@phdthesis{Stiegler2023,
  author    = {Stiegler, Jonas},
  title     = {Mobile link functions in unpredictable agricultural landscapes},
  doi       = {10.25932/publishup-62202},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-622023},
  school      = {Universit{\"a}t Potsdam},
  pages     = {155},
  year      = {2023},
  abstract  = {Animal movement is a crucial aspect of life, influencing ecological and evolutionary processes. It plays an important role in shaping biodiversity patterns, connecting habitats and ecosystems. Anthropogenic landscape changes, such as in agricultural environments, can impede the movement of animals by affecting their ability to locate resources during recurring movements within home ranges and, on a larger scale, disrupt migration or dispersal. Inevitably, these changes in movement behavior have far-reaching consequences on the mobile link functions provided by species inhabiting such extensively altered matrix areas. In this thesis, I investigate the movement characteristics and activity patterns of the European hare (Lepus europaeus), aiming to understand their significance as a pivotal species in fragmented agricultural landscapes. I reveal intriguing results that shed light on the importance of hares for seed dispersal, the influence of personality traits on behavior and space use, the sensitivity of hares to extreme weather conditions, and the impacts of GPS collaring on mammals' activity patterns and movement behavior. In Chapter I, I conducted a controlled feeding experiment to investigate the potential impact of hares on seed dispersal. By additionally utilizing GPS data of hares in two contrasting landscapes, I demonstrated that hares play a vital role, acting as effective mobile linkers for many plant species in small and isolated habitat patches. The analysis of seed intake and germination success revealed that distinct seed traits, such as density, surface area, and shape, profoundly affect hares' ability to disperse seeds through endozoochory. These findings highlight the interplay between hares and plant communities and thus provide valuable insights into seed dispersal mechanisms in fragmented landscapes. By employing standardized behavioral tests in Chapter II, I revealed consistent behavioral responses among captive hares while simultaneously examining the intricate connection between personality traits and spatial patterns within wild hare populations. This analysis provides insights into the ecological interactions and dynamics within hare populations in agricultural habitats. Examining the concept of animal personality, I established a link between personality traits and hare behavior. I showed that boldness, measured through standardized tests, influences individual exploration styles, with shy and bold hares exhibiting distinct space use patterns. In addition to providing valuable insights into the role of animal personality in heterogeneous environments, my research introduced a novel approach demonstrating the feasibility of remotely assessing personality types using animal-borne sensors without additional disturbance of the focal individual. While climate conditions severely impact the activity and, consequently, the fitness of wildlife species across the globe, in Chapter III, I uncovered the sensitivity of hares to temperature, humidity, and wind speed during their peak reproduction period. I found a strong response in activity to high temperatures above 25°C, with a particularly pronounced effect during temperature extremes of over 35°C. The non-linear relationship between temperature and activity was characterized by contrasting responses observed for day and night. These findings emphasize the vulnerability of hares to climate change and the potential consequences for their fitness and population dynamics with the ongoing rise of temperature. Since such insights can only be obtained through capturing and tagging free-ranging animals, I assessed potential impacts and the recovery process post-collar attachment in Chapter IV. For this purpose, I examined the daily distances moved and the temporal-associated activity of 1451 terrestrial mammals out of 42 species during their initial tracking period. The disturbance intensity and the speed of recovery varied across species, with herbivores, females, and individuals captured and collared in relatively secluded study areas experiencing more pronounced disturbances due to limited anthropogenic influences. Mobile linkers are essential for maintaining biodiversity as they influence the dynamics and resilience of ecosystems. Furthermore, their ability to move through fragmented landscapes makes them a key component for restoring disturbed sites. Individual movement decisions determine the scale of mobile links, and understanding variations in space use among individuals is crucial for interpreting their functions. Climate change poses further challenges, with wildlife species expected to adjust their behavior, especially in response to high-temperature extremes, and comprehending the anthropogenic influence on animal movements will remain paramount to effective land use planning and the development of successful conservation strategies. This thesis provides a comprehensive ecological understanding of hares in agricultural landscapes. My research findings underscore the importance of hares as mobile linkers, the influence of personality traits on behavior and spatial patterns, the vulnerability of hares to extreme weather conditions, and the immediate consequences of collar attachment on mammalian movements. Thus, I contribute valuable insights to wildlife conservation and management efforts, aiding in developing strategies to mitigate the impact of environmental changes on hare populations. Moreover, these findings enable the development of methodologies aimed at minimizing the impacts of collaring while also identifying potential biases in the data, thereby benefiting both animal welfare and the scientific integrity of localization studies.},
  language  = {en}
}
@phdthesis{Jaiser2013,
  author    = {Jaiser, Ralf},
  title     = {Dreidimensionale Diagnostik der großskaligen Zirkulation der Tropo- und Stratosph{\"a}re},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-69064},
  school      = {Universit{\"a}t Potsdam},
  year      = {2013},
  abstract  = {In dieser Arbeit werden Konzepte f{\"u}r die Diagnostik der großskaligen Zirkulation in der Troposph{\"a}re und Stratosph{\"a}re entwickelt. Der Fokus liegt dabei auf dem Energiehaushalt, auf der Wellenausbreitung und auf der Interaktion der atmosph{\"a}rischen Wellen mit dem Grundstrom. Die Konzepte werden hergeleitet, wobei eine neue Form des lokalen Eliassen-Palm-Flusses unter Einbeziehung der Feuchte eingef{\"u}hrt wird. Angewendet wird die Diagnostik dann auf den Reanalysedatensatz ERA-Interim und einen durch beobachtete Meerestemperatur- und Eisdaten angetriebenen Lauf des ECHAM6 Atmosph{\"a}renmodells. Die diagnostischen Werkzeuge zur Analyse der großskaligen Zirkulation sind einerseits n{\"u}tzlich, um das Verst{\"a}ndnis der Dynamik des Klimasystems weiter zu f{\"o}rdern. Andererseits kann das gewonnene Verst{\"a}ndnis des Zusammenhangs von Energiequellen und -senken sowie deren Verkn{\"u}pfung mit synoptischen und planetaren Wellensystemen und dem resultierenden Antrieb des Grundstroms auch verwendet werden, um Klimamodelle auf die korrekte Wiedergabe dieser Beobachtungen zu pr{\"u}fen. Hier zeigt sich, dass die Abweichungen im untersuchten ECHAM6-Modelllauf bez{\"u}glich des Energiehaushalts klein sind, jedoch teils starke Abweichungen bez{\"u}glich der Ausbreitung von atmosph{\"a}rischen Wellen existieren. Planetare Wellen zeigen allgemein zu große Intensit{\"a}ten in den Eliassen-Palm-Fl{\"u}ssen, w{\"a}hrend innerhalb der Strahlstr{\"o}me der oberen Troposph{\"a}re der Antrieb des Grundstroms durch synoptische Wellen verf{\"a}lscht ist, da deren vertikale Ausbreitung gegen{\"u}ber den Beobachtungen verschoben ist. Untersucht wird auch der Einfluss von arktischen Meereis{\"a}nderungen ausgehend vom Bedeckungsminimum im August/September bis in den Winter. Es werden starke positive Temperaturanomalien festgestellt, welche an der Oberfl{\"a}che am gr{\"o}ßten sind. Diese f{\"u}hren vor allem im Herbst zur Intensivierung von synoptischen Systemen in den arktischen Breiten, da die Stabilit{\"a}t der troposph{\"a}rischen Schichtung verringert ist. Im darauffolgenden Winter stellen sich barotrope bis in die Stratosph{\"a}re reichende {\"A}nderungen der großskaligen Zirkulation ein, welche auf Meereis{\"a}nderungen zur{\"u}ckzuf{\"u}hren sind. Der meridionale Druckgradient sinkt und f{\"u}hrt so zu einem Muster {\"a}hnlich einer negativen Phase der arktischen Oszillation in der Troposph{\"a}re und einem geschw{\"a}chten Polarwirbel in der Stratosph{\"a}re. Diese Zusammenh{\"a}nge werden ebenfalls in einem ECHAM6-Modelllauf untersucht, wobei vor allem der Erw{\"a}rmungstrend in der Arktis zu gering ist. Die großskaligen Ver{\"a}nderungen im Winter k{\"o}nnen zum Teil auch im Modelllauf festgestellt werden, jedoch zeigen sich insbesondere in der Stratosph{\"a}re Abweichungen f{\"u}r die Periode mit der geringsten Eisausdehnung. Die vertikale Ausbreitung planetarer Wellen von der Troposph{\"a}re in die Stratosph{\"a}re ist in ECHAM6 mit sehr großen Abweichungen wiedergegeben. Somit stellt die Wellenausbreitung insgesamt den gr{\"o}ßten in dieser Arbeit festgestellten Mangel in ECHAM6 dar.},
  language  = {de}
}