@phdthesis{Teckentrup2019, author = {Teckentrup, Lisa}, title = {Understanding predator-prey interactions}, doi = {10.25932/publishup-43162}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431624}, school = {Universit{\"a}t Potsdam}, pages = {ix, 133}, year = {2019}, abstract = {Predators can have numerical and behavioral effects on prey animals. While numerical effects are well explored, the impact of behavioral effects is unclear. Furthermore, behavioral effects are generally either analyzed with a focus on single individuals or with a focus on consequences for other trophic levels. Thereby, the impact of fear on the level of prey communities is overlooked, despite potential consequences for conservation and nature management. In order to improve our understanding of predator-prey interactions, an assessment of the consequences of fear in shaping prey community structures is crucial. In this thesis, I evaluated how fear alters prey space use, community structure and composition, focusing on terrestrial mammals. By integrating landscapes of fear in an existing individual-based and spatially-explicit model, I simulated community assembly of prey animals via individual home range formation. The model comprises multiple hierarchical levels from individual home range behavior to patterns of prey community structure and composition. The mechanistic approach of the model allowed for the identification of underlying mechanism driving prey community responses under fear. My results show that fear modified prey space use and community patterns. Under fear, prey animals shifted their home ranges towards safer areas of the landscape. Furthermore, fear decreased the total biomass and the diversity of the prey community and reinforced shifts in community composition towards smaller animals. These effects could be mediated by an increasing availability of refuges in the landscape. Under landscape changes, such as habitat loss and fragmentation, fear intensified negative effects on prey communities. Prey communities in risky environments were subject to a non-proportional diversity loss of up to 30\% if fear was taken into account. Regarding habitat properties, I found that well-connected, large safe patches can reduce the negative consequences of habitat loss and fragmentation on prey communities. Including variation in risk perception between prey animals had consequences on prey space use. Animals with a high risk perception predominantly used safe areas of the landscape, while animals with a low risk perception preferred areas with a high food availability. On the community level, prey diversity was higher in heterogeneous landscapes of fear if individuals varied in their risk perception compared to scenarios in which all individuals had the same risk perception. Overall, my findings give a first, comprehensive assessment of the role of fear in shaping prey communities. The linkage between individual home range behavior and patterns at the community level allows for a mechanistic understanding of the underlying processes. My results underline the importance of the structure of the landscape of fear as a key driver of prey community responses, especially if the habitat is threatened by landscape changes. Furthermore, I show that individual landscapes of fear can improve our understanding of the consequences of trait variation on community structures. Regarding conservation and nature management, my results support calls for modern conservation approaches that go beyond single species and address the protection of biotic interactions.}, language = {en} } @phdthesis{Hoffmann2021, author = {Hoffmann, Julia}, title = {Influence of artificial light at night on the behavior of small mammals}, school = {Universit{\"a}t Potsdam}, pages = {115}, year = {2021}, abstract = {Artificial light at night (ALAN), one form of human-induced rapid environmental change, is continuously spreading in space and time and increasing in intensity as part of the ongoing urbanization. A vast range of animals is known to be affected by ALAN as, among other things, it can mask natural light cues and change both the perceived as well as the actual predation risk. Since ALAN per se is restricted to the night, the majority of studies so far have focused on nocturnal species or behavioral changes during the night. How polyphasic species respond to ALAN has been largely overlooked, although they can possibly carry over effects of nighttime illumination into the day. Additionally, individuals within a species are known to consistently differ in their personality which includes risk-taking behavior. While this implies that ALAN can lead to varying anti-predatory responses in animals within a population, knowledge on this topic is still very limited. This thesis aims at investigating what initial behavioral reaction is caused by ALAN in polyphasic small mammals while also incorporating an animal's personality. Nighttime and daytime activity, movement and foraging behavior of the bank vole (Myodes glareolus) were investigated in regards to effects of different light intensities and partial illumination in the laboratory. Additionally, changes in intra- and interspecific interactions of bank voles and striped field mice (Apodemus agrarius) subjected to ALAN were studied in experimental populations in semi-natural outdoor enclosures. Chapter I explores whether behavioral responses to ALAN of varying intensity are related to animal personality. Results showed that bank voles reduced movement and foraging already under dim light and that bold animals generally moved and foraged more than shy animals. Exclusively under bright illumination did bold animals exploit the food patches more than shy animals. The results demonstrate that bank voles are affected by light intensities prevalent in urban habitats. Additionally, certain light scenarios might lead to an advantage of and a shift towards certain personality types. Chapter II focusses on the effects of partial ALAN on foraging behavior of animals with varying animal personalities while extending the view towards possible carry-over effects of ALAN into the daytime. While bank voles reduced foraging behavior in illuminated areas at night, they increased foraging behavior in those areas at the subsequent day. Bold individuals generally had lower giving-up densities than shy individuals but this difference was especially pronounced during daytime at formerly illuminated food patches. Thus, ALAN can have carry-over effects into the daytime in polyphasic animals and thus has the potential to affect daytime intra- and interspecific interactions. Chapter III broadens the view from the individual to the population level. Experimental populations consisting of bank voles and striped field mice were established in large outdoor enclosures successively experienced natural and artificial light conditions at night. VHF telemetry data revealed that animals were predominantly active during the day under natural conditions. This difference between day and night vanished under ALAN. Additionally, conspecifics reduced home range overlap, proximity and activity synchrony while boldness was not associated with behavioral changed due to ALAN. The results suggest that ALAN has the potential to alter intraspecific interactions and thus can have fitness consequences on the population level. Overall, the present thesis shows that ALAN can affect nighttime and daytime behavior as well as intraspecific interactions of polyphasic small mammals. Differences in risk- taking behavior of individuals may vary in importance depending on other environmental variables. Thus, this thesis hopefully triggers broadening the view regarding the role of an animal's personality in coping with ALAN and the effects on daytime behavior and diurnal species.}, language = {en} } @phdthesis{Parry2023, author = {Parry, Victor}, title = {From individual to community level: Assessing swimming movement, dispersal and fitness of zooplankton}, doi = {10.25932/publishup-59769}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-597697}, school = {Universit{\"a}t Potsdam}, pages = {ix, 118}, year = {2023}, abstract = {Movement is a mechanism that shapes biodiversity patterns across spatialtemporal scales. Thereby, the movement process affects species interactions, population dynamics and community composition. In this thesis, I disentangled the effects of movement on the biodiversity of zooplankton ranging from the individual to the community level. On the individual movement level, I used video-based analysis to explore the implication of movement behavior on preypredator interactions. My results showed that swimming behavior was of great importance as it determined their survival in the face of predation. The findings also additionally highlighted the relevance of the defense status/morphology of prey, as it not only affected the prey-predator relationship by the defense itself but also by plastic movement behavior. On the community movement level, I used a field mesocosm experiment to explore the role of dispersal (time i.e., from the egg bank into the water body and space i.e., between water bodies) in shaping zooplankton metacommunities. My results revealed that priority effects and taxon-specific dispersal limitation influenced community composition. Additionally, different modes of dispersal also generated distinct community structures. The egg bank and biotic vectors (i.e. mobile links) played significant roles in the colonization of newly available habitat patches. One crucial aspect that influences zooplankton species after arrival in new habitats is the local environmental conditions. By using common garden experiments, I assessed the performance of zooplankton communities in their home vs away environments in a group of ponds embedded within an agricultural landscape. I identified environmental filtering as a driving factor as zooplankton communities from individual ponds developed differently in their home and away environments. On the individual species level, there was no consistent indication of local adaptation. For some species, I found a higher abundance/fitness in their home environment, but for others, the opposite was the case, and some cases were indifferent. Overall, the thesis highlights the links between movement and biodiversity patterns, ranging from the individual active movement to the community level.}, language = {en} }