In 1968 and early 1970s, several grazing systems based on rest rotation principles, designed by Gus Hormay, were put in place on the Strip. One grazing system is in the Mojave Desert, the 36000 acre Beaver Dam Allotment, has been in effect since 1974. The other two grazing systems have been in effect since 1968. The  Clayhole, a 150,000 acre allotment, is in Great Basin desert shrub and grassland plant communities. The other one is Little Tank Allotment, which is 6000 acres, and it is in the desert grassland. The latter two were used yearlong by cattle. Beaver Dam was used in the winter and spring. The systems were run according to their plans until the early to mid-1990s. Changes brought on by new livestock ownership and by constraints for the desert tortoise occurred.

Trend and utilization data have been gathered since 1968 and used to make adjustments in grazing along with the above changes. Trend data will be looked at along with utilization to tease out what weather affects and what grazing management has affected over the years. Weather is the most powerful element to deal with in species composition trend changes, but utilization has an affect also.  Have the grazing systems had the desired affects??  In general, the allotments observed are in the late seral stages of ecological succession and trend of the forage and non-forage species have maintained a desirable frequency or composition, as long as utilization stays light  to moderate levels. 

These will discussed in light of the long drought currently in place in the Southwestern United States.