Interpreting and Using Natural Heritage Inventory County Maps

The Natural Heritage Inventory (NHI) County maps are based upon data from the Wisconsin Natural Heritage Inventory. These maps are intended as a tool for the public to use in identifying areas with known occurrences of rare species (endangered, threatened and special concern) and other sensitive resources (high-quality natural communities and significant natural features) to the section level. Because these maps do not identify the specific locations of endangered resources, they are appropriate for general planning and assessment purposes only. The NHI County Maps are not an appropriate resource for screening or reviewing a proposed land management or development project for potential impacts to endangered resources. If you need more specific information about endangered resources, please request an Endangered Resources Review and/or contact the Endangered Resources Program.

Each map shows the land and water area for an entire county. The grid that overlays the county is the Public Land Survey referencing system of Townships and Sections. Each small square is approximately one mile on a side and represents a Section; larger squares represent Townships and contain 36 Sections. To the right of the map is a list of all rare species, natural communities, and natural features recorded from the county and the date each was last recorded in the NHI database.

Each color on the map represents the following information:

Light blue Squares: One or more rare aquatic species or natural communities have been documented somewhere in the section.

Green Squares: One or more rare terrestrial species or natural communities have been documented somewhere in the section.

Red Squares: Both rare aquatic and terrestrial species or natural communities have been documented somewhere in the section.

Townships with diagonal hatching: One or more rare plants, animals, natural communities, or natural features have been documented in this township (in addition to those represented within the township by light blue, green, or red squares), but a more precise location is not available.

County-level records: There are some records for plants, animals, natural communities, or natural features for which only county-level locational information is available. These elements are included in the list to the right of the NHI County Map, but are not shown on the map itself. You can find out which individual elements have only county-level locational information available by looking at the NHI County Data printout for the county. County-level records will be listed in the first section of the printout (with no associated township shown).

Black Stars: State Natural Areas. The dots do not represent area; the size of the State Natural Area may be large or small.

Thick Blue Lines: DNR basin boundaries.

Dark blue Areas: Water.

White Squares: Sections where there is no specific locational information recorded in the NHI database for a rare species or high-quality natural community. However, note that a white square does not confirm that no rare species, natural communities, and natural features are present in that section for the following reasons:

• Many areas of Wisconsin have not been inventoried for endangered resources. In particular, the vast majority of private lands in Wisconsin have not been inventoried. Also, areas surveyed for one type of resource (e.g., rare plants), often have not been surveyed for other endangered resources (e.g., rare birds).
• Rare species may occur or range over several adjacent Sections, but may have been recorded in the NHI database in only one Section.
• Rare species occurrences for which only county-level locational information is available or shared are not shown on the map.

As a result, users need to be aware that areas shown in white may still contain endangered resources. Please remember that records of endangered resources in the NHI database are only one tool to use in planning to incorporate endangered resources concerns. Planning should also consider the regional and landscape context, the quantity and quality of suitable habitat on and around the site, and other factors. In all cases, users need to take a precautionary approach: absence of evidence is not evidence of absence in the case of endangered resources, and the NHI County Data and NHI County Maps are only one tool to help gather preliminary information about endangered resources that may need to be considered in your project planning efforts.

Map dates:

Each map is dated in the lower right-hand corner to indicate when the map was produced. Since ongoing surveys continually add new information to the database, there may be additional information available. If you would like more information about endangered resources occurring in any county, please contact the Endangered Resources Program.