Nest-site selection and reproductive success of greater sage-grouse in a fire-affected habitat of northwestern Nevada

Abstract

Identifying links between micro‐habitat selection and wildlife reproduction is imperative to population persistence and recovery. This information is particularly important for landscape species such as greater sage‐grouse (Centrocercus urophasianus; sage‐grouse). Although this species has been widely studied, because environmental factors can affect sage‐grouse populations, local and regional studies are crucial for developing viable conservation strategies. We studied the habitat‐use patterns of 71 radio‐marked sage‐grouse inhabiting an area affected by wildfire in the Virginia Mountains of northwestern Nevada during 2009–2011 to determine the effect of micro‐habitat attributes on reproductive success. We measured standard vegetation parameters at nest and random sites using a multi‐scale approach (range = 0.01–15,527 ha). We used an information‐theoretic modeling approach to identify environmental factors influencing nest‐site selection and survival, and determine whether nest survival was a function of resource selection. Sage‐grouse selected micro‐sites with greater shrub canopy cover and less cheatgrass (Bromus tectorum) cover than random sites. Total shrub canopy, including sagebrush (Artemisia spp.) and other shrub species, at small spatial scales (0.8 ha and 3.1 ha) was the single contributing selection factor to higher nest survival. These results indicate that reducing the risk of wildfire to maintain important sagebrush habitats could be emphasized in sage‐grouse conservation strategies in Nevada. Managers may seek to mitigate the influx of annual grass invasion by preserving large intact sagebrush‐dominated stands with a mixture of other shrub species. For this area of Nevada, the results suggest that ≥40% total shrub canopy cover in sage‐grouse nesting areas could yield improved reproductive success. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Are Sage‐Grouse Fine‐Scale Specialists or Shrub‐Steppe Generalists?

“…Studies employing multiple regression model‐based methods less susceptible to confounding variables provide equivocal support for selection of greater herbaceous vegetation height or cover. Positive selection is supported in several of these studies (Aldridge 2005, Holloran et al 2005, Tack 2009, Gibson et al 2016) but unsupported in many others (Aldridge and Brigham 2002, Kolada et al 2009, Doherty et al 2010, Lockyer et al 2015, Dinkins et al 2016).…”

Greater sage‐grouse vital rates after wildfire

“…Although we did not document direct effects of post‐fire land cover on nest survival, we observed potential indirect effects of habitat and land cover through the interaction between year (i.e., a coarse reflection of time since fire) and nesting attempt (i.e., a coarse reflection of nest initiation date in relation to growing season progression). Sage‐grouse select nest sites based on micro‐scale vegetation (Connelly et al ); thus, micro‐site habitat characteristics may have a greater influence on survival than landscape‐scale habitat configuration (Baxter et al , Webb et al , Lockyer et al ). In addition to this potential dynamic, the sampled nests in our study may not have had enough variation in landscape‐level habitat covariates to detect an effect on nest survival.…”

“…Most studies of the effects of fire on sage‐grouse populations and habitat have occurred following prescribed fires or multiple years after small wildfires (Lockyer et al ). Additionally, studies on the effects of fire on sage‐grouse habitat and productivity have been biased toward studies of vegetation rather than population response (Davies et al , Hess and Beck ).…”

“…However, wildfires differ from prescribed fires in timing, intensity, and size and may affect sage‐grouse populations more severely (Slater , Baker ). Recently, researchers have examined the demographic response of sage‐grouse to fire disturbance, and observed generally negative effects of large wildfire or prescribed fire on spring lek counts, recruitment rates, rate of population change (Blomberg et al , Connelly et al , Coates et al ), and sage‐grouse survival (Lockyer et al ).…”

A conservation planning tool for Greater Sage‐grouse using indices of species distribution, resilience, and resistance

“…Moreover, encountering pinyon-juniper can lead to more risk-prone behavior by Sage-grouse (Prochazka et al 2017), and selection of highly productive sagebrush habitat with scattered trees has negative fitness consequences for Sagegrouse (Coates et al 2017b). Invasion by annual grasses also diminishes habitat suitability by reducing available nesting cover and forage (Crawford et al 2004, Kirol et al 2012, Lockyer et al 2015, which can contribute to depressed population growth (Blomberg et al 2012).…”