The Impact of Drought on Rangeland Productivity in New Mexico

Abstract:

Drought influences the vital ecosystem services that supply food, energy and water. In dryland ecosystems of the southwestern US, including New Mexico (NM), prolonged drought events have been common causing crop failure, rangeland degradation, wildlife and plant mortality. This study is conducted to provide an improved understanding of the relationships between drought and structural changes of NM’s rangelands (i.e., grassland and shrubland). This study is aimed to investigate the role of drought on rangeland structural changes and degradation. The study will use precipitation data from PRISM, vegetation data from Moderate Resolution Imaging Spectroradiometer (MODIS) and the Global Inventory Monitoring and Modeling System NDVI3rd generation (GIMMS NDVI3g) to calculate drought indices. Precipitation Condition Index (PCI), Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) will be derived from MODIS. A Principal Component Analysis (PCA) will be applied to derive Synthesized Drought Index (SDI). The Time Series Segmentation and Residual Trend analysis (TSS-RESTREND) will be utilized to detect structural change of rangelands. Pixels with significant structural changes from TSS RESTREND analysis will be identified to evaluate the prevalent statistical relationship between the year of degradation, drought occurrence, values of SDI and change vectors. The accuracy and consistency of SDI will be compared with other commonly used drought indices and agricultural production data. Preliminary results will be expected to characterize the relationship between drought, trend of rangeland productivity and surface temperature in NM.