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UBC Theses and Dissertations

Habitat selection of Dusky Grouse on a biosolids-remediated cattle ranch in British Columbia Lawson, Kirstie Jaylene


In North America, habitat loss and fragmentation have caused declines in many gallinaceous species. Before we can understand how these changes to a landscape affect an individual species, we must first understand how that species uses their habitat. Our understanding of dusky grouse (Dendragapus obscurus) habitat selection is lacking and I focus my research on increasing our knowledge of this forest grouse species. In this thesis, I assess microhabitat selection at nesting and brood-rearing sites, as well as patch-level habitat selection and the effects of biosolids on amendments on habitat selection of dusky grouse. I trapped and radio-collared 26 dusky grouse hens during 2016-2017 and tracked individuals throughout the summer months (May-July). I used model selection in an AIC framework to determine which vegetation variables affect dusky grouse choice of nesting and brood-rearing sites at the microhabitat level. Dusky grouse are habitat generalists. However, hens selected nest sites with high visual cover, and nest success was positively influenced by visual obstruction of the nest bowl. This suggests that cover from predators is important when hens select nest sites, and that predation may be influenced by the predator’s ability to see the nest. Brood sites were more variable, and brood hens appeared to choose sites based on non-vegetative variables. Furthermore, the use of biosolids, treated human waste, on the landscape allowed me to look at dusky grouse use these amendments. I assess broad-scale habitat select through patch-level use of available habitat types and the distance dusky grouse traveled into biosolids-amended and untreated grasslands. I found drastic year differences in selection and use of grasslands, and weather or food abundance may play a role in site selection. In 2017, a much drier, warmer year, dusky grouse hens traveled significantly further into biosolids-amended grasslands than untreated grasslands. In 2016, hens traveled much further into grasslands overall, showing similar distributions in both biosolids-amended and untreated grasslands. My research suggests that biosolids may be beneficial for dusky grouse in drought years, by enhancing plant growth and increasing insect densities.

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