change during the 61 years for which information was available. Coastal erosion resulted in recession of the coastline of approx. 100 meters concurrent with a decline in sand area of approx. 41 % suggesting that coastal squeezing is currently taking place. The total area of grey dune increased by approx. 12 percent indicating efficient anthropogenic stabilization of sandy soils from wind erosion. The total area of wet heath increased approx. 37 percent, most likely as a result of the cancellation of trenches in the upland area.  The corresponding loss of dry heath was approx. 29 percent.

 

 

Afrikanske honningbier (Apis mellifera scutellata) og deres forbindelse til Varroa destructor bårne virusser: Deform Vinge Virus og Varroa Destructor Virus

Lemming, Katrine, 11.01.2016

Abstract:
Honningbier (Apis mellifera sp.) spiller en vigtig rolle i vores økosystem. De bestøver op til en tredjedel af de globale fødevareafgrøder, både direkte (f.eks. af hvede, frugt og grøntsager) eller indirekte (f.eks. af foder til vores husdyr). Flere og flere kolonier af honningbier dør, og man er bange for de konsekvenser, der kan følge heraf. Det er vigtigt at finde ud af, hvordan dette problem skal administreres for fortsat at kunne forsikre fødevaresikkerhed, økonomien og biodiversiteten i naturen. Kolonitab er steget især i USA og i mindre omfang i Europa. På verdensplan er det på vej til at blive et stort problem. I 2014 annoncerede en kenyansk biavler, at han også havde problemer med store tab af kolonier fordelt rundt i den sydvestlige del af Kenya. Han havde fundet varroamider (Varroa destructor) i sine bistader.
Varroamiden er en parasit af honningbier, der har været kendt siden 50'erne i Asien, 70'erne i Europa og 80'erne i USA. I 90'erne blev de opdaget i Sydafrika, og i nullerne blev miderne også fundet i Østafrika. De menes, at være en af hovedårsagerne til at kolonierne kollapser. Desuden bærer miden på en virus, som den overfører til honningbier. Virussen Deform Vinge Virus (Deform Wing Virus: DWV) forårsager deforme vinger og en høj dødelighed hos honningbier. Uden parasitisme af varroamiden kan honningbier stadig være inficeret med virus, men oftest på et ikke-dødbringende niveau. Når både mide og virusset forekommer i
kolonierne, bliver kombinationen dødelige.
Prøver fra den kenyanske biavler blev sendt til Danmark for at blive screenet for virus. Det var forventet at finde Varroa destructor Virus (VDV-1), som er en variant af og tæt relateret til DWV. VDV-1 har vist sig at være den hyppigste virus af de to i afrikanske lande. Prøverne blev testet for begge virus, og VDV-1 blev som forventet fundet.
Jeg besluttede at designe mine egne qPCR primere til at screene prøverne, da de eneste tilgængelige primere var end-point PCR-primere fra 2008. Over tid sker der mutationer, og det var ikke sikkert, at de gamle primere ville passe på en ny variant af virussen. Desuden udviklede jeg qPCR primere i stedet for end-point PCR primere, da de er mere følsomme over for forekomst af virus, og de giver mulighed for hurtigere analysering af flere prøver på én gang. Mine nye primere registrerede dog ikke flere virus end de tidligere end-point PCR-primere.
For at teste mine primeres spændevidde, screenede jeg danske bier med tydelige symptomer på DWV. Bierne blev screenet med både DWV primere og mine VDV-1 primere. Begge primere testede positive, hvilket kan indikere det første fund af VDV-1 i Danmark. Yderligere sekvensering er nødvendig for endeligt at kunne konkludere dette.

Vertical distribution of zooplankton with emphasis on variation in lipid content and stable isotope signatures in Calanus finmarchicus in the deep part of Skagerrak

Pedersen, Christoffer Bruus, 10.12.2015, speciale

Udvikling af feltmetode til demografiske studier af hedepletvinge Euphydryas aurinia

Lauridsen, Nanna Renee, 04.12.2015, speciale

Analyzing the community based wildlife management approach in preventing the loss of biodeversity in Africa

Lippert, Carina Sparre, 07.09.2015 speciale

Udviklingen af den vilde flora på braklagte arealer

Ring, Susanne, 03.07.2015, speciale (PDF)

Effekter af fint sediment og lambda - cyhalothrin på makroinvertebrater

Spangsmose Bak, Ida, 22.06.2015, speciale

Konkurrenceforhold og rumlig fordeling af skovbundsplanter i bøgeskov

Tagø, Emma Line, 17.06.2015, speciale

Stabil isotopanalyse af fødekæder i lavarktiske søer og vandløb herunder betydningen af fisk

Buchardt, Marie, 29.05.15, speciale

Patterns of hydridization in North Atlantic eel

Andersen, Line Smedegaard, 23.04.2015

Abstract:
Hybridisering mellem tæt beslægtede arter er med til at øge vores forståelse af hvordan mekanismerne bag artsdannelse fungerer. Tidligere studier har vist at den europæiske, Anguilla anguilla, og den amerikanske ål A. rostrata, der begge gyder i Sargasso Havet, er i stand til at hybridisere, hvor størstedelen af hybriderne ender i Island. Dette studie vil analysere nye og gamle genetiske SNP data fra ål indsamlet i Sargasso havet, Island, Færøerne og Marokko for at klarlægge om der findes I) spatial eller II) temporal variation i hybridisering og III) om der er bevis for selektion der agerer på de anvendte genetiske markører der kan påvirke klassificering af hybrider. Der blev fundet meget lidt hybridisering i Sargasso havet og intet bevis for at en specifik region skulle have høj hybridisering blev fundet. Uden for gydeområdet i Sargasso havet blev der kun fundet hybrider i Island. Da der blev fundet en andel af hybrider i Sargasso havet på 2,2 % i 2007 og 0,4 % i 2014, og der ikke blev fundet nogen F1 hybrider nogen af årene, kunne det tyde på at der er en temporal variation in hybridiseringen. Analyser af de specifikke genotyper af hybriderne viste at der var problemer med at klassificere hybriderne korrekt. Dette skyldes sandsynligvis direktionel selektion på de SNPs der blev brugt i analysen.

Patterns of hydridization in North Atlantic eel

Andersen, Line Smedegaard, 23.04.2015

Abstract:
Hybridisering mellem tæt beslægtede arter er med til at øge vores forståelse af hvordan mekanismerne bag artsdannelse fungerer. Tidligere studier har vist at den europæiske, Anguilla anguilla, og den amerikanske ål A. rostrata, der begge gyder i Sargasso Havet, er i stand til at hybridisere, hvor størstedelen af hybriderne ender i Island. Dette studie vil analysere nye og gamle genetiske SNP data fra ål indsamlet i Sargasso havet, Island, Færøerne og Marokko for at klarlægge om der findes I) spatial eller II) temporal variation i hybridisering og III) om der er bevis for selektion der agerer på de anvendte genetiske markører der kan påvirke klassificering af hybrider. Der blev fundet meget lidt hybridisering i Sargasso havet og intet bevis for at en specifik region skulle have høj hybridisering blev fundet. Uden for gydeområdet i Sargasso havet blev der kun fundet hybrider i Island. Da der blev fundet en andel af hybrider i Sargasso havet på 2,2 % i 2007 og 0,4 % i 2014, og der ikke blev fundet nogen F1 hybrider nogen af årene, kunne det tyde på at der er en temporal variation in hybridiseringen. Analyser af de specifikke genotyper af hybriderne viste at der var problemer med at klassificere hybriderne korrekt. Dette skyldes sandsynligvis direktionel selektion på de SNPs der blev brugt i analysen.

Historical changes in the Danish butterfly community and the effect of changing land cover

Skovgaard Brandtoft, Emil, 31.03.2015

Abstract:
Butterfly species richness has been declining all over Europe during the 20th century. This decline is mostly due to changes in land use with intensification of agriculture as the primary cause. Several studies have shown that butterfly species with different life history traits shows different population trends through time. The declining status of butterflies is also true in Denmark. We investigate whether different species assemblages in the Danish butterfly community show different trends by analyzing the changes during three 10-year periods compared to the most recent 10-year period (1970-1979vs2003-2012, 1980-1989vs2003-2012 and 1990-1999vs2003-2012) at three different spatial scales (10x10 km, 50x50 km and at national level). We test whether these trends can be explained by historical changes in land cover/use measured in 10-year periods from 1900-2010. We further investigate whether open land species respond to edge effects in the current distribution of protected nature types. The results show strong declines in all species assemblages during the second 10-year period. No clear relationship between species richness changes and historical land cover/use changes were found, but there is some indication of extinction debt in some of the species assemblages. The unclear results indicate that the butterflies not only responds to changes in habitat area and that other factors, like habitat quality and climate change, are to be considered as well.

Historical changes in the Danish butterfly community and the effect of changing land cover

Skovgaard Brandtoft, Emil, 31.03.2015

Abstract:
Butterfly species richness has been declining all over Europe during the 20th century. This decline is mostly due to changes in land use with intensification of agriculture as the primary cause. Several studies have shown that butterfly species with different life history traits shows different population trends through time. The declining status of butterflies is also true in Denmark. We investigate whether different species assemblages in the Danish butterfly community show different trends by analyzing the changes during three 10-year periods compared to the most recent 10-year period (1970-1979vs2003-2012, 1980-1989vs2003-2012 and 1990-1999vs2003-2012) at three different spatial scales (10x10 km, 50x50 km and at national level). We test whether these trends can be explained by historical changes in land cover/use measured in 10-year periods from 1900-2010. We further investigate whether open land species respond to edge effects in the current distribution of protected nature types. The results show strong declines in all species assemblages during the second 10-year period. No clear relationship between species richness changes and historical land cover/use changes were found, but there is some indication of extinction debt in some of the species assemblages. The unclear results indicate that the butterflies not only responds to changes in habitat area and that other factors, like habitat quality and climate change, are to be considered as well.

Undersøgelse af det epidemiologiske og genetiske overlap mellem fedme og alkohol indtag og afhængighed

Johansen, Malan, 13.03.2015

Abstract:
The common complex disorders of obesity and alcohol use disorder (AUD) are recognized as major health problems, due to their associations to a large number of co-morbidities and premature mortality. Complex disorders are characterized by complex inheritance patterns, where both genetic pre-disposition and environmental factors interact, making the identification of susceptibility genes particularly challenging. In recent years, an emerging view has been that obesity and alcohol addiction are consequences of ingestive behaviors gone awry, mainly through shared disruptive brain reward circuitries that mediate food and drug motivated behavior. Hence, the overall aim of this thesis was to investigate the epidemiological relationship between obesity and alcohol consumption and to possibly identify genetic variants conferring risk for both obesity and alcohol consumption/AUD. This thesis included three studies:
In the first study (study I), the relationship between obesity and alcohol consumption was investigated. A significant relationship was established between these two phenotypes. Alcohol intake was found to be inversely associated with BMI in women but not significantly in men, while alcohol intake increased central adiposity in both sexes. Light to moderate consumption seemingly protected against overall weight gain. Higher levels of consumption were however a risk factor for central fat deposition.
In the second study (study II.A), it was investigated if a genetic overlap could be established between obesity and alcohol consumption. Genome-wide significant variants associating with BMI and WHR were investigated for their cumulative association with alcohol consumption by use of two genetic risk scores, one representing overall obesity (BMI variants) and one representing central obesity (WHR/WC variants). Moreover, it was investigated if an interaction effect between risk scores and alcohol intake in relation to BMI and WHR could be detected. Neither the BMI nor WC/WHR risk scores were found to associate with risk of alcohol consumption in men or in women. Furthermore, no interaction effects were detected between a high genetic load of BMI or WHR/WC associated variants and alcohol consumption in relation to overall or central obesity.
The third study (study II.B), similarly to the second, addressed the potential genetic overlap between obesity (BMI, WHR and WC) and alcohol consumption. However, in this study the opposite approach was undertaken. Variants within a gene-network cumulatively associated with AUD were tested for association with obesity by single SNP analyses. Only one SNP rs2727603 within gene CTNND2 was found to be significantly associated with WHR after multiple testing corrections, which could be mediated through preferential fat deposition in the central abdominal area. However, the association could not be replicated in GIANT or in an internal cohort
likely making this a spurious association. The lack of significant associations may be ascribed to a too low statistical power to detect effects and larger homogenous sample sizes are thus warranted.
To summarize, this study contributed to the ongoing exploration and understanding of the possible overlaps between obesity and alcohol consumption/AUD. An epidemiological relationship was established, however, the hypothesis of shared genetic burdens was not corroborated.

Habitat selection by red deer (Cervus elaphus) at a former brown-coal mining area

Dahm, Maria, 18.12.2014

Abstract:
Knowledge about red deer habitat selection in anthropogenic landscapes, and their impact thereon, is essential in ecosystem management with the intention of preserving and supporting broader distribution of red deer. I studied red deer habitat selection at a former brown-coal mining area in Søby, Denmark. The research was carried out from April 2014 to July 2014. For 93 randomised sampling sites, quantification of dependent and independent variables was performed. Faecal pellet presence from red deer was used as an indicator of habitat use of the sampling site. The method was validated with the application of Spypoint BF-6 Invisible LEDs trail cameras to 30 sampling sites. A significant difference was found between the amount of red deer activity detected with camera in sampling sites, with vs. without faecal pellets (ANOVA, p = 0.004). Independent variables consisted of both natural ecological and anthropogenic parameters. Human disturbance was negative correlated with habitat selection by red deer (p = 0.003), while forage availability, tree cover and mean terrain height was positively correlated with habitat selection by red deer (p = 0.020, p = 0.026, and p = 0.004 respectively). I conclude that in hunted red deer populations, human disturbance, as well as forage availability and tree cover are important factors in red deer habitat selection and should be considered in habitat management, with the goal of attracting red deer to places, where nature can benefit from their grazing pressure.

Grødeskæring i Danmark - hydrologiske og planteøkologiske effekter i mellemstore og store vandløb

Simonsen, Just, 18.12.2014,

Abstract:
1. Weed-cutting is performed regularly in most larger Danish streams to ensure efficient drainage of water from agricultural land. However, weed-cutting is known to cause major disturbances on aquatic plant societies and alter physical conditions to the detriment of in-stream biota. The first objective of this study was to investigate weed-cutting frequency and timing, macrophyte regrowth speed following weed-cutting and the effect of weed-cutting on water levels in Danish lowland streams. The second objective was to identify relationships between results from the first objective and stream conditions including physical and chemical parameters, dominant plant traits and EQR (ecological quality ratio). 

2. The database HYMER was used to investigate hydrometric data from 126 Danish stream reaches over a period of 23 years. The results were correlated with information from the national environmental monitoring programme NOVANA and information on dominant plant traits acquired from a concurrent PhD-project (Cavalli et al. 2014).

3. My results clearly indicate that macrophyte species in frequently cut streams share traits associated with adaptations to life in disturbed habitats. I also found evidence that EQR goes down when cutting frequency goes up. The effect of weed-cutting on water level was greatest during summer in streams dominated by plants with traits associated with high hydraulic resistance. Few other studies have quantified drainage efficiency before and after weed-cutting and related results to specific stream conditions, but such knowledge can help to optimize stream management and reduce negative environmental impacts.

 

Investigation of activity and gene expression of Methylobacterium during growth on methanol as sole carbon and energy source

Andersen, Lasse Kramer, 15.12.2014, speciale

Evolution, cognition and religion: Religious ideas in evolutionary and cognitive perspective

Jørgensen, Mads Ingersgaard,10.12.2014

Abstract:
This master thesis investigates how a combination of insights from the cognitive science and evolutionary psychology can be used within cultural studies in order to explain some aspects of religious thought and behavior.

Through a description of how the brains evolved cognitive mechanisms extract and compute information from the enviroment – in other words: how the brain thinks, learns and creates meaning to its surroundings – the thesis argue how these mental mechanisms has an impact on how religious ideas arise and is shaped. It is highlighted how religious thought (such as ideas of gods and other supernatural agents) emerge from a web of basic cognitive mechanisms and capacities shaped by natural selection during the development of the human mind.

The thesis demonstrates that a combination between cognitive science and evolutionary studies offers a new understanding of why people think and behave the way they do, and thus why religious ideas is found everywhere in the world and which characteristics these ideas have in common. Thus it is suggested that there are some core religious elements concerning religious ideas that can be seen cross-culturally, and that these similarities stems from universal and basic features of the human mind.

The thesis argue that a cognitive and evolutionary approach offers some obvious opportunities for interdisciplinary collaborations between biology and cultural studies.

Pelagisk næringsstofoptag i et stort dansk vandløb

Holm, Lotte, 03.12.2014, speciale

Test af mulige synergetiske interaktioner mellem frysegrader og bly (Pb) kontaminering i grønlandske blåmuslinger (Mytilus edulis)

Juhl, Bodil Klein, 02.12.2014, speciale

Gene expression responses to heat stress in threespine sticklebacks from ecologically divergent environments

Dammark, Karin Brydsø, 21.11.2014,

Abstract:
Increasing temperatures due to climate change pose a threat to many organisms. Ectothermic animals like fishes are extremely dependent on temperature, as they are not able to change body temperature physiologically. When populations are found in isolated water bodies such as small lakes they will have to respond to stressful high temperatures either by acclimation or evolutionary adaptation. In this study we analyzed sticklebacks from two large and two small lakes, assumed to represent different environments with respect to temperature. We determined maximum critical temperature (CTmax) for threespine sticklebacks, and we further assessed if they show stress responses at the highest temperatures that they currently encounter in the wild. This was done using real-time quantitative polymerase chain reaction (qPCR), to assess the relative expression of three heat shock related genes (hsp60, hspa8, hsp90), and two genes involved in metabolism (idh2, fbp2) at different temperatures. Fish were exposed to three treatments; exposure to 26ºC at 24 hours and 48 hours, and exposed to increasing temperature until CTmax was reached. We found similar CTmax, across all populations i.e. 31.5ºC. Regulation of hsps and metabolic genes showed inverse relationships, confirming general notions of costs incurred by upregulating hsp expression. The results suggest that stress response is starting somewhere between 26ºC, where we observed slight signals of stress at the gene expression level, and 31ºC. We found no evidence for local adaptation at CTmax, and at the weakly stressful temperature of 26ºC the only significant gene expression differences observed possibly reflected non-adaptive effects, even though levels of genetic variation did not suggest stressed fish to be derived from an inbred population. We conclude that threespine sticklebacks do not show severe stress during the warmest temperatures they are likely to encounter during current temperature regimes, but future climate change could severely affect populations, especially in small, isolated water bodies. Our results add to a growing body of studies that show similarity of basic physiological properties like CTmax across populations, but do not rule out adaptive responses at other traits of importance to accommodate the challenges imposed by a warming climate. 

Determinants of geographic variation in woodpecker species richness worldwide (Piciformes: Picidae)

Ilsøe, Sigrid, 24.10.2014

Abstract:
Large-scale spatial variation in bird species richness is influenced by both contemporary drivers (e.g. habitat availability, climate and human influence), and long-term dynamics (Quaternary climate changes, deep-time habitat availability and biogeographic region). Due to their well-known distributions, many birds are good model systems for testing biogeographic hypotheses on groups with specific morphology and ecology. One such group is the woodpeckers, which are found in woody habitats almost worldwide. Their morphology and ecology reflect their arboreal life, making them useful when studying broad-scale drivers of avian species richness. However, broad-scale studies on woodpecker species richness are missing. We used species distribution maps of all woodpecker species, overlaid onto a cylindrical equal area grid of 1° × 1° resolution to study geographical variation in woodpecker species richness worldwide. Influences of potential determinants were analysed using Ordinary Least Square (OLS) regression models and Spatial Simultaneous Autoregressive (SAR) error models. Mean tree cover showed a strong positive effect on woodpecker species richness, which highlights the close association between woodpeckers and trees, but also indicates that woodpeckers are found in all kinds of woody habitats worldwide. Current climate also showed a marked positive effect on woodpecker species richness, emphasizing the importance of water-energy availability.

The influence of free-ranging dogs on the native wildlife populations in the Mara North Conservancy, Masai Mara

Jensen, Nicolai Elmo, 24.10.2014, speciale

Habitat selection of the common dormouse Muscardinus avellanarius in Denmark

Mortensen, Rasmus Mohr, 01.10.2014, speciale

Behavioural response of roe deer (Capreolus capreolus) to simulated wolf and lynx presence

Jensen, Trine Munck, 15.09.2014, speciale

Distribution of adaptive genetic variation at the phenotypic and genotypic level in the threespine stickleback: From saltwater to freshwater

Pedersen, Susanne Holst, 29.08.2014

Abstract:
Adaptive divergence between marine and freshwater populations of the the threespine stickleback (Gasterosteus aculeatus) has attracted much interest as a model of contemporary and parallel evolution. Body armour is often reduced when sticklebacks adapt to freshwater, and changes in body shape also take place. These two traits have evolved in parallel in many freshwater environments. However, in freshwater environments in connectivity to the open sea, adaptive divergence between freshwater and marine sticklebacks is not always evident, indicating that gene flow is counteracting local adaptation. In the present study, we sampled threespine sticklebacks continuously along the Odder River that is connected to the Norsminde Fjord, representing a freshwater-marine environmental gradient. We analyzed 96 SNPs, and the indel marker Stn381 in the Eda gene, a major quantitative trait locus affecting lateral plate number, along with body armour, body shape, parasite infestation and other phenotypic traits. The distribution of genetic and phenotypic variation were analyzed and quantified using cline analysis, spatial autocorrelation along with measures of genetic differentiation and tests for homogeneity and allele frequencies. Fine-scale genetic structure was revealed by spatial autocorrelation. However, low genetic differentiation (overall FST = 0.0069, and highest pairwise FST of 0.0133) between the three major groups (the upstream, downstream and marine group) and detection of only a single group of individuals using Bayesian cluster analysis indicated presence of high gene flow in the system and no clear hybrid zone dynamics. However, selection was detected at molecular markers and phenotypic traits, but changes occurred gradually rather than abruptly. The Eda gene, determining number of lateral plates, was the strongest outlier among molecular markers. The lateral plate-morph distribution only changed gradually, and the fully-plated morph was dominant at all sites, although an upstream-directed increase of the low-plated morph was detected. Body shape differed significantly between the three major groups, with marine sticklebacks being characterized by more lateral plates, larger size, thinner heads, smaller body depth, and the freshwater sticklebacks being characterized by fewer lateral plates, smaller size, deeper bodies and larger heads. Overall, divergent selection does occur but seems to be constrained by high gene flow in this system.

Undersøgelse af vegetationsdynamikken i danske klitheder fra 1995-2010 ved brug af ortofotos

Hansen, Lærke Glerup, 22.08.2014

Abstract:
Danmark besidder naturligt en stor andel af Europas klitheder, og disse er beskyttet af internationale konventioner. Klithedeøkosystemet er karakteriseret ved at være en mosaik af en række forskellige vegetationstyper, der udvikler sig og interagerer både i tid og rum.

Dette studie fokuserer på at anvende en GIS-baseret metode til at monitorere dynamikken i klithedelandskabet i det nordvestlige Jylland over en periode på 15 år. Et ortofoto fra 2010 blev inspiceret visuelt og opdelt i forskellige habitattyper på baggrund af forskelle i farver og grynethed. De enkelte habitattypers artssammensætning samt dækningsgrad af laver, mosser og højere planter blev herefter undersøgt i felten. I alt kunne fire vegetationstyper erkendes; 1) klithede, 2) dværgbuskdomineret fugtig klitlavning, 3) halvgræsdomineret fugtig klitlavning og 4) grå klit.

Disse fire vegetationstyper kunne adskilles på baggrund af forskelle i arternes præference for de fem Ellenberg indikatorværdier F (fugtighed), L (lys), R (reaktion - pH), S (salt) og N (kvælstoftilgængelighed).

Dynamikken mellem de fire vegetationstyper blev herefter undersøgt ved at sammenligne ortofotos inden for en 15-årig periode (1995-2010). Resultaterne viste, at den grå klit i denne periode blev reduceret med ca. 50 %. Dette indikerer, at den dværgbuskdominerede klithede generelt øger sin dækningsgrad, hvilket blandt andet kan skyldes en øget kvælstofdeponering. Desuden viste resultaterne, at den halvgræsdominerede fugtige klitlavning også øger sin totale dækningsgrad, hvilket kan skyldes en stigning i årligt nedbør eller lukning af dræn i området.

Selvom den anvendte metode er tidskrævende og endnu ikke udviklet til forvaltningsmæssigt brug, er resultaterne alligevel lovende og metoden kan med tiden blive mere anvendelig til at studere dynamikken i mosaikprægede vegetationstyper. Resultaterne viser tydeligt, at forvaltningsmæssige tiltag er nødvendige for at bevare den grå klit og genskabe den naturlige dynamik på klitheden langs den jyske vestkyst.

Evolution of the tripartite symbiosis between earthworms, Verminephrobacter and Flexibacter-like bacteria

Kristensen, Peter Møller, 31.07.2014

Abstract:
The presence of bacteria within the excretory organs - the nephridia - of lumbricid earthworms (Lumbricidae) have been recognized for almost a century. Studies on this symbiosis have been intensified during the last decade, but the function of the symbionts is still a conundrum. Today, we know that individual earthworm species possess a variety of symbionts in different combinations,
but Verminephrobacter and Flexibacter-like bacteria are among the most common. Verminephrobacter is today known to be monophyletic, species-specific, itness-increasing and vertically transmitted from parents to offspring. All of these aspects make this symbiosis a candidate of potential coevolution and -speciation of the symbiotic partners since the most recent common ancestor of lumbricids about 100 million years ago. The transmission mechanism of Flexibacter-like symbionts is currently unknown, but indications of monophyly and species-specificity presumably point towards a similar degree of shared evolution. Previous studies have shown that Verminephrobacter show signs of cospeciation among lumbricids, but only among closely related host species. What happens at an intergeneral or -familiar level remained unsolved, due to a
very low phylogenetic resolution of the hosts - and what patterns are found in the phylogeny of Flexibacter-like bacteria is completely unclarified. The present study demonstrates the proposed host species-specificity of Flexibacter-like symbionts. Indications of cospeciation between hosts and both symbionts were however hard to reveal through cophylogenetic analyses, due to a recurring low level of resolution in the host phylogeny. The findings from the previous study, regarding Verminephrobacter, were however reproduced. The resolution of the Flexibacter-like symbiont phylogeny showed resolution levels comparable to the host phylogeny. In spite of the poor resolution, this phylogeny demonstrated the presence of polyphyletic Flexibacter-like strains
in individual host species. This is indicative of multiple events of horizontal transfer, where Flexibacter-like symbionts are transferred between closely or distantly related earthworms, followed by adaptation to the new environment. The mechanism behind this is currently unknown, but it is presumed to be carried out by some sort of vector or during putative attempts of hybridization
between hosts. Future constructions of better resolved phylogenies of earthworms and Flexibacter-like symbionts will provide a deeper understanding of the evolutionary relationship. The fact that incongruences are evident already in the poorly resolved trees in this study, predicts an immeasurable meshwork of horizontal transfer of symbionts

Kan fødetilgængeligheden være en mulig begrænsende factor for vandremuslingens spredning i Gudenåen?

Andersen. Sara, 15.07.2014, speciale

Hvad bestemmer dækningen af klokkelyng (Erica tetralix) på våde heder?

Lykke, Irene Marietta Østergaard, 07.07.2014, speciale

A global geospatial assessment of potential areas for rewilding with wild horses (Equus ferus).

Naundrup, Pernille Johansen, 26.06.2014

Abstract:
Background: During the late Pleistocene and early Holocene the majority of the megafauna in the Americas and Eurasia were extirpated by anthropogenic factors. Many of the species were keystone species and their absence has a large effect on ecosystems and ecosystem services world-wide. Closely related species can serve as proxy for extinct keystone species and be used in the rewilding of ecosystems.
Methodology: In this study I used habitat suitability models to assess the climate sensitivity of feral, semi-feral and wild populations of the horse (Equus ferus). These models were combined with knowledge of habitat selection in feral and semi-feral domestic horse (Equus ferus caballus) and free-ranging Asiatic wild horse (Equus ferus przewalskii) to identify areas suitable for rewilding with E. f. caballus as a proxy for its wild ancestor (Equus ferus ferus) within its former range. Information on location and management of populations of feral and semi-feral E. f. caballus and wild E. f. przewalskii was gathered from governmental agencies, researchers and NGOs world-wide. Locations were linked to data on climate using two habitat suitability modelling techniques. Mean temperature in coldest quarter, precipitation in coldest quarter and precipitation in driest quarter seems to be the best predictors of climatic constrain on the distribution of feral and semi-feral E. ferus. The habitat suitability models did, however, fail to identify suitable climate in Siberia which constituted a large part of the former range of E. ferus. This was most likely due to geographical anthropological bias in the current distribution of populations and in the available information on feral and semi-feral populations of E. f. caballus. A combination of the habitat suitability models and identification of areas with suitable habitat revealed large areas suitable for rewilding with E. f. caballus with in the former range of the species, including five areas already under rewilding.
Conclusions: Using habitat suitability models is an important tool in conservation management, but knowledge of how data is collected and possible geographical biases is important to evaluate the output of the models. Combining habitat suitability models and knowledge of the ecology of a species can be vital in the identification of areas suitable for rewilding with a species.

Enzymatisk nedbrydning af risstrå

Willink, Fillip Wolfgang, 25.06.2014

Abstract:
This master thesis is part of a Danida funded demonstration project in Vietnam, where the possibility of using alternative waste plant materials as substrate in small local biogas plants is investigated. As for now only pig manure is used in the biogas plants, which is much easier degraded then the lignocellulosic plant materials. The aim of this thesis was to investigate a possible pretreatment of rice straw with enzymes from the claimed cellulolytic facultative anaerobic bacterium Cellulomonas uda. This was done through four lab experiments. 1) The capability of extracellular cellulase enzymes from C. uda to hydrolyze α-cellulose and rice straw was investigated and compared to commercial enzymes. 2) The effect of the rice straw size on the hydrolysis was compared. 3) The fermentation products under anaerobic conditions was analyzed. 4) The production of cellulase under aerobic and anaerobic conditions was investegated. The filter paper activity of the supernatant from C. uda was found to be 0,035

Investigation of Anhedonia in farm mink

Schou, Toke Munk, 20.06.2014

Abstract:
The housing conditions on mink farms and the minks’ reaction to the environment indicate that some farmed mink may experience stress of an intermittent type for longer periods. However there is a lack of indicators of intermediate chronic stress in farm mink. Psychological and physical chronic stress has shown to increase the risk of developing depression and disease for both humans and animals. Because of the similarity of depression symptoms between animals and humans, an animal model of depression has been developed for rodents. With the use of a chronic unpredictable mild stress paradigm (CMS) depression can be elicited in rodents. Anhedonia (defined as: a decreased capacity to experience pleasure of normal rewarding stimuli) is one of three core symptoms of major depression and is used a indicator of elicited depression in rodents. Anhedonic rodents have a reduced rewarding sensitivity when examining normally rewarding stimuli such as sweet solutions. The reduced rewarding sensitivity cause reduced rewarding value of the substances, which is measured by reduced preference or consumption rate. Further, several studies have examined side effects of anhedonia e.g. reduced exploration, reduced aggression, reduced sexual activity, reduced weight, increased conflict behaviour and increased craving-like behaviour. The aim of this study was to develop a similar method of measuring anhedonia in farm mink. Thus this thesis is divided into two sections: 1) investigating substances that mink find rewarding for use in an anhedonia test; 2) Investigating anhedonia in farm mink.

     1) With the use of a Two-bottle choice test minks’ ability to taste and the rewarding value of sucrose solutions were examined. Two tests were carried out. In the first test the rewarding value of 0.5M sucrose to plain water was tested. The first test found a preference of 60% for sucrose, which is the first time that the minks’ ability to taste sucrose has been documented. The second test did not find any preference between 0.125M, 0.25M and 0.5M to plain water. Thus, the rewarding value of sucrose was not found stable enough for use in an anhedonia test. An additional rewarding test was performed by testing the rewarding value of manipulated farm feed (MFF) and wet cat feed (WCF). The rewarding value was measured as consumption rate. The mink females found WCF 26.8% more rewarding compared to the MFF. The rewarding values were found useable for an anhedonia test.

    2) With the use of several well-known welfare assessment procedures and the rewarding value of WCF and MFF a test for the occurrence of anhedonia in farm mink was developed and carried out. The test did not find that dams with high kit loss (used as a measure of pre-pregnancy and prenatal stress) were in greater risk of having anhedonia in comparison with dams with a total kit survival. In addition a correlation test was performed. Mink females with low body weight were found to show signs of anhedonia with positive correlations for the following four measures: 1) decreased consumption rate; 2) decreased exploration; 3) decreased aggression; 4) increased conflict behaviour (in the Stick test). Thus, these variables were – as expected – correlated for anhedonic mink females as found in rodents. However some conflicting correlations were also found as consumption rate was positively correlated with craving-like behaviour and conflict behaviour in the Novel Object test. These results indicate that there is a potential and a need for further investigation and development of an anhedonia test for farm mink. The need of an anhedonia test has been emphasized in the WelFur protocol for farm mink as a positive emotional state is one of 12 welfare assessment criteria (Mononen et al. 2012), which is affected by an animal’s depressive state.

Identification and characterisation of a biofilm negative bacillus cereus transposon mutant

Rasmussen, Mathilde Greve, 12.06.2014, speciale

Gymnasielærere og formidlingsinstitutioners overvejelser i forhold til inddragelse af det uformelle læringsmiljø i gymnasiets biologiundervisning

Laursen, Mai-Britt, 27.06.2014, speciale

Personalities of the solitary and social spider species Pisaura mirabilis and Stegodyphus dumicola

Klange, Signe, 29.04.2014, speciale

Morphology and ontogeny of the pectines of Babycurus jacksoni (Scorpiones: Buthidae) with a comparison of presumed sensory structures in juvenile xiphosurans

Thybring, Mette, 11.04.2014

Abstract:
The unique mechano- and chemosensory organ of scorpions, the pectines, have been studied intensively. However, studies on the ontogeny of the pectines has received little attention. This study will focus on the ontogeny and morphology of the pectines from first instar through all juvenile stages to adult in the scorpion Babycurus jacksoni. Pectines are a pair of ventral comb-like sensory structures with marginal and medial lamellae which carry numerous pectinal teeth with ventral microscopic sensory pegs. Size and morphology of exuvia and their pectines from different instars of B. jacksoni were compared and wholemounts and sectioned material of the pectines were studied with light microscopy. Scanning electron microscopy (SEM) was used to study the presumed sensory organs in greater detail. Low dose X-ray CT-scanning was used to make 3D models of B. jacksoni. A significant correlation between pectine length and instar (P < 0.0001) was shown for B. jacksoni. The correlation of the proportion pectine length divided by carapace length (LPmean/CL) with instar was not significant (P = 0.4171), indicating isometric pectine growth. The ontogeny of pectines and their morphological changes were investigated. The sensory pegs on the first instar were not fully developed and probably not yet functional. Sensory pegs on the pectines were concentrated in peg fields and increased in average number per tooth from 282 in second instar to 703 in fifth instar. In the adult scorpion, pegs were 10 µm long and 2 µm wide. Cuticular projections in the form of spines surrounded the peg field with a density of 25 pr. 100µm2. Such fields of spines have not been observed near the peg field before. The morphology of presumed sensory structures on the ventral side of two species of juvenile horseshoe crabs (Xiphosura) were studied with SEM, and compared with the sensory structures in B. jacksoni. The horseshoe crabs had simple and serrated setae of different lengths with denticles of various sizes in different positions. Various kinds of pores with unknown function were found ventrally. Funnel pores were only found in Tachypleus gigas. Limulus polyphemus had a low number pr. square unit of setae compared to T. gigas, but this could be explained by age differences as setae density are known to increase with age. The setae morphology were compared to ones found in Crustacea and Pycnogonidae. Crustaceans were found to have more types of setae than the horseshoe crabs. Pycnogonids had both bifurcate and trifurcate setae not found in horseshoe crabs. Presumed sensory organs in scorpions and horseshoe crabs showed different morphologies. Serrated setae were only observed in horseshoe crabs along with numerous pores not associated with setae. Neither of these features were observed in scorpions. Strain-receptors, called slit sense organs, and the specialized hair like mechanoreceptors, trichobothria, similar to those found in for example spiders were observed in scorpions, but not in the horseshoe crabs. Even though the horseshoe crabs and scorpions has a recent common ancestor this does not appear to result in homologue sensory setae.

Habitat selection of a small herd of European bison (Bison bonasus) in Denmark

Olsen, Joanna Birch, 14.03.2014

Abstract:
Several herds of European bison live around Europe under wild and semi-wild living conditions. Further conservation management actions are needed to ensure the long-term survival of the species, and more suitable habitats are needed for reintroduction. In Denmark only two small semi-wild herds are present, and further studies could help find other suitable locations in the country. To do this, more study of habitat selection is needed as well as a study of the effect that environmental conditions have on the activity patterns of bison, as well as the effect the grazing of bison can have on keeping areas open.
This study took place in part of the Gudenå River valley, Vorup Enge in Denmark. A herd of 11 European bison is kept under semi-wild conditions. The study is focused on the habitat selection in relation to the habitat availability, the behavior patterns over a summer and their daily routine. Several environmental parameters, as different habitat types, hydrology of soil, food quality and topography, were included in linear regression models to test the effect on frequency, and logistic regression models was conducted to test the effects on presence/absence. Data on the herd was gathered by observing the herd over a summer period.
The herd preferred open areas over forest areas and had similar diurnal activity patterns as observed by previous studies. Topography of terrain emerged as the main determinant of bison habitat usage, with the low lying areas being less used, while other parameters have limited explanatory support. Leaf area has some explanatory support on frequency, while field habitat and wetness has some explanatory support on presence/absence.

Driftshistoriens betydning for naturtilstanden på sure overdrev i Danmark - sure overdrev i Danmark

Damgaard, Stinna Camille Catharina, 14.02.2014, speciale

Effekter af kvælstofdeponering og græsning pa overdrevsplantesamfund med fokus pa eventuelle tidsforsinkelser - Målt ved gennemsnitlige indikatorværdier

Kamp, Anne Trabjerg, 20.12.2013, speciale

Phylogeographic Analysis of Apodemus Flavicollis in Northwestern Europe

Brummerstedt, Maria Stenbye, 19.12.2013

Abstract:
The aim of the study was to determine the phylogeography and population structure of the Yellow-necked mouse (Apodemus flavicollis) in north-west Europe, using 13 microsatellite markers and mtDNA D-loop markers. In the study a pronounced and stable population structure was found among the sample locations, with only few populations showing signs of expansion. The phylogenetic analysis showed close relationship between eastern localities and between central and northern localities, indicating that Europe was probably colonized by at least three colonization routs and that the colonization of Denmark occurred through two different routes; One route originating from the Urals in the east heading west through Russia, Estonia and Latvia and from here to the southern Danish islands. The other route originating in the south, through central Europe to the Peninsula Jutland. Estimations of time since range- and population expansion showed signs of correlation with longitudes and latitudes.

Group size effects on energy and water conservation in the social spider Stegodyphus dumicola

Bruun, Anne Vestergaard Druedahl, 17.12.2013, Speciale

Compensating for the Consequences of Group-living in the Cooperative Spider Stegodyphus dumicola

Soydaner, Ayşe Lale, 16.12.2013, speciale

Firben på små øer: En netværksanalyse

Enoksen, Camilla Aviaaja, 29.11.2013, speciale,

190,000 years of climate change in Europe: avifaunal responses and vegetation implications

Holm, Sandra, 28.11.2013

Abstract:
Providing an underutilized source of information for paleoenvironmental reconstructions, birds are rarely used to infer paleoenvironments despite their well-known ecology and extensive Quaternary fossil record. Here, we use the avian fossil record to investigate how Western Palearctic bird assemblages and species ranges have changed across the latter part of the Pleistocene, with focus on the links to climate and the implications for vegetation structure. As a key issue we hereby address the full-glacial presence of trees in Europe north of the Mediterranean region, a widely debated issue with evidence for and against emerging from several research fields and data sources. We compiled and analyzed a database of bird fossil occurrences from archaeological sites throughout the Western Palearctic and spanning the Saalian-Eemian-Weichselian stages, i.e. 190-10 kya BP. In general, cold and dry-adapted species dominated the Late Pleistocene fossil assemblages, with clear shifts of northern species southwards during glacials, as well as northwards and westwards shifts of open-vegetation species from the south and east, respectively, and the downwards shifts of alpine species. A direct link to climate was clear in Northwestern Europe, while in general, vegetation changes showed the strongest association with bird assemblages and this makes them useful for inferring woodland characteristics of past landscapes. Forest-adapted birds were found in continuous high proportions throughout the study period, providing support for the presence of trees north of the Alps during the full-glacial stages. Furthermore, the results suggest forest-dominated but partially open Eemian landscapes in the Western Palearctic as well as in the Northwestern European subregion.

Bacterial Symbionts within the Scalidophora: Candidatus Tenuiformis priapulorum gen. nov, sp., nov., a novel symbiotic bacterium living in the gut of Priapulus caudatus

Kroer, Paul, 11.07.2013

Abstract:
Priapulus caudatus is a marine predatory worm of the small phylum Priapulida. Since the Cambrian P. caudatus has changed little morphologically compared to its ancestors and has become a living fossil. However, today the intriguing benthic worm seems to maintain a stable cosmopolitan distribution. This study has discovered a novel, highly elongate and symbiotic bacterium in the midgut of P. caudatus, closely associated with microvilli. This bacterium is a member of the order Rickettsiales (α-proteobacteria), an order of important intracellular symbiotic bacteria. The symbiont is, unlike the majority of the Rickettsiales, extracellular and clusters with probable extracellular symbionts of arthropods. This study reveals a well-defined, novel clade consisting of ectosymbiotic gut bacteria of the Ecdysozoa. This symbiont is likely important for P. caudatus and should be considered in future investigations concerned with the ecology of the worm. The bacterium represents both a new species and a new genus and is tentatively named Candidatus Tenuiformis priapulorum.

Effect of stress on reproduction in farmed male mink (Neovison vison) -behavioural and hormonal traits characterising male mink reproductive success

Andersen, Nathalia Hauberg, 21.05.2013, speciale

The imprint of Extinction on Phylogenetic Community Structure

Plum, Christoffer Milo, 01.05.2013

Abstract:
Extinction processes are an essential part of evolution, pruning and sorting taxa when conditions no longer favour their existence. Eventually, all taxa will have experienced the forces of natural selection, and either evolved into something completely new or ceased to exist entirely.
Knowledge of how extinction processes affect community structure at the phylogenetic level, will greatly enhance our understanding of why communities have the composition and structure that we see today, and help us predict how they may change in the future. The discrepancy of tree genera between the temperate forest zones of the Northern Hemisphere is a well known phenomenon, with Europe being significantly less taxonomically diverse than North America and Asia, despite sharing a similar climate and fossil record.
This study is the first to analyse the imprints of extinction on the phylogenetic structure of regional communities, caused by a broad scale extinction event, by investigating the changes in Northern Hemisphere tree communities before and after the Plio/Pleistocene cooling events. By using phylogenies of the Tertiary temperate forest communities of Europe, Asia, Eastern and Western North America, and calculating the Net Relatedness Index (NRI) and Mean Pairwise Phylogenetic Distance (MPD) of these in relation to the contemporary communities of the same regions, it was possible to correlate these to the extinction of genera within the regions.
The study shows a clear correlation between clustering within community structure and the proportion of extinct genera, proving that extant genera of this extinction event are clustered within specific taxonomic clades. These results show, that extinctions leave a selective imprint on phylogenetic community structure, and this can have a profound importance to conservation efforts, if used to determine how or if threatened species and communities of today are already exhibiting similar patterns in the face of climate change and human influence.

Effekten af indavl på kuldstørrelse: En undersøgelse af racekatten Europé foretaget på tre populationer i Norden

Køhler, Eva, 19.04.2013, speciale

An Ecological Network Analysis of Las Canadas

Hemdorff, Jakob, 12.04.2013, speciale, appendix I, Appendix II, appendix III

Potential effect of climate change on the distribution of allergenic ragweeds (Ambrosia spp.) in Europe

Rasmussen, Karen, 22.03.2013, speciale

Vegetationsudvikling i en dansk urørt skov (Bolderslev Skov) over en periode på 11 år Iben

Knudsen, Iben, 12.04.2013, Speciale

Koloni-etablerende humlebidronningers (Bombus canariensis) adfærd på landskabsniveau

Henriksen, Marie Vestergaard, 15.02.2013, speciale

Betydningen af skarvers individuelle variation i adfærd for præcisionen af overlevelsesestimater

Gassner, Ann Britt, 02.07.2012, speciale

Determinants of the distribution ranges of eleven economically important palm species in western South America

Sørensen, Mia Vedel, 12.06.2012, speciale

Habitatgrænsers påvirkning på bestøvningsnetværk

Pedersen, Nanna Maria Elgaard, 08.06.2012, speciale

Habitat-præferencer for rødrygget tornskade (lanius collurio) i nationalpark Mols Bjerge

Svendsen, Jannie Kalør, 08.06.2012

Abstract:
Rødrygget tornskade er i tilbagegang i hele Europa, og figurerer nu på EU Fugle Direktivets bilag I, som indeholder sårbare fuglearter, der yngler i Europa. En af årsagerne til tilbagegangen menes at være tab af ynglehabitat. For at kunne vende denne tendens ved hjælp af bedre habitat forvaltning, undersøgte vi habitat- og redested-præferencer for rødrygget tornskade i Nationalpark Mols Bjerge, Danmark, et vigtigt yngleområde for arten i Danmark. I alt blev 28 reder fundet i 2010 og 2011. For at bestemme redested-præferencer blev den vegetative komposition i krat anvendt som redested, sammenlignet med kompositionen i det nærmeste ikke anvendte krat vha. Multi Response Permutation Procedure (MRPP). Til at undersøge habitat-præferencer, blev en Resource Selection Probability Function (RSPF) modelleret med de 28 reder og 280 pseudo absence punkter fordelt over hele studieområdet, og den bedste model blev bestemt vha. informations-teoretisk modelselektion. Krat, anvendt som redested, indeholdt signifikant mere slåen Prunus spinosa end det nærmeste krat. RSPF viste, at tilstedeværelsen af rødrygget tornskade var positivt korreleret med vegetations heterogenitet og topografisk fugtighed, og at der ikke var en korrelation med afstanden til nærmeste vej eller sti. Slåen-rige krat, og tornede krat generelt, er i flere studier fundet som vigtige redesteder for rødrygget tornskade. Sådanne krat er ofte meget tætte i vegetationen, hvilket yder beskyttelse mod prædatorer. Et heterogent habitat giver gode jagtbetingelser for rødrygget tornskade, som jager insekter og andet, som den spotter i lav vegetation fra højere og enkeltstående buske, krat og træer. Præference for højt topografisk fugtighed kan være et udtryk for større fødetilgængelighed i sådanne område, da rødrygget tornskade jager tæt ved reden. Vi fandt ingen sammenhæng mellem redested og afstand til nærmeste sti eller vej, hvilket er et positivt resultat for nationalparken, da rødrygget tornskade formentlig ikke vil være genereret af en øget færdsel i området. Rødrygget tornskade i Mols Bjerge bygger rede i slåen-rige krat og foretrækker habitat med heterogent vegetation og høj fugtighed nær redestedet. Til gengæld, er der ikke noget som tyder på, at menneskelig forstyrrelse har nogen indflydelse på dens habitat valg.

Lattergasdannelse i jord ved vandmætning og gylletilførsel

Bundgaard, Janne, 25.05.2012, speciale

The impact of bacterial infection on survival in Drosophila melanogaster

Henten, Anne Marie Vestergaard, 13.04.12, speciale

Reproductive biology in the blind shark, Brachaelurus waddi, with notes on feeding biology and habitat use

Pedersen, Anne Foged, 13.04.12, speciale

Emission af CO2 og CH4 og fosforfrigivelse fra oversvømmet landbrugsjord i Filsø - en laboratorieundersøgelse

Møller, Karsten Dollerup, 20.03.2012, specialefileadmin/bioscience/Documents/2012-03-20_Speciale_Karsten_Dollerup_Moeller.pdf

Acclimation increases the efficiency of the aphidophagous coccinellid predator Adalia bipunctata on aphid pests

Sørensen, Christian Hougaard, 08.03.2012, speciale

Nesting behaviour in domestic hens (Gallus gallus domesticus): Does increased heterogeneity in nest boxes reduce gregarious nesting?

Clausen, Tina, 07.02.2012

Abstract:
Nesting behaviour is fairly similar in jungle fowl (Gallus gallus) and commercial layers (Gallus gallus domesticus) but restricted space and nest boxes have resulted in unwanted behaviours such as gregarious nesting, where a hen selects an already occupied nest box even though other nest boxes are available. This may pose a financial cost to the keeper and reduce animal welfare. It has been suggested that gregarious nesting may be caused by the difficulties experienced by hens in distinguishing between nest boxes in the long rows of identical nest boxes. Heterogeneity in nest boxes could therefore reduce gregarious nesting. To test this hypothesis two experiments were performed. For each experiment 12 groups of 13-15 ISA Warren hens were housed in pens with three adjacent nest boxes. In the first experiment six experimental groups were provided with three different appearing nest boxes and in the second experiment six experimental groups were provided with three different nesting materials. In both experiments six control groups were provided with three identical nest boxes with wood shavings as nesting material. Daily egg collection and video recordings were performed for eight and seven days, respectively. The proportion of gregarious nesting was higher in experimental groups compared to control groups (P < 0.01). Furthermore, occupied nest boxes were selected more often in experimental groups compared to control groups (P < 0.01). Number of visits to and eggs laid in nest boxes positioned either left or right were higher compared to nest boxes positioned in the middle in both the experimental groups and control groups (P < 0.05). Number of visits to and eggs laid in nest boxes with yellow walls or standard nest boxes were higher compared to nest boxes with black plastic flaps in front (P < 0.05). Furthermore, straw was preferred with regard to number of visits to and eggs laid in nest boxes compared to both wood shavings (P < 0.01) and peat (P < 0.01) as nesting materials. The pre-laying period did not differ between the experimental and control groups (P > 0.05). Heterogeneity in nest boxes in present experiments did not reduce occurrence of gregarious nesting. Instead, the combination of preference for nest box position, appearance, and nesting material, indicate that hens shared preferences for nest boxes positioned at the ends, yellow walls, standard nest boxes, and straw as nesting material. Therefore it is suggested that nest boxes positioned in the middle should be made more attractive for egg layers by providing preferred nesting materials, nest box appearances, or by providing single nest boxes instead of rows, thereby possibly reducing gregarious nesting.
Keywords: Domestic hens; Nesting behavior; Gregarious nesting; Preferences.

Development and credibility testing of individual-based models, simulating the predatory pressure of the domestic cats (Felis catus)

Hansen, Jannick, 25.01.2012, speciale

Anvendelse af forskellige typer af træflis som kulstofkilde for denitrifikation i konstruerede minivådområder

Bruun, Jacob Druedahl, 25.11.2011, speciale

Optimizing the captive welfare of zoo housed animals – A review
&
Environmental enrichment in stimuli-poor and in stimuli-rich housed black-footed cats, Felis nigripes

Nielsen, Sofie L. H., 07.11.2011, speciale del 1 og speciale del 2

Measurements of leaf area index and relation to transpiration in energy willow

Sørensen, Helle Baadsgaard, 24.10.2011, speciale

Bundling Ecosystem Services: Trade-offs and Synergies in a Cultural Landscape

Turner, Katrine Grace, 30.09.2011, speciale

Studie af urtevegetationens artsudskiftning i overgangen fra læhegn til mark med fokus på økologisk og konventionel driftstype

Damgaard, Lene Schelde, 13.09.2011, speciale

Molekylær Patogenese ved Reaktiv Artrit

Carlsen, Thomas Gelsing, 28.08.2011, speciale

The effects of fish farming on nitrogen cycling in a tropical estuary

Nguyen, Kim Hanh, 23.08.2011, speciale

A super?network approach to the complexity of nature: Crossing scale and habitat borders

Kromann-Gallop, Lea, 15.07.2011, speciale

Ammoniaktoksicitet hos fisk – forskelle i tolerance og udskillelsesstrategier mellem vandåndere og luftåndere

Jensen, Anders Ejlskov, 08.07.2011

Abstract:
Ammonia is produced by all animals during the catabolism og amino acids. Because of its toxic nature continuous excretion is necessary to prevent build up in tissues. Fish excrete ammonia primarily as NH3 across the gills down a steap concentration gradient. Amphibious airbreathing fish cannot excrete ammonia across the gills during aerial exposure, so alternative excretion and detoxifying mechanism are used. Lower protelysis and amino acid catabolism, partial amino acid catabolism to alanine, synthesis og glutamine and urea production by the onithine-urea cycle are some strategies utilized by airbreathing fish to prevent an internal rise in ammonia levels. According to the available literature a higher tolerance towards ammonia exists in airbreathing fish compared to strict waterbreathers. Whether this is a general trend for all airbreathers (facultative and obligate), remains to be investigated. Apart from airbreathing, from an evolutionary standpoint, urea production through the ornithine-urea cycle played a vital role in the colonization of the terrestrial environment.

Forest Edge Contrasts have a predictable Effect on the Spatial Distribution of Carabid Beetles in Urban Forests

Noreika, Norbertas, 20.06.2011, speciale

Ecological genetics of sociality in eiders (Somateria mollissima)

Noreikienė, Kristina, 20.06.2011, speciale

Konkurrenceforhold og rumlig fordeling af skovbundsplanter i bøgeskov

Tangø, Emma Line, 17.06.2015, Speciale

Randeffekter på biodiversitetsmønstre i danske bøgeskove

Barild, Ditte Grube, 15.06.2011, speciale

Bekæmpelse af Rynket rose (Rosa rugosa) i sårbare naturtyper

Boesen, Mathilde, 20.05.2011, speciale

Evolutionary Consequences of Hybridization in a Climate Change Context

Krag, Kristian, 13.02.2009, speciale

Bakteriel sulfatreduktion i procesvand fra en papirfabrik

Svendsen, Asbjørn, 04.09.2008, speciale

Karakterisering af en anaerob termofil cellulosenedbrydende bakteriekultur fra en papirfabrik

Jørgensen, Maria Giltoft, 30.04.2008, speciale

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