Upper Midwest Environmental Sciences Center
Habitat Needs Assessment for the Upper Mississippi River System
The HNA provides volumes of data concerning historic, existing, predicted future conditions, and desired future conditions that were all used to compile UMRS habitat needs. Habitat need expressed at system-wide, reach, or even whole pool scales, is too broad for developing detailed habitat project plans, but the HNA can be used to determine the degree to which individual projects meet the habitat protection and restoration objectives expressed at broader scales.
A step-by-step use of HNA products in HREP planning and prioritization might include the following steps that will be described in greater detail below:
The HNA allows each of these steps to be addressed in a quantitative or qualitative fashion. Using the full range of GIS data available and advanced modeling tools developed for the HNA, program managers might assess historic, existing, and future habitat value for distinct project areas. Future habitat value can be calculated by creating GIS layers that simulate post project physical conditions and anticipated plant community response.
1. Historical data.
GIS data sets are available for presettlement land cover conditions for about one-third of the UMRS, with most major reaches represented. 1890s land cover data are available for the entire UMRS, and comparable maps can be created for the Illinois River. The Cumulative Effects study provides map and photo derived acreage estimates of major aquatic areas classes for predam, immediate post dam, and modern conditions for most areas. Similar information can be compiled in greater detail when working in discrete locations such as HREP project boundaries.These data can be clipped to fit project area boundaries, or can be used to calculate the abundance of major land cover classes for larger areas likely to be influenced by a project or used in planning (i.e., pool scale). Historic land cover can be compared to existing and desired to help determine what communities were once present, and which might be most likely to thrive in an area. Large-scale habitat manipulation, (i.e., dams) however, may have altered historic conditions such that historic conditions cannot be supported. Immediate post dam conditions may be the most applicable time step for project planning in areas highly influenced by dams. High elevation floodplains less influenced by impoundment may be able to be restored to presettlement conditions.2. Existing conditions
Existing land cover conditions have been compiled and summarized for the entire UMRS, and some areas have significant additional depth, flow, water quality, etc. data. These data can be easily summarized for project area boundaries to help develop projects, to help develop project expectations, and for comparison with historic or predicted conditions.3. Future conditions
Future conditions have been quantitatively predicted for most of the UMRS and qualitatively predicted for the entire river. Quantitative predictions are not spatially explicit, but a project's, or multiple projects', influence on changing future conditions of major aquatic habitat classes could be estimated for regions as small as upper or lower pool reaches. The precision of predicted or project induced change may be quite low, thus changes may have to be large to be detectable.Maps developed to express resource manager's projected habitat change are very spatially explicit. They are particularly useful because they identify the dominant geomorphic processes influencing habitat development in an area. Knowing what processes are affecting an area is critical to project design.4. Desired future condition
Desired future conditions were not expressed in a spatially explicit fashion, so it is difficult to use them to develop or assess individual projects. The aquatic areas affected by a project can, however, be compared to desired conditions for an entire pool to see how they fulfill a need. The influence of multiple projects can summed to determine what level of habitat protection or restoration is necessary to fulfill the desired future at the pool scale. Desired land cover conditions were not clearly expressed, but resource managers thought increased diversity of native land cover classes and recovery of aquatic plant communities were very important.
Using GIS Tools
The HNA basic and advanced GIS query tools provide many of the resources necessary to assess historic and existing conditions. The advanced query tool can be used to easily incorporate multiple data sets, clip polygons and summarize land cover or potential habitat value, and importantly, to allow users to create their own habitat models. Other GIS tools available to advanced GIS programmers can be used to simulate habitat project physical attributes and their anticipated plant community effects in the GIS. The simulation(s) can be used to calculate land cover or potential habitat created by an individual, or multiple, habitat projects.