Great Rivers Partnership - UMR-Ecological Threats

The Upper Mississippi River Program

Ecological Threats

The Nature Conservancy’s Upper Mississippi River Program has determined that the following issues have major consequences for native habitats within the UMR region:

• Altered river flows. Human impacts have changed water flow regimes. For example, locks and dams on the Upper Mississippi and Illinois rivers have established navigation pools of sufficient depth to create a waterway transportation system. However, with the water constantly maintained at low-flood stage, many acres of floodplain, side channel, back water and island habitats are being slowly degraded.

• Isolated floodplains. Levees along the Upper Mississippi and Illinois rivers prevent seasonal floodwaters from reaching much of the rivers’ original floodplains, thus isolating a critical component of riverine habitat. These changes also diminish river function by interrupting and altering the flow of sediment.

• Loss of habitat. About 66 percent of the UMR basin has been converted from native prairie, savannah and forest habitats to agricultural use. In much of this altered landscape, increased runoff carries excessive levels of nutrient and sediment downstream, degrading water quality and in-channel habitat.

• Invasive species. Invasive species place further stress on declining native species, generally through direct competition. Sometimes they stress habitats themselves through sheer numbers. Invasives of particular concern in the UMR basin include silver and bighead carp and zebra mussel.

• Climate change. Human-induced climate change will likely affect freshwater habitats in the UMR region by altering snowfall, rainfall and temperature patterns. These changes could well lead to regional extirpations of native plants and animals and dramatic shifts in vegetation types.

Savannah Bluff Lock and Dam

UMR Program

Priority Sites