Date of Award

5-17-2023

Document Type

Thesis

Abstract

An animal's temporal niche, or when it is active during the 24-hour day, is a fundamental aspect of its overall niche and ecology. Animals are confined to a temporal niche to maximize energetic gains while avoiding agonistic encounters with predators or intraguild competitors. An animal's temporal niche can be influenced by a variety of biotic and abiotic factors, and the temporal niche of predators is often established through a careful balance of prey behavior and the predator's physiological adaptations. This study examined the seasonal change of patterns of activity in Canada lynx (Lynx canadensis) in Northern Alaska using both GPS transmitters and triaxial accelerometers. The distance between consecutive GPS locations, or step length, is a common metric used to assess how movement rates vary across space and time and is often used to examine activity patterns of free ranging terrestrial animals. However, activity can only be examined at a high resolution for a short period of time, as fix rate inversely affects battery life of the GPS transmitter. Further, animal activity includes a range of behaviors that are not always discernable by spatial displacement alone (e.g., grooming, eating, some hunting behaviors), thus GPS transmitters can sometimes lead to underestimation of activity. Triaxial accelerometers can be used in addition to GPS transmitters to record activity in the presence or absence of spatial displacement, therefore theoretically providing a more accurate index of activity of free ranging animals. Both GPS and accelerometers separately indicated that lynx were most active near twilight and maintained a bimodal crepuscular-like activity pattern in spring and fall, but they switched to a unimodal pattern of activity during mid-day in winter. Hourly GPS data alone was insufficient in detecting diel activity patterns in 6 of 12 instances. We also found that step length and vectorial dynamic body acceleration (VeDBA), an index of body acceleration, were correlated in a positive curvilinear fashion in all individuals. However, there were times when step length was disproportionately lower than acceleration. These intervals of high activity, but short spatial displacements, could be indicative of hunting in a patch of habitat. Consistent with this interpretation, animals that exhibited this dichotomy had an increased likelihood of rest in the next hour. We also found that mean VeDBA and mean step length were not correlated at a seasonal scale, and mean step length and other GPS derived metrics were much more variable between individuals than VeDBA. We conclude that there are multiple ways accelerometers can provide additional information that can supplement GPS location data to provide a more complete picture of animal activity and behavior, including using the relationship of acceleration and spatial displacement data to shed light on space use patterns that may not be apparent using GPS data alone.

Handle

http://hdl.handle.net/11122/13241

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