Current ecological conditions

Describing the status of the Upper Mississippi River is a
continuing function of the Long Term Resource Monitoring Program. 
Some ecologically important characteristics that serve as indices
of overall system status include depositional habitats,
vegetation, invertebrates, fish biodiversity, and our capability
to apply information to achieve ecological goals.  Individual
conditions, however, must be regarded as elements of a
comprehensive ecological perspective.  The filling of depositional
aquatic habitats has been measured sufficiently to identify this
as the major long term resource problem in navigation pools. 
However, extrapolating sedimentation rates from one location to
another for the purpose of focusing rehabilitation efforts is
problematic without additional hydrologic information.  Many
depositional habitats currently are at high risk of entering a
successional phase that will be characterized by poor water
quality and reduced aquatic vegetation.  Changes in the abundance
of submersed vegetation and invertebrates have been linked to
droughts and floods, among other factors, recently, but the
interpretation of long term trends is still limited by the short
periods of time over which comparable observations have been made
and a lack of experimental research.  Zebra mussels pose a serious
threat to native mussel populations, and their already widespread
occurrence suggests that we need to shift our efforts from
monitoring to identifying practical control measures. 
Biodiversity (species richness) of the fish community has declined
less than that of the mussel community.  Our capability to utilize
ecological information in a proactive management strategy is
improving.  One of the first steps in the strategy will be the
establishment of ecological objectives and action levels
appropriate for a large floodplain river.