Resources
​Photo credit: Dave Showalter

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Recent studies
This page will be updated occasionally and will summarize recent studies that have implications for rangeland wildlife ecology and management. 

September 4, 2020
Does Reproductive Status Influence Habitat Selection by Female Greater Sage-grouse in a Sagebrush-Juniper Landscape?
​Rabon, J.C.*, P.S. Coates, M.A. Ricca, and T.N. Johnson.​

Greater sage-grouse (Centrocercus urophasianus, hereafter, sage-grouse) in the Great Basin have experienced loss of habitat due to expansion of conifer woodlands into sagebrush steppe.  Conifer expansion can alter the understory by reducing cover and species richness of herbaceous plants and shrubs, or may affect the community of predators that prey on grouse, either of which can influence the availability of resources required by sage-grouse for brood-rearing and survival.  Sage-grouse generally avoid high levels of conifer cover (> 10%) but can vary in their response to low levels of conifer cover (> 0–10%).  Selection patterns by hens may be affected by differences in resource needs or predation risk between brooding (i.e., hens with chicks) and non-brooding hens (i.e., hens without chicks).  We investigated whether reproductive status influenced habitat selection at multiple spatial scales among hens in a landscape undergoing conifer expansion.  We predicted that at broad spatial scales brooding hens would be less likely to select areas with conifer than non-brooding hens and at a fine spatial scale would more likely select habitats with greater concealment cover to decrease predation risk of chicks.  We conducted our study during the 2017–18 breeding seasons in southwestern Idaho, where the expansion of western juniper (Juniperus occidentalis, hereafter, juniper) is a primary threat to local sage-grouse populations.  We employed a use and available design and collected data on habitat at broad spatial extents (hereafter, macro-scales) using remotely-sensed layers and at a fine spatial extent (hereafter, micro-scale) with field-based surveys.  We collected data at macro-scales from 2,059 use and available locations for 11 brooding and 19 non-brooding hens, and at the micro-scale from 181 use and available locations from 11 brooding and 15 non-brooding hens.  At macro-scales, both reproductive groups generally avoided habitats with cover class II (> 10–20% juniper cover) and III (> 20% juniper cover) but non-brooding hens selected for cover class I (> 0–10% juniper cover) throughout the brood-rearing season whereas brooding hens avoided cover class I during the latter half of the brood-rearing season.  Additionally, non-brooding hens had a stronger preference for woody-dominated wetlands while brooding hens preferred herbaceous wetlands.  At the micro-scale, brooding hens were more likely than non-brooding hens to select habitats with taller perennial grass and non-sagebrush shrubs.  Although non-brooding hens preferred cover class I, previous studies have demonstrated lower survival of sage-grouse that occupy these areas, and removal of cover class I is predicted to benefit sage-grouse populations, especially if it results in improved hen survival.  Removal of juniper around wetlands dominated by woody and herbaceous vegetation, and mesic habitats with taller non-sagebrush shrubs may be the most beneficial because increasing the availability of these habitats could positively influence survival of chicks and adults.

Useful Links

Sage Grouse Initiative
Partnership of ranchers, agencies, universities, non-profit groups, and businesses that embrace a common vision: wildlife conservation through sustainable ranching.

The Rangeland Center
Collaborative unit at the University of Idaho that includes researchers, educators, students, and land managers.

Life on the Range
Educational project from the Idaho Rangeland Resources Commission showcasing multiple-use management.

U.S. Fish & Wildlife Service
Up-to-date greater sage-grouse information.