Predicting the Impact of Climate Change on Cheat Grass (Bromus techtorum) Invasibility for Northern Utah: A GIS and Remote Sensing Approach

Cheat grass (Bromus tectorum) invasibility represents a serious threat to natural ecosystems dominated by sagebrush (Artemisia tridentata). Ecosystem susceptibility to annual grass invasion seems to be driven by specific biophysical conditions. The study was conducted in Rich County, Utah, where cheat grass invasion is not yet an apparent problem, but an imminent invasion might be just a matter of time (temporal scale) to meet spatial variations in environmental conditions (spatial scale). Literature review and expert knowledge were use to define biophysical variables and their respective suitability ranges of where cheat grass takeover might occur. Ordination and Logistic Regression-statistical analyzes were used to estimate cheat grass invasion probability along environmental gradients. GIS procedures were used to spatially predict areas prone to be invaded by cheat grass at present climatic conditions. Afterwards, simulated climatic change projections (for 2099 year) from the Community Climatic System Model (CCSM-3) were used to model the invasibility risk of Cheat grass. Final results showed that the rangelands of Northern Utah might be at great risk of being affected by cheat grass invasion not only if current conditions persist but also if the climate changes occur as predicted by the CCSM model. The location of highly predisposed areas can be useful to alert managers and define where resources might be allocated to reduce a potential invasion and preserve native rangeland ecosystems