Great River Greening | Natural Plant Communities

ECOLOGICAL RANKING OF SITES IN THE LOWER MINNESOTA AND ST. CROIX RIVER VALLEYS

Ecological Ranking Protocol
Lower Minnesota River Valley Ecological Ranking
Lower St. Croix River Valley Ecological Ranking

Conservation Opportunities In the Minnesota and St. Croix River Valleys in The Twin Cities Metropolitan Area (.doc format)

LAND COVER INVENTORY - THE MLCCS

What Is the MLCCS?

The Minnesota Land Cover Classification System (MLCCS) provides a method of describing any parcel of land in terms of its vegetation (or lack of it) and the amount of impervious surface (such as pavement and buildings) present. It was developed cooperatively by these agencies and organizations:

Great River Greening
Minnesota Department of Natural Resources (DNR)
Dakota County Soil and Water Conservation District (Dakota SWCD)
Mississippi National River and Recreation Area, National Park Service
Friends of the Mississippi River

Before the MLCCS was developed, many important questions could not be answered, including:

What natural vegetation remains, besides the high-quality remnants mapped by the Minnesota County Biological Survey?
Where are degraded natural sites that would benefit from restoration efforts?
What types of vegetation grow on degraded sites?
What native plant communities should be restored to these sites?
How much impervious surface covers each watershed?

To answer questions like these, every square inch of the landscape must be mapped using a consistent classification system. The Metropolitan Council has a system to classify land use (such as parks and recreation, multi-family residential and vacant), but it does not indicate the type of vegetation present. The DNR Natural Heritage Program has a system to classify native plant communities, but it is not applicable to highly disturbed areas.

The MLCCS generally classifies native plant communities according to the DNR system. But for developed areas and disturbed vegetation, the MLCCS uses a completely new system, combining elements from several other classifications. The MLCCS uses names familiar to many Minnesotans, such as oak forest, but also new classifications, such as short grasses and mixed trees with 26%-50% impervious cover.

How Does Great River Greening Use the MLCCS?
Great River Greening collaborated with the DNR, Dakota SWCD and USFWS for the first application of the MLCCS. In 1999 and 2000 we mapped 109,000 acres in the metro Mississippi and Minnesota river valleys (corresponding to the Big Rivers Partnership project area). Other organizations and agencies are now using the MLCCS to map additional areas around the state.

Great River Greening uses the resulting landscape map in many ways at different scales. When we put the numerous land cover types into categories and view the map at a large scale, region-wide patterns emerge. Using different categories reveals different patterns useful for answering a variety of landscape-scale questions. For example, this map of the river valleys shows where development is densest and where the remaining natural vegetation is concentrated.

In another large-scale application of the land cover map, Great River Greening has developed a system to determine what native plant communities are appropriate for restoration at any given disturbed site. First we examined the existing native communities mapped using the MLCCS to see what combination of environmental factors (soil type, slope, and aspect-i.e., direction the slope faces) supports each community type. Then, for each place where the native vegetation has been removed, we looked at the same combination of environmental factors to determine the appropriate communities for restoration.

The existing land cover, as mapped by the MLCCS, also helps us select the optimal community to restore. For example, both mesic prairie and mesic oak savanna may be appropriate for a particular site, but the presence of scattered trees may make savanna a better option, while their absence may make prairie a better one.

At a medium scale, the size of a municipality, for example, a detailed land cover map can allow informed decisions about where additional land should be protected or where a restoration effort could have the greatest ecological benefit by linking separate natural areas.

Great River Greening uses the land cover map at the small scale of an individual site when we plan our projects. Management plans, sometimes looking years into the future, are based on the land cover, and the map provides a starting point when we decide what activities will occur at each part of the site. We also estimate restoration budgets from the acreage calculated from the maps.

The MLCCS was funded in part by the Minnesota Environment and Natural Resources Trust Fund, as recommended by the Legislative Commission on Minnesota Resources.