Movement ecology of fishers (Pekania pennanti) within a semi-urban landscape

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LAPOINT, Scott Daniel, 2013. Movement ecology of fishers (Pekania pennanti) within a semi-urban landscape

@phdthesis{LaPoint2013Movem-24838, title={Movement ecology of fishers (Pekania pennanti) within a semi-urban landscape}, year={2013}, author={LaPoint, Scott Daniel}, address={Konstanz}, school={Universität Konstanz} }

2013-10-16T10:01:23Z eng Bewegungsökologie der Fischmarder (Pekania pennanti) innerhalb einer semi-urbanen Landschaft deposit-license Movement ecology of fishers (Pekania pennanti) within a semi-urban landscape 2013 2013-10-16T10:01:23Z LaPoint, Scott Daniel Habitat fragmentation and urbanization are ubiquitous threats to mammals, forcing species to either become locally extinct or to adapt. The challenge for species to adapt however is great, partly because of the wide disparity between the quickness of these anthropogenic forces and the rate at which species can adapt through evolutionary processes. Yet some species are adapting to fragmented, potentially novel, urban landscapes. Until now however, our ability to investigate species responses to these threats remained practically infeasible, due to the technological limitations of monitoring free-ranging animals. However, the field of movement ecology is spurring interest in these questions, driving rapid technological improvements in biotelemetry methods, offering biologists unprecedented opportunities. I capitalized on these opportunities during my dissertation work and investigated a species whose responses to habitat fragmentation apparently varies greatly across its geographic range, hoping to explore hypotheses concerning the ecological and behavioral responses of a carnivore to these anthropogenic forces. This dissertation is an attempt to better understand the behavior and ecology of fishers (Pekania pennanti) that have recently colonized the previously considered inhospitable, semi-urban landscape surrounding Albany, New York, USA. Within this dissertation, I compare the species historic, most-contracted, and current geographic range, and show that fishers have re-colonized much of their historical eastern range, (including suburban landscapes within the Northeastern United States), yet remain in isolated fragments within their historic western range (Chapter 2). Understanding how this species can successfully colonize a suburban landscape, but remain threatened elsewhere, motivated the field-based portion of this dissertation.<br /><br />I hypothesized that fishers in my study area have adapted their behaviors (e.g., the timing of their activity and their movement-habitat patterns) in response to human activities. To test these hypotheses, I captured and fitted 33 free-ranging fishers across a habitat fragmentation continuum during three winter field seasons. I deployed state-of-the-art GPS-tracking collars, equipped with tri-axial accelerometers and remote downloading capabilities and managed these recorded data via movebank.org. It was necessary to develop a novel system for collecting the temporal and spatial high-resolution data that would be required to test this hypothesis. Our accelerometer-informed GPS-fix attempt schedule (described in Chapter 3) achieved great success in both extending the deployment duration of our GPS-tracking collars while simultaneously recording more locations, ultimately yielding more realistic fisher movement tracks.<br /><br />It appears that these fishers are facilitating their survival within this semi-urban landscape through adjustments in the timing of their activity and their movement patterns. Our accelerometers yielded activity data (i.e., overall dynamic body acceleration) that suggests that these fishers are nocturnal and are avoiding automobile traffic volume peaks by ceasing their activity earlier when these peaks occur earlier in the morning. Fishers also appear less selective in their habitat requirements here than reported in the literature, utilizing all forest cover types available to them rather than particular forest characteristics. However, my study animals rarely utilized only one forest patch, due to their small area, and instead crossed roads and other features nightly to move between multiple forest patches. From my model of fisher behavior, it appears that fishers are utilizing movement corridors to move between these patches. Unfortunately however, two popular approaches for identifying potential corridors (i.e., least-cost path analysis and circuit theory) poorly predicted the location of these corridors. Further, an independent set of animal movement data, derived from camera trap detections, validated my model predictions and confirmed that the other two models performed relatively poorly.<br /><br />In summary, the work presented within this dissertation tells an encouraging story of persistence and resourcefulness, offering hope for the conservation of imperiled wildlife. The fisher has been thought to be highly, negatively impacted by human activities and landscape disturbance, yet their recent colonization of suburban areas suggests the contrary. I am confident that the results of future efforts similar to those outlined here will be vital to conservation efforts. Given the rate and ubiquity of threats to wildlife, we must improve our understanding of how some species are coping with these threats so that we can identify the traits that allow them to do so. LaPoint, Scott Daniel

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

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