Agroecosystem and Ecosystem Resiliency to Extreme Hydrometeorological and Climate Events

The purpose of this study was to understand how a large-scale representation of agroecosystems and ecosystems respond to extreme hydrometeorological and climate extreme events (EHCE) within the Platte River Basin. The ability for agroecosystems and ecosystems to adapt to a changing and variable climate is vital for global water, energy, and food security. Two model experiments were performed, the first with a time span from 2000 to 2013 in which a dynamic leaf area index (LAI) MODIS15A2 product was implemented. The second experiment ran from 1950 through 2013 used a climatological fixed seasonal cycle calculated as the average from the 2000-2013 dynamic MODIS15A2 product. The Variable Infiltration Capacity model (VIC) was employed for the two experiments to simulate evapotranspiration (ET) and soil moisture. Soil moisture percentiles were found for the Platte River Basin along with the five main subbasins, North Platte, South Platte, Middle-Lower Platte, Loup and Elkhorn. Extreme wet and dry events were identified and assessed based on the soil moisture percentiles and a threshold of above 80% and below 20%, respectively. The Platte River Basin was discretized into the two major land covers, agriculture (agroecosystems) and grassland/shrubland (ecosystems). The dynamic LAI was examined between the two land covers and utilized as a representation for system function along with evapotranspiration and soil moisture for defining resilience. Resilience was measured for the two land covers based on the deviation and recovery time for the three system functions. For both wet and dry extreme events, the agroecosystem was found to be more resilient than the ecosystem. Advisor: Francisco Munoz-Arriol