A spatial risk assessment of bighorn sheep extirpation by grazing domestic sheep on public lands.

摘要: a b s t r c Bighorn sheep currently occupy just 30% of their historic distribution, and persist in popula- tions less than 5% as abundant overall early 19th century counterparts. Present-day recovery bighorn populations is large part limited by periodic outbreaks respi- ratory disease, which can be transmitted to via contact with domestic grazing vicinity. In order assess the viability on Payette National Forest (PNF) under several alternative proposals for grazing, we developed series interlinked models. Using telemetry habitat data, characterized herd home ranges foray movements from ranges. Combining model movement estimates known areas (allotments), Risk Contact Model estimated rates allotments. Finally, used demographic epidemiologic data construct population disease transmission models (Disease Model), estimate persistence each scenario. Depend- ing probability following interspecies contact, extirpation probabilities seven herds examined here ranged 20% 100%. The Disease allowed us that varied man- agement scenarios would support persistent free-ranging sheep.