Recent trends in the climate lead to predictions of significant change in both precipitation and temperature for the Midwestern states of the United States. These changes in our climate are bound to bring about changes in the functioning of all ecosystems. Due to its rarity at a global scale, the prairie ecosystem poses a particular concern in this situation. Our ability to look at this problem from a landscape level has been greatly enhanced through developments in remote sensing technologies.
Geographic locations of prairies in the Midwest were obtained from local state and non-governmental agencies for use in a geographic information system. These files were screened to ensure that the prairies met both size and vegetation requirements. The prairie outlines were then overlaid on eight years of MODIS imagery in eight-day composites as to extract each prairies NDVI time series. Several factors including growing season length and Time Integrated NDVI (TINDVI) were determined using simple phenological functions. These factors were then compared against precipitation, minimum and maximum temperatures, as well as snow data obtained from the National Climatic Data Center.
Results/Conclusions
Preliminary results of this study show that prairie inter-growing season minimum temperatures influences the start of the growing season while the end of the growing season precipitation is most correlated with the end of the growing season. Initial analyses of TINDVI indicate some influence from these same factors. Current predictions of climate change estimate increases in precipitation of 25% and increases in temperatures of nearly 2oC. This may mean cause significant alterations in function for Midwestern prairies.
