— Figuring in dietary overlap can help with rangeland management decisions
A new research publication out of the University of Wyoming sheds some light on grazing competition between livestock and wildlife in the West. The difference in dietary needs of grazers, domestic and wild, can help inform rangeland management.
The bulletin—“Dietary composition and conflicts of livestock and wildlife on rangeland”—was written by Derek Scasta, Assistant Professor and Extension Rangeland Specialist. It focused on where the dietary needs of different grazers of the West overlap and potentially cause conflict. The report compiled data from 33 different scientific studies, covering 208 different samples from 12 different western states plus Canada.
“The interaction of livestock and wildlife on rangeland is an issue of concern not only for ranchers and wildlife managers, but the general public,” wrote Scasta. “Recently, the public interest in the ecological impacts and well-being of wild horses on western rangelands has raised additional concerns.”
different physical differences between cattle, wild horses, elk, mule
deer, domestic sheep, and pronghorns, Scasta pointed out the different
diet trends of each animal. They are as follows:
• Cattle; 74 percent grass, 14 percent shrubs, 12 percent forbs.
• Wild horses; 82 percent grass, 10 percent forbs, 8 percent shrubs.
• Elk; 47 percent grass, 30 percent shrubs, 23 percent forbs.
• Mule deer; 72 percent shrubs, 22 percent forbs, 6 percent grass.
• Domestic sheep; 42 percent grass, 38 percent forbs, 20 percent shrubs.
• Pronghorns; 58 percent shrubs, 34 percent forbs, 8 percent grass.
These percentages of course vary based on time of year, area, precipitation, and other variables.
From these breakdowns, cattle and wild horses compete most fiercely over grass, elk and sheep have similar needs at somewhat similar times, and mule deer and pronghorns vie for access to shrubs.
“Understanding the dietary composition of wildlife and livestock on western rangelands is critical for balancing livestock production with wildlife conservation,” noted Scasta.
He also pointed out that a number of factors can influence the intensity of the conflict between competing species. Among these include the time of year the animals occupy a shared territory, population changes over time, the relative availability and nutritional quality of plants on the range, and past management, which can impact plant diversity and vitality. Keeping these details in mind is essential when using grazing for specific management goals.
“Management objectives might include enhancing wildlife habitat with livestock grazing, targeted grazing for invasive plant management, understanding the response of wildlife to rangeland improvement projects, and managing for multiple species and multiple objectives.”
To read the full report, visit wyoextension.org/publications/ and search for “B- 1260.” — WLJ