Selection and Survival of Greater Sage-Grouse Broods in Mesic Areas of Long Valley, California (2003 - 2018)

We evaluated brood-rearing habitat selection and brood survival of greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) in Long Valley, California, an area where the water rights are primarily owned by the city of Los Angeles and water is used locally to irrigate for livestock. This area thus represents a unique balance between the needs of wildlife and people that could increasingly define future water management. In this study, sage-grouse broods moved closer to the edge of mesic areas and used more interior areas during the late brood-rearing period, selecting for greener areas after 1 July. Mesic areas were particularly important during dry years, with broods using areas farther interior than in wet years. Brood survival was also positively influenced by the availability and condition of mesic resources, as indicated by variation in values of normalized difference vegetation index (NDVI), with survival peaking at moderate values of NDVI and just outside the edge but decreasing inside the mesic areas. Our results highlight the importance of quality edge habitat of large mesic areas for sage-grouse to balance habitat selection and survival, particularly during drier years and during the late brood-rearing period, which is a critical period because chick survival has been shown to influence population growth. This study also highlights the implications of large-scale anthropogenic water manipulation, and the balance between local irrigation and water distribution to benefit other regions, from the context of a species of high conservation concern in North American sagebrush ecosystems.

These data support the following publication:
Severson, J.P., Coates, P.S., Milligan, M.C., O'Neil, S.T., Ricca, M.A., Abele, S.C., Boone, J.D., and Casazza, M.L., In-review. Moisture abundance and proximity mediates seasonal use of mesic habitat and survival of greater sage-grouse broods. Ecological Solutions and Evidence.