Wild Utah Project's Forage Analysis and Capacity Model

Since 2002 Wild Utah Project has been working to develop a new tool to assess the livestock grazing carrying capacity of allotments in a manner consistent with the current national rangeland health standards and guidelines. The Bureau of Land Management's (BLM) current method dates back several decades and fails to consider the needs of wildlife and their habitats. The BLM rarely assesses the capacity of an allotment when making grazing decisions. But when it does, such an assessment is based on forage production of a few perennial grasses preferred by cattle. Unfortunately, this method leads to overgrazing in riparian areas, shifts in plant community composition, loss of soil cover and litter, and long-term loss of range productivity for wildlife.

The Wild Utah Project's new alternative "grazing capacity formula" updates the formula BLM uses to bring grazing capacity estimation in line with the agency's rangeland health standards. In 2001, the Wild Utah Project and one of our conservation partners, the Western Watersheds Project, field-tested a prototype method we are now using to determine the amount of forage typically available at the end of the growing season on Utah's arid (sagebrush and saltbush) rangelands. Designing this new field method involved analyzing past BLM range capacity estimates of our test allotment, and - using similar transect and plot survey methods used by most range managers - conducting our own forage clipping surveys to directly measure the amount of forage in the test allotment.

In 2003 we then turned to the scientific literature to help us come up with a formula that calculates the amount of forage that needs to remain on the land to ensure enough vegetation coverage to: (1) resist soil erosion, (2) provide food and cover for all native wildlife, and (3) ensure resiliency of the vegetative community in the face of possible drought. Our new grazing capacity formula is coupled with a GIS analysis to determine remaining forage on an allotment based on either clipping studies from that allotment, extrapolations from our clipping plots, or other generic productivity data supplied by the Natural Resource Conservation Service. Our new formula then helps determine which rangelands are suitable for livestock grazing, and if suitable, at what level. Overall, our forage analysis/capacity model is relevant to the lower elevation, upland systems of the Colorado Plateau parts of the Wyoming Basins Ecoregion, and allows the user to calculate an adjusted cattle stocking rate that is more compatible with the needs of the fragile and sensitive vegetative and wildlife communities of this region.

As with our ongoing work to develop new methods for assessing stream and riparian health, we are now in the stage of working to convince the BLM and the Forest Service to adopt part or all of our new forage/capacity model in their grazing management programs. We are engaging in public stakeholder processes with the agency and bringing out model (and our own field data!) to the table. We are trying to put some scientific and public pressure on the agencies by presenting our new capacity protocol at scientific conferences, and publishing it in a scientific journal. Additionally, our research suggests that grazing has caused severe impairment of the forage productivity of these extremely sensitive Utah lands. The BLM is mandated by law to prevent permanent productivity. By highlighting BLM's failure to prevent permanent impairment of productivity by setting stocking rates too high, Wild Utah Project and our partners are using the carrot (pushing sound science), and stick (potential legal action over loss of productivity by our conservation partners) to further convince the agencies to adopt our new method when setting livestock stocking rates across Utah's sensitive ecoregions.

Please click HERE to download "Wild Utah Project's Forage Analysis and Capacity Model" Report