Download (PDF 96 KB): https://research.fs.usda.gov/download/treesearch/36011.pdf
Abstract
In 1934, Eragrostis lehmanniana was introduced into southeastern Arizona to control erosion and provide forage for cattle. The earliest of these introductions took place on the Santa Rita Experimental Range (SRER) in 1937 and continued there until the early 1960s. Numerous researchers have observed a convincing association between an increased proportion of E. lehmanniana and decreasing species richness in these grasslands. This grass is both invasive and persistent: just 50 years after its introduction, the area occupied by E. lehmanniana had doubled. Published evidence indicates that variables such as elevation, summer precipitation, winter temperatures, and soils impact its abundance and distribution. We used these variables to generate a map of current predicted distribution of E. lehmanniana. Using over 600 presence/absence points amassed from eight agencies in Arizona, we selected among the guidelines to create a current distribution map for E. lehmanniana in Arizona. We then modified this map using two common general circulation models developed by the Hadley Centre for Climate Prediction and Research and the Canadian Centre for Climate Modeling and Analysis to predict the potential distribution of E. lehmanniana in Arizona in the year 2030.
Parent Publication
Citation
Geiger, Erika; Mau-Crimmins, Theresa; Schussman, Heather. 2003. Spread of a nonnative grass across southern Arizona: Multiple data sources to monitor change. In: McClaran, Mitchel P.; Ffolliott, Peter F.; Edminster, Carleton B., tech. coords. Santa Rita Experimental Range: 100 years (1903 to 2003) of accomplishments and contributions; conference proceedings; 2003 October 30-November 1; Tucson, AZ. Proc. RMRS-P-30. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 116-120.
