Estimating Historical Sage-Grouse Habitat Abundance Using a State-and-Transition Model

摘要: Use of reference conditions to compare current what managers believed represented healthy and functioning systems has become a common approach evaluate vegetation habitat aid development land management plans. Often attempt describe landscapes as they existed functioned prior about 1850, often largely rely on expert opinion. We developed for sagebrush (Artemisia spp. L.) ecosystems in eastern Oregon based ecological site descriptions, soil surveys, climate data, wildfire records, opinion, literature using state-and-transition (STM) modeling framework. Using descriptions the Malheur High Plateau Major Land Resource Area (MHP), we divided communities into four groups grass productivity low, average high years. Literature helped us determine which disturbance factors include, community phases each model, associated seasonal greater sage-grouse (Centrocercus urophasianus). successional timelines absence disturbance, determined probable outcomes given type event. used fire records data develop event probabilities periodicities. Contrary our expectations, did not appear be most important factor influencing under models. The modeled historical abundance breeding brood-rearing was within range or than amount recommended by biologists, but wintering less. By objective criteria much possible, should also repeatable other locations. Since define probabilities, models provide an opportunity examine how changes could affect plant communities, regimes, quality quantity future efforts. ____________________________________ In Monaco, T.A. et al. comps. 2011. Proceedings – Threats Shrubland Ecosystem Integrity; 2010 May 18-20; Logan, UT. Natural Resources Environmental Issues, Volume XVII. S.J. Jessie E. Quinney Research Library, Logan Utah, USA.