Assessment of Spatial Metrics to Determine Rangeland Degradation Riaz Hedayati Mentor: Chandra Holifield Collins USDA-ARS SWRC The University of Arizona April 17, 2010
Background Soil erosion is a major cause of degradation in rangelands. If erosion patterns can be predicted, rangeland degradation can be more easily prevented. Traditionally, erosion potential is assessed using one of two ground-based measurements on a 2m x 6m plot: Transect Data (fetch:patch ratio) Point Data
Hypothesis Accounting for the spatial distribution of vegetation cover will be an improvement over traditional ground-based data for predicting erosion potential.
Study Sites Data was collected from 5 different field sites within southeastern Arizona. Each field site had 4 plots, and each plot measured 2m x 6m.
Methods A rainfall simulator was used on each plot to simulate erosion patterns and collect sediment yield (SYR) data.
Methods Point Interspace Area SYR Point Interspace Area
Methods Fetch:Patch Ratio SYR Fetch:Patch Ratio
Methods Photographs were digitally classified into vegetation and non-vegetation areas. Interspace FPI SYR Interspace FPI
Sediment Yield vs Point Data
Sediment Yield vs Fetch:Patch Ratio
Sediment Yield vs Interspace FPI
Conclusions Interspace FPI showed a slightly stronger relationship to sediment yield data than the point data or the fetch:patch ratio. Because it explicitly accounts for the spatial distribution of interspace areas, interspace FPI shows great promise as a tool for assessing degradation of ecological sites in semi-arid rangelands.
Dr. Chandra Holifield Collins Acknowledgements This Project would not have been possible without help from: Dr. Chandra Holifield Collins Dr. Jeffry Stone Rae-Landa Gomez-Pond Leonard Cratic III Jason Wong
Thank You