Floodplain ecosystem response to climate variability and land-cover and land-use change in Lower Missouri River basin

摘要

This contribution aims at characterizing the extreme responses of Lower Missouri River basin ecosystems to land use modification and climate change over a 30-year temporal extent, using long term Landsat data archives spanning from 1975 to 2010. The inter-annual coefficient of variation (CoV) of normalized difference vegetation index was used as a measure of vegetation dynamics to address ecological consequences associated with climate change and the impact of land-cover/land-use change. The slope of a linear regression of inter-annual CoV over the entire time span was used as a sustainability indicator to assess the trend of vegetation dynamics from 1975 to 2010. Deduced vegetation dynamics were then associated with precipitation patterns, land surface temperature, and the impact of levees on alluvial hydrologic partitioning and river channelization reflecting the links between society and natural systems. The results show, a higher inter-annual accumulated vegetation index, and lower inter-annual CoV distributed over the uplands remaining virtually stable over the time frame investigated; relatively low vegetation index with larger CoV was observed over lowlands, indicating that climate change was not the only factor affecting ecosystem alterations in the Missouri River floodplain. We cautiously conclude that river channelization, suburbanization and agricultural activities were the possible potential driving forces behind vegetation cover alteration and habitat fragmentation on the Lower Missouri River floodplain.