Greater Sage-Grouse Habitat Dynamics and Grazing, A Study of Vegetation Indices and Survival

North American rangelands are vast, open landscapes that support diverse ecosystems and provide many ecosystem services. Many wildlife call sagebrush rangelands home, including the Greater sage-grouse (sage-grouse; Centrocercus urophasianus). Sage-grouse habitat encompasses 165 million acres across western North America, and this bird has been of conservation concern as their populations drastically declined since the 1960s. Rangelands are also grazed by livestock, which has the potential to negatively affect sagebrush ecosystems when overgrazed or overstocked, which could be detrimental to sage-grouse nesting habitat. Additionally, sagebrush rangelands undergo annual variations in precipitation, temperature, growing season length, and vegetation vigor, which has been compounded by climate change. My theses explores the link between landscape characteristics, vegetation dynamics, and sage-grouse vital rates in sagebrush rangelands in Northeastern Utah. I analyzed the effect of climate, vegetation phenology, and landscape characteristics across 10 years of sage-grouse nest fate data. The results revealed that sage-grouse nest success was higher in nests that had more days between nest initiation and the peak of the annual growth season. These results suggest that climatic factors influencing vegetation growth may be substantial for sage-grouse nest survival. I also evaluated the connection between remotely sensed Normalized Difference Vegetation Index and its relationship to livestock use. Results of this study indicate there was no relationship between Normalized Difference Vegetation Index (at a 150m scale) and grazing patterns, however, my results showed a positive correlation between Normalized Difference Vegetation Index and herbaceous and woody vegetation abundance within the transects. This suggests that while Normalized Difference Vegetation Index may not directly correlate with livestock patterns, it remains a valuable tool for monitoring herbaceous vegetation growth and cover.