Time filter

Source Type

Kite R.,University of Victoria | Nelson T.,University of Victoria | Stenhouse G.,Foothills Research Institute Grizzly Bear Program | Darimont C.,University of Victoria
Biological Conservation

Advances in GPS telemetry and remote sensing technologies provide researchers with abundant data that can be used to investigate detailed questions about wildlife behavior. Existing methods for linking wildlife movement to remotely sensed landscape data generally rely on the application of subjectively derived distance thresholds to represent proximity (i.e., near or far) relative to disturbance, thereby possibly limiting the scope of research questions and insight gained. We develop an alternative method based on semivariogram modeling that quantifies consistency in movement parameters as a function of distance to disturbance features. Our approach uses movement data to identify spatially explicit scales of wildlife response to linear features. We illustrate the benefit of movement-driven approaches for generating hypotheses about wildlife movement with grizzly bear (Ursus arctos) movement data. We concentrate specifically on building hypotheses to explain how seasonal mortality is linked to near road movements. The movement-driven method demonstrated consistency in step length (i.e., spatial scales of response) ranging from 35. m-90. m from roads, depending on age, sex, and season. Given this pattern, our data suggest a minimum vegetation buffer of 90. m to serve as screening cover along roadsides to improve survival in this ecosystem. More broadly, our generalizable method can identify definitive spatial scales of response around human disturbance features in any wildlife system, thereby providing managers with movement-driven insight to reduce impacts on wildlife in multi-use landscapes. © 2015 Elsevier B.V. Source

Smulders M.,University of Victoria | Nelson T.A.,University of Victoria | Jelinski D.E.,University of Victoria | Nielsen S.E.,University of Alberta | And 2 more authors.
Applied Geography

Geographical spatial analysis approaches are ideally applied to studies of wildlife habitat use when spatial data, such as telemetry data or spatial ranges, are available. For instance, it is often desirable to quantify spatial-temporal patterns of home ranges, which are typically delineated as polygons and represent areas of habitat that support wildlife functions. Changes to home ranges over time are often presented as variation in mean polygon area. This two-dimensional approach ignores potentially important spatial-temporal characteristics of habitat use, including site fidelity, range contraction, and expansion. Using Spatial-Temporal Analysis of Moving Polygons (STAMP) we examined a set of movement data for a subpopulation of adult female grizzly bears (Ursus arctos) for the period from 1999 to 2003 in the Rocky Mountain foothills region of Alberta, Canada. Home range change was quantified over two-year periods and evaluated on the basis of variable offspring dependency (i.e., whether the females had no cubs, cubs-of-the-year (COY), or yearling cubs) and foraging season. Solitary bears showed the greatest amount of home range fidelity, with an increase in range size during the mating season. Female grizzly bears with offspring experienced substantial home range change. Sows with COY had a reduced maternal home range size, especially during mating season, while those with yearling offspring had an increased home range size. The patterns of home range change were consistent with those expected if some combination of mobility and infanticide were the driving ecological mechanisms. We conclude that offspring dependency does not impact the degree of site fidelity but does impact the nature of home range change experienced. We also suggest that the spatial-temporal change in female grizzly home ranges could be used to infer breeding status and as a population monitoring tool. A geographical approach to home range change provides a simple and quantitative approach to mapping spatial-temporal patterns of habitat use and animal movement. © 2012 Elsevier Ltd. Source

Graham K.,Foothills Research Institute Grizzly Bear Program | Stenhouse G.B.,Foothills Research Institute Grizzly Bear Program
Canadian Field-Naturalist

An understanding of the natural history of the Grizzly Bear (Ursus arctos) is important for recovery planning. We present data on home range size, movements and denning chronology collected using Global Positioning System (GPS) collars on Grizzly Bears in west-central Alberta. Mean annual kernel estimates for adult (1034 ± 656 (SD) km2) and subadult (1298 ± 1207 km2) males were larger than those for females with cubs of the year (213 ± 212 km2) and lone adult females (337 ± 176 km2) but not different from sub-adult females, females with yearlings, or females with ≥ 2-yr old cubs (P > 0.05). Mean rates of movement among female age-reproductive classes were different from each other (Z9 < 2.70, P > 0.05) but not different from sub-adult males (Z9 < 2.70, P > 0.05). Rates of movement of adult males were significantly different only from those of females with cubs of the year (Z9 = 3.94, P = 0.001). The greatest amount of movement occurred in June and the least in october. Bears traveled fastest in the morning and evening and slowest at night. Pregnant females had the longest denning period (175 days, ± 16 days SD). No difference was detected in denning duration among the remaining five age-sex-reproductive classes (P > 0.05). GPS collars provided large location datasets from which accurate home range estimates, hourly movement rates, and precise denning dates were determined. Examining similarities and differences in the basic biology of Grizzly Bears from various locations will improve our understanding of the plasticity of this species and the potential impacts of habitat and climate change. © 2014, Canadian Field-Naturalists' Club. All rights reserved. Source

Discover hidden collaborations