The Carrizo Plain is one of the largest relatively intact portions of the San Joaquin Desert, and hosts high levels of endemic species threatened by habitat loss. The endangered giant kangaroo rat (Dipodomys ingens) is at the center of this ecosystem, but management decisions regarding this and other threatened species such as the San Joaquin Antelope Squirrel (Ammospermophilus nelsoni) require long-term research to inform them. In collaboration with the Nature Conservancy, California Department of Fish & Wildlife, and the Bureau of Land Management, the Carrizo Plain Ecosystem Project (CPEP) was established to better understand these two imperiled species. Here we will present our findings after monitoring giant kangaroo rat and San Joaquin antelope squirrel populations on the Carrizo Plain for 19 years, with an emphasis on elucidating the influence cattle grazing may have on the populations of these two rodents after wet winters with abundant vegetation. Though the impacts of low-intensity grazing may be small in magnitude, they are important to understand as managers consider the utility of grazing to influence threatened small mammal populations in the future.