Chapter Two. Hierarchical Modeling of Lek Habitats of Greater Prairie-Chickens

Abstract

Greater Prairie-Chickens ( Tympanuchus cupido) are a lek-mating prairie grouse of the central Great Plains. Males gather each spring at communal display grounds or leks to compete for mating opportunities with females, and lek sites are essential for the reproductive biology of prai- rie-chickens. We obtained geographic coordinates for 166 active leks located in eastern Kansas. Using GIS analysis, we developed a spatially explicit model to identify landcover and geomorphological variables associated with lek locations. We used a hierarchical approach to model selection to iden- tify the best predictor variables at three spatial scales (0 m, 200 m, and 5 km), and then combined factors from the best models into a global multi- scale model. We found that a synthetic variable, weighted elevation or the point elevation stand- ardized by the elevation of the surrounding land- scape, best explained lek occurrence at a lek point scale of 0 m. At broader spatial scales of 200 m and 5 km, avoidance of agricultural, urban, and forest habitats, avoidance of high densities of roads, and a preference for grassland cover were the best predictors of lek site locations. Next, we created an entropy model based on factors from our minimum Bayesian Information Criterion global model to create an index of suitable lek hab- itat across the Flint Hills, Smoky Hills, and Osage Plains ecoregions of eastern Kansas. The entropy model showed that 85% of lek sites were in hab- itat strata that comprised 20% of the regional landscape, suggesting that prairie-chickens may be utilizing areas that are of marginal quality. Our research results have important implications for conservation because Kansas prairies are the core of extant distribution of Greater Prairie-Chickens and include the largest remaining intact grass- lands in the United States.