Upper Mississippi River Restoration Program

Long Term Resource Monitoring

Landscape Indicators

Landscape Indicator Graphical Web Browser

Background

Landscape indicators are similar to other ecological indicators, such as those reported by the LTRM for fish, water quality, and submersed aquatic vegetation, in that they quantify key aspects of ecosystem structure or function. However, whereas ecological indicators typically use field observations to quantify patterns of organism abundance or concentrations of limiting nutrients, landscape indicators focus on the spatial arrangement of various land cover or habitat types using remotely sensed data. Landscape indicators are helpful in that they provide a larger-scale context for understanding potential constraints on nutrient or organism distributions. For this reason, the primary purpose of the metrics presented here is to provide resource managers and decision makers with information that can help them identify areas within the Upper Mississippi River that could benefit from restoration of major floodplain land cover and habitat types.

For example, floodplain land cover reflects the impacts of complex fluvial-geomorphic processes as well human land and water use (including restoration and management actions). The consequences of changes to floodplain land cover may include: changes in water quality as well aquatic and floodplain habitat amount and distribution, alteration of organic carbon and nutrient transfer between the river and floodplain, and changes to aquatic community compositions. To help resource managers understand and visualize patterns of floodplain land cover, we developed maps and metrics for land cover composition and diversity for three time periods (c. 1890, 1989, and 2000). For simplicity, land cover data were also condensed using multivariate analyses to show the primary changes in the most dominant land cover classes. See De Jager et al. (2011) for a full description of the methods used to develop these indicators.

Many management actions in the Upper Mississippi River (UMR) focus on the restoration of specific aquatic habitat types (e.g., side channels or backwater lakes). To help identify areas that could benefit from such actions, we developed a series of maps and metrics that characterize patterns of aquatic habitat diversity. For a full description of the methods used to develop these indicators, see De Jager and Rohweder (2011a).

Finally, the floodplain forests of the UMR provide important local breeding sites and a major migratory corridor for a variety of avian species. They also serve as buffers against non-point source pollution. Fragmentation of these forests could, therefore, alter the suitability of the floodplain for various resident and migratory bird species as well as impact water quality. To help forest managers identify areas for forest restoration, we developed a series of maps and metrics that characterize patterns of floodplain forest fragmentation. See De Jager and Rohweder (2011b) for a full description of the methods used to develop these metrics.

When using the Landscape Indicator Graphical Web Browser it is important to understand that results for any given metric will depend on the scale at which they are calculated and reported. The maximum spatial extent of this work was the entire length of the UMR (from Pool 3 near Minneapolis, Minnesota to the confluence with the Ohio River). This portion of the Mississippi River is often divided into navigation pools (the area between two consecutive dams). The indicators were reported as pool-wide estimates (e.g. proportion of the entire pool in a given land cover class) or as pool-wide means (e.g. aquatic area richness and forest fragmentation metrics). Results could vary substantially if pools were subdivided into smaller units, or if metrics were reported for larger river reaches containing multiple pools. For an even finer-scale examination of metric results, maps of the distribution of various landscape indicators can be viewed by clicking on data points within the graphs.

Literature Cited:

De Jager, N.R, Rohweder, J.J., and J.C. Nelson. 2011. Past and predicted future changes in the land cover of the Upper Mississippi River floodplain, USA. River Research and Applications. doi: 10.1002/rra.1615 (Abstract)

De Jager, N.R. and Rohweder, 2011a. Spatial Patterns of aquatic habitat richness in the Upper Mississippi River floodplain, USA. Ecological Indicators 13:275-283. (Abstract)

De Jager, N.R. and Rohweder, J.J. 2011b. Spatial scaling of core and dominant forest cover in the Upper Mississippi and Illinois River floodplains, USA. Landscape Ecology 26: 697-708 (Abstract)