Microhabitat Conditions in Wyoming's Sage-Grouse Core Areas: Effects on Nest Site Selection and Success

PLoS One. 2016 Mar 22;11(3):e0150798. doi: 10.1371/journal.pone.0150798. eCollection 2016.

Abstract

The purpose of our study was to identify microhabitat characteristics of greater sage-grouse (Centrocercus urophasianus) nest site selection and survival to determine the quality of sage-grouse habitat in 5 regions of central and southwest Wyoming associated with Wyoming's Core Area Policy. Wyoming's Core Area Policy was enacted in 2008 to reduce human disturbance near the greatest densities of sage-grouse. Our analyses aimed to assess sage-grouse nest selection and success at multiple micro-spatial scales. We obtained microhabitat data from 928 sage-grouse nest locations and 819 random microhabitat locations from 2008-2014. Nest success was estimated from 924 nests with survival data. Sage-grouse selected nests with greater sagebrush cover and height, visual obstruction, and number of small gaps between shrubs (gap size ≥0.5 m and <1.0 m), while selecting for less bare ground and rock. With the exception of more small gaps between shrubs, we did not find any differences in availability of these microhabitat characteristics between locations within and outside of Core Areas. In addition, we found little supporting evidence that sage-grouse were selecting different nest sites in Core Areas relative to areas outside of Core. The Kaplan-Meier nest success estimate for a 27-day incubation period was 42.0% (95% CI: 38.4-45.9%). Risk of nest failure was negatively associated with greater rock and more medium-sized gaps between shrubs (gap size ≥2.0 m and <3.0 m). Within our study areas, Wyoming's Core Areas did not have differing microhabitat quality compared to outside of Core Areas. The close proximity of our locations within and outside of Core Areas likely explained our lack of finding differences in microhabitat quality among locations within these landscapes. However, the Core Area Policy is most likely to conserve high quality habitat at larger spatial scales, which over decades may have cascading effects on microhabitat quality available between areas within and outside of Core Areas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Artemisia / physiology
  • Conservation of Natural Resources / methods
  • Ecosystem
  • Female
  • Galliformes / physiology*
  • Nesting Behavior / physiology*
  • Population Dynamics
  • Wyoming

Grant support

Research funding was provided by: American Colloid Company; Anadarko Petroleum Corporation; Bates Hole, Bighorn Basin, South-Central, Southwest, and Wind River/Sweetwater River Local Sage-Grouse Working Groups; Jack H. Berryman Institute; Lincoln County Predator Management Board; Margaret and Sam Kelly Ornithological Research Fund; Predatory Animal District of Sweetwater County; School of Energy Resources and Wyoming Reclamation and Restoration Center at the University of Wyoming; Uinta County Predator Management Board; Utah Agricultural Experiment Station; Wyoming Animal Damage Management Board; Wyoming Sage-grouse Conservation Fund of the Wyoming Game and Fish Department; Wyoming Wildlife and Natural Resource Trust. Funding for analysis and publication of this paper was provided by the State of Wyoming Legislature through the Wyoming Wildlife and Natural Resource Trust on behalf of the Wyoming Sage-Grouse Implementation Team. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.