Abstract
Few studies have examined differential responses of partially migratory ungulates to human development or activity, where some individuals in a population migrate and others do not. Yet understanding how animals with different movement tactics respond to anthropogenic disturbance is key to sustaining global ungulate migrations. We examined seasonal resource selection of a partially migratory population of pronghorn (Antilocapra americana) in the Northern Sagebrush Steppe of Alberta, Saskatchewan, and Montana from 2003 to 2011. We developed step-selection functions (SSF) for migrant and resident pronghorn during the summer and winter at two spatial scales (second order and third order) and then integrated SSFs across scales to estimate pronghorn responses to fences and subsequent habitat loss from these features while accounting for responses to other resource use. Both migrant and resident pronghorn showed the strongest responses to natural and anthropogenic features at the second order and weaker responses at the third order. Selection responses of migrant and residents differed the most in response to normalized difference vegetation index, topography, and anthropogenic features. Seasonally, selection for intermediate greenness was strongest in summer, whereas avoidance of roads strongly influenced winter resource selection of both tactics. Both migrant and resident pronghorn showed strong avoidance of fencing at both spatial scales during summer and winter. Model predictions with complete removal of fences from the landscape (i.e., natural conditions) predicted an increase in the area of highquality habitat of 16–38%. In contrast, doubling fence density on the landscape decreased the amount of high-quality habitat by 1–11% and increased low-quality habitat by 13–21%. Our results suggest that pronghorn winter and summer ranges can be improved by reducing the density of fences on the landscape, or mitigation measures to enhance fence crossings, to alleviate the indirect loss of habitat for this important endemic prairie species.
| Original language | English |
|---|---|
| Article number | e02791 |
| Journal | Ecosphere |
| Volume | 10 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2019 |
Funding
We thank M. Grue and J. Landry-Deboer (Alberta Conservation Association), D. Eslinger and K. Morton (Alberta Fish and Wildlife), C. Gate, M. Suitor, and D. Bender (University of Calgary) for assistance with the Alberta component of our study. We thank K. Johnson, M. Sullivan, S. Thompson, S. Story, A. Messer, J. Herbert, and J. Gude (Montana Fish, Wildlife and Parks), P. Gunderson, J. Carlson, M. Albers, and R. Adams (Bureau of Land Management), J. Pogorzelec, C. Lees, and E. Beveridge (Saskatchewan Ministry of Environment), K. Kunkel, D. Jorgensen, and S. Forrest (World Wildlife Fund) for assistance with the Montana and Saskatchewan component of our study. A thank you to D. Eacker for assistance with R and C. Brunes for graphic design. We also thank Quicksilver Air Inc., D. Hitch, Bighorn Helicopters, Inc., Pathfinder Helicopter Wildlife Management, and Allison Air Service for excellent capture and surveillance of pronghorn during the study. This study was funded by the Alberta Antelope Guides, Alberta Conservation Association (ACA), Alberta Fish and Game Association (Zone 1), Alberta Professional Outfitters Society, Alberta Sport Recreation Parks and Wildlife Foundation, Canadian Forces Base Suffield, Counter Assault Inc., Foundation for North American Wild Sheep—Eastern Chapter, MITACS Inc.—Accelerate Program, Montana Chapter of The Wildlife Society, Montana Fish, Wildlife & Parks (FWP), National Fish and Wildlife Foundation, Petro-Canada Sustainable Grasslands Applied Research Program, Safari Club International, Safari Club International Alberta Chapter & Northern Alberta Chapter, Sagebrush Science Initiative (a collaboration between the U.S. Fish and Wildlife Services and Western Association of Fish and Wildlife Agencies), Saskatchewan Ministry of Environment, University of Calgary, University of Montana, U.S. Bureau of Land Management (BLM), and World Wildlife Fund (WWF). Additional in-kind support was provided by The Miistakis Institute, FWP, ACA, BLM, and WWF. Lastly, we thank Subject-matter Editor R. Parmenter and two anonymous reviewers for their comments and insights on an earlier draft which greatly improved our paper.
| Funders |
|---|
| Lukuru Wildlife Research Foundation |
| Hornocker Wildlife Institute/Wildlife Conservation Society |
| World Wildlife Fund |
| Bureau of Land Management |
| Alberta Conservation Association |
| Mitacs Canadian Science Policy Fellow |
Keywords
- Antilocapra americana
- Connectivity
- Fences
- Habitat loss
- Movement barriers
- Movement tactic
- Pronghorn
- Resource selection