Benefits of risk mapping for mitigating human-carnivore conflicts

Over the past few decades, human-carnivore conflicts have received increasing attention worldwide as most large carnivore populations continue to decline. Many carnivores have large territories and specialize in ungulate... [ view full abstract ]

Over the past few decades, human-carnivore conflicts have received increasing attention worldwide as most large carnivore populations continue to decline. Many carnivores have large territories and specialize in ungulate predation, consequently, some kill domestic livestock when the opportunity arises. Preventing carnivore-livestock interactions requires identifying conditions placing livestock at risk and focusing outreach and adaptive management at a local scale. Risk mapping has become a popular method to display potential hotspots for livestock depredations by carnivores. To date no maps predicting livestock depredation risk exist for the gray wolf (Canis lupus) population in the northern Rocky Mountains and surrounding region of the United States. I used historical data (i.e. 1991 – 2008) from Idaho and Montana to predict cattle (Bos taurus) depredation risk by a recolonizing wolf population in Washington. Risk models were developed at two spatial scales, (1) wolf pack territory (n = 137) and (2) cattle grazing allotment (n = 69) to test hypotheses that cattle depredations by wolves were associated with wolf demographics, cattle and wild prey abundance, allotment characteristics, and land cover types. Within wolf pack territories, cattle depredation risk increased as cattle abundance and adult wolf removal increased and if the pack depredated the previous year. Adult wolf removal and pack size showed weaker evidence in their relationship with cattle depredation probability and the predicted number of cattle depredated. Similarly, cattle depredation risk increased for larger grazing allotments with more cattle, wolves, and grassland cover and decreased with pack reproduction and a later cattle turnout date. Wolf pack reproduction, cattle turnout date, and percent grassland cover showed high variability in the direction of their relationship with cattle depredation probability and the predicted number of cattle depredated. Forecast maps for Washington identified hotspots of high (81 – 90%) depredation risk in Yakima, Kittitas, and Columbia counties. Cattle grazing allotments only occur east of the Cascade Mountains, and hotspots in Okanogan, Ferry, and Yakima counties were recognized as intermediate (61 – 80%) depredation risk. These risk models and maps provide locations to focus depredation prevention measures and a template for future analyses as wolves continue to recolonize Washington.