| Greater sage-grouse (Centrocercus urophasianus) currently occupy half of their historic range and populations range-wide have declined by 15-90%. The endangered Alberta population has declined by as much as 92%, likely a result of reduced recruitment due to low nest success and poor chick survival. I use spatial modelling techniques to understand various habitat, climatic, and anthropogenic factors that drive nest and brood habitat selection, and concurrently assess factors that make habitats 'risky' for nests and chicks. At local scales, females recognised ecological cues related to nest success, selecting for large dense patches of sagebrush with thick grass cover, placing their nests under moderate density shrubs with suitable obstruction cover from tall grass. Enhanced nest success resulting from forb cover at all scales, and additional shrub species at larger scales, however, are ecological cues that are missed, potentially creating ecological traps. Broods used habitats that were rich in forbs and had moderate sagebrush cover, tall grass, but less grass cover. Although selection for sagebrush enhanced chick survival, avoidance of grass dominated areas increased risk. Sage-grouse may be making tradeoffs between secure-dense cover habitats, and rare forb-rich foraging habitats that are more open and inherently more risky, particularly in dry years. Landscape-scale models showed selection for heterogeneous patches of high sagebrush cover and strong avoidance of anthropogenic edge habitat for nest sites. Similar heterogeneous high productivity habitats with sagebrush are selected by broods while avoiding human developments, cropland, and high densities of oil well sites. Chick failure tended to occur in proximity to oil and gas developments and along riparian habitats. I predicted these models spatially, identifying source habitats where nests or chicks were likely to occur and survive, and 'attractive' sink habitats where occurrence is high, but nests fail and chicks die. Ten percent and 5% of the study area was source habitat, whereas 19% and 15% of habitat was sink habitat for nest and broods, respectively. My habitat models identified areas that need protection, and habitats that need immediate management to enhance recruitment and sustain the viability of this population. I make management recommendations following a collaborative adaptive management approach. |
