| Abstrakt: |
Agricultural expansion in native prairie may damage or destroy vegetation normally used for nesting, brood-rearing, and winter habitat for Sharp-tailed Grouse (Tympanuchus phasianellus) Understanding the interaction between Sharp-tailed Grouse and their human-modified prairie habitat is vital for predicting potential population declines and working toward preventing losses similar to what has occurred with sage grouse, Cent rocercus spp. We designed a rigorous method to survey for Sharp-tailed Grouse leks over broad spatial extents in east central Alberta. We used historic lek location data from 1958-2005 to build two complementary models that first predict lek occurrence and then estimate the density of leks among stratified areas of the region. We used a resource selection function (RSF) to predict lek occurrence and a distance sampling approach to estimate lek density. The RSF was based on the availability of habitat features (ia, grassland, crop, shrubs, trees) and enabled us to stratify our area into high, medium, and low classes by the likelihood of a lek being present. We surveyed 630 random sites near sunrise in the springs of 2006-2008, roughly 18% of the 26,000 km2 region, and located 146 new leks. Our predictions of where leks would occur were roughly validated by the proportion of leks newly discovered among the three classes. Our distance function was derived using a modified point-count method allowing us to estimate the density of leks in each stratum, ranging from 0.017 leks/km2 to 0.048 leks/km2 in the low and high classes, respectively. Our approach provides an efficient means for predicting lek occurrence based on habitat features and for using this information to estimate lek density across vast spatial extents. [ABSTRACT FROM AUTHOR] |
