Seasonal and Interspecific Landscape Use of Sympatric Greater Prairie-Chickens and Plains Sharp-tailed Grouse

摘要

Native grasslands throughout the Great Plains, USA, have undergone varying levels of fragmentation. The prairie ecosystems of Nebraska, USA, provide habitat for culturally and economically important galliforms, including greater prairie-chicken (GRPC;Tympanuchus cupido pinnatus) and plains sharp-tailed grouse (STGR; Tympanuchus phasianellus jamesi). The Sandhills region in north-central Nebraska remains largely intact as grasslands, but cropland development at the margins has provided potential foralternative winter forage sites. Our objectives were to describe intraspecific seasonal shifts and inter-specificdifferences in landscape use of these 2 species of prairie grouse in the Sandhills. We captured and radiomarked 87 birds (68 STGR, 19 GRPC) during 2015-2016 and used aerial telemetry to collect location data on birds. We used presence-only location data and ecological and anthropogenic variables (e.g., land-cover types, topography, vegetation productivity, and roads) in a maximum entropy (using MaxEnt software) approach to construct and compare seasonal species distribution models. During the breeding season, GRPC distribution probabilities were greater in areas more distant from center-pivot irrigation locations, proximate to wet meadows, and at moderate distances from crop fields, whereas during the nonbreeding season, distributions were positively influenced by conifer and mixed-grass (generally areas on peripheries of wetlands or meadows) land-cover types. For STGR during both seasons,distribution probabilities were greatest in areas more distant from wet meadows, whereas during the nonbreeding season the probabilities were also greater in areas more distant from sandy ecological sites. Using an ecological-niche-similarity approach toexamine interspecific use of the landscape, we found evidence that landscape use on our study area differed between species during the breeding season, but not during the nonbreeding season. Our results provide support for coordinated, landscape-level management of galliforms, which can now be extended to seasonal priorities during management decisions on publicly and privately managedlands.