|Title||Time series analysis of data from raingage networks in the Southwest|
|Publication Type||Conference Paper|
|Year of Publication||1995|
|Authors||Nichols M.H., Lane L.J., Gibbens, Robert P.|
|Conference Name||Wildland Shrub Symposium|
|Date Published||May 23-25, 1995|
The ability to evaluate shrubland ecosystem dynamics in a changing environment requires a historical perspective and quantitative analysis of precipitation as one of the primary ecosystem inputs. Historical time series of precipitation data collected from 24 raingages on the USDA Jornada Experimental Range since 1915 are examined. Time series analyses are conducted to test for trends, autocorrelation, and periodicities in the data and, thereby, an association between mean annual precipitation and time. These results are compared with precipitation data from the Walnut Gulch experimental Watershed in Southeastern Arizona and precipitation data collected over the southwestern region of the United States. Because segments of the historic record analyzed can reveal increasing annual precipitation, decreasing annual precipitation, or no trend in annual precipitation, caution must be exercised in attempting to assign either natural variations in weather and climate or rangeland use and management practices as the cause of changes in vegetation over time.