Tim Delbridge
I attended the Oregon Cattlemen’s Association annual convention last week, in part to talk to ranchers about their experience operating in areas of wolf activity. While wolf management policy is often controversial, there isn’t much disagreement that the return of wolves to the Oregon landscape requires that ranchers adjust their management practices. Unfortunately, there is little research on the economic impact of wolf presence on individual livestock producers, mostly because of the difficulty in collecting data on all the direct and indirect ways that wolf-livestock interactions affect a ranching business. This is a gap that we are working to fill and in the meantime I will use this blog post to provide some background on the growth in wolf populations in the state and how those populations overlap with livestock grazing areas. I’ll also touch on the challenges associated with developing a richer understanding of the economics of the wolf issue in the western US.
Wolves returned to Oregon in 2009, and the population has been increasing since. Figure 1 shows the minimum wolf population over time in Oregon. The Oregon Department of Fish and Wildlife (ODFW) publicly releases these minimum known population numbers, along with GIS data showing the areas of known wolf activity (AKWAs) for each named pack, and reports of wolf depredation events (with exact locations withheld). Figure 2 shows a map with ODFW AKWAs for each named pack in 2022. The number of packs has increased significantly in recent years, with the highest wolf populations in the Northeast, but growing populations in Central and Southern Oregon.
With the spread of wolves across the state, there has been large increases in both the number of cattle grazing in areas of wolf activity as well as the density of wolves in affected grazing areas. Data from public grazing lands, while only one part of the grazing picture, provide useful insights into how the situation has evolved for Oregon ranchers in recent years. Figure 3 shows the increase in the number of livestock on public grazing lands that fall within an ODFW AKWA. This can be thought of as the number of cattle that are at risk of interaction with wolves while on the public allotment.
Interestingly, the wolf population density on public grazing allotments has grown at a faster rate than the number of cattle exposed to wolves. Figure 4 shows a measure of average wolf density on BLM and USFS allotments over time. The density of wolves increased by more than a factor of ten from 2011 to 2022 while the number of cattle grazing in an area of known wolf activity increased by a factor of six over this period. I calculated this density metric for each allotment by applying to it the density of an any overlapping AKWA. In the case that multiple packs were active on a single allotment, the allotment’s wolf density is the sum of the individual pack densities. This method is sensitive to ODFW estimates of a pack’s range, which may not be perfectly reflective of wolf hunting patterns in summer months when cattle are on the public lands.
While the most obvious impact of wolves on livestock is direct attack, there are several other ways that wolf presence can reduce ranching revenues and increase the cost of production. These include the labor costs associated with staying with and moving livestock to minimize interactions with wolves, and the cost of improved fencing, flags, and other materials that may deter wolves. Wolf related stress on cows and calves can result in reduced animal health and body condition, lower conception rates, and lower calf weight at the time of weaning or sale. These impacts likely exceed the cost of direct livestock kills, though we don’t have good data on how these costs vary from ranch to ranch and from year to year. The impact per producer or per head of cattle may be small when averaged over all livestock operations in the state, there can be very significant costs to individual ranches in affected areas.
Finally, Figure 5 shows the wolf density measure by grazing allotment in the form of a heat map for 2022. The next step in our economic analysis is to gather data on ranch level production costs and revenue reductions that are associated with different levels of wolf activity. We will then apply ranch-level impact estimates on maps of public and private grazing areas according to the density of wolves seen there. With this approach we will be able to produce an estimate for total statewide impact and provide guidance on how these impacts are distributed across the landscape and across Oregon’s cattle producers.