Efforts to distinguish the effects of land management on ecosystem performance are difficult due to the confounding effect of interannual weather variation on productivity. The current study overcomes this issue by comparing the difference between actual and expected ecosystem performance (EEP) to generate maps of ecosystem performance anomalies (EPA). We aimed to determine EPA from 2000 to 2009 within the greater Platte and upper Colorado River basins at 250 meter resolution to serve as a proxy for range condition and quantify the influence of disturbance and land management on productivity. Yearly EEP was determined through regression tree analysis of abiotic data (e.g. weather, soils, elevation, etc.). Moderate Resolution Imaging Spectrometer (MODIS) Normalized Difference Vegetation Index (NDVI) data were averaged over the growing season (GSN) and served as a proxy of actual ecosystem performance. Validation revealed that EPA values were strongly related to biomass production (R2 = 0.56, P = 0.02) and likely the proportion of biomass removed by livestock. These results show that 60.6% of the study area was performing near its EEP, 3.0% of the study area was severely underperforming, 5.0% was highly overperforming, and the remainder was either slightly underperforming or overperforming. We have developed an interactive online tool that enables users to visualize EPA and plot its change over time for any available area. These data and tools enable land managers to evaluate the status of ecosystem productivity and practice adaptive management.
ECOSYSTEM PERFORMANCE AND ANOMALIES IN THE GREATER PLATTE AND UPPER COLORADO BASINS, USA
Matthew Rigge1, Bruce Wylie2, Yingxin Gu1, Jayne Belnap3, Khem Phuyal4, Larry Tieszen2 --- 1Arctic Slope Regional Corporation Research & Technology Solutions, Contractor to USGS EROS Center, Sioux Falls, SD, USA, 2USGS EROS Center, Sioux Falls, SD, USA, 3USGS Southwest Biological Science Center, Moab,UT, USA, 4Stinger Ghaffarian Technologies, Contractor to USGS EROS Center, Sioux Falls, SD, USA