INVESTIGATING CLIMATE DRIVERS OF GRASSLAND SPECIES DISTRIBUTIONS IN ILLINOIS AND MISSOURI

“Grassland” is a broad term that includes shortgrass and tallgrass prairies, marshes, and any other grass dominated ecosystem on relatively level landscapes in the mid-latitudes. Grasslands are some of the most productive and biodiverse ecosystems on Earth and have been significantly impacted by human influences. Three tallgrass species that can be indicators of grassland ecosystems in the Midwest United States are Andropogon gerardii, Panicum virgatum, and Sorghastrum nutans. The goal of the study was to validate a Maximum Entropy (MaxEnt) species distribution model for the three study species for 1950-2016, 1950-1983, and 1984-2016 and map those species’ distributions in Illinois and Missouri. Multiple statistical analyses were used to measure the model’s performance and climate variable importance on the study species predicted distributions. The MaxEnt model performed better than random for every study species in every period. MaxEnt’s mapped predicted species occurrences were compared to recent landcover images of the study area and the model’s predictions largely represent current landcover as well. Overall, variables that use both temperature and precipitation values such as vapor pressure deficits were the most important variables for species distributions. Understanding how climate variables impact species occurrences is extremely important in fields such as biology, conservation, and agriculture. Climate change is causing variables such as vapor pressure deficits to change and understanding how these alterations in climate will impact plant species and ecosystems is very valuable