Photo credit: Vivian Hawkinson
By Vivian F. Hawkinson, Oswald J. Schmitz, and Kristy M. Ferraro.
The return of gray wolves to their historic range across Europe and North America through reintroduction or range expansion has led to increased concern over interactions with livestock. While much attention has been given to the variations in local environment that influence predation of livestock (distance to the nearest road, tree cover, etc.), the role of landscape-level features like the availability of wildlife habitat, or the degree of wildlife habitat fragmentation, has not been explored as extensively. Moreover, how different livestock management practices interact with these landscape-level variables remains unclear.
To address this, we created a model to simulate how a wolf pack hunts in a landscape that includes herds of cattle, wild prey species like deer and elk, and both privately owned farmland and publicly managed wildlife habitat. We then examined how the use of three different cattle grazing practices affected interactions between the simulated wolves, cattle, and wild prey over the course of a year. We also explored how changes in the size and connectivity of areas of wildlife habitat on our simulated landscapes influenced these interactions.
We found that when areas of wildlife habitat were larger and more connected, livestock deaths decreased because the wolves had better access to their natural prey. In highly fragmented landscapes this trend broke down, and interaction rates between cattle, wolves, and wild prey species became highly unpredictable. While the overall number of livestock deaths didn’t vary widely between the three different cattle grazing practices, the location of wolf kills did. For example, most livestock deaths in the seasonal grazing scenarios, where our simulated cattle spent six months grazing on publicly managed wildlife habitat before being moved back to privately owned pasture for fall and winter, happened while cattle were grazing on wildlife habitat, highlighting the risks associated with using areas where overlap with wolves is more likely.
This research suggests that efforts to restore and maintain connected landscapes can help reduce interactions between wolves and livestock. By ensuring wolves have access to their natural prey, livestock operations may experience fewer losses. Additionally, increasing the accessibility and affordability of wolf deterrents and removing attractants, like the carcasses of dead cattle, will aid in reducing conflicts in locations where preservation or restoration of landscapes either is not possible or does not yield fewer livestock deaths.
Relational Thinking 