Digital Data and Products


The Maryland Natural Heritage Program maintains the largest, most comprehensive inventory of the state’s rare species and natural communities. These rare resources have been documented at nearly 10,000 distinct locations over the last 30 years. Data have been compiled from published and unpublished literature, herbaria and museum collections, interviews with scientists and local accomplished naturalists, and surveys conducted by Department of Natural Resources biologists and contractors.

These data are stored and analyzed using an international standardized information management methodology practiced by the Network of Natural Heritage Programs and Conservation Data Centres, collectively known as NatureServe, (Exits the Department of Natural Resources site). NatureServe has member programs in all 50 states, as well as many countries and provinces throughout the western hemisphere. This methodology is supported by Biotics, a standard Geographic Information Software program developed by NatureServe. Because all members of the network use standardized data collection and storage methods, information maintained by the Maryland Natural Heritage Program is an integral part of regional, national, and international planning efforts to preserve natural diversity.

The information contained within Biotics is considered “raw” data. These data have been reviewed and analyzed by Program biologists and have been reformatted into products that are more useful for conservation purposes, such as the review of development projects, review and prioritization of potential acquisition and easement projects, and local government planning and zoning requirements. Our publicly available digital data products are listed below. These data can be downloaded from Department of Natural Resources Geospatial Data Center.

Biodiversity Conservation Network (BioNet)

BioNet is a GIS data layer that prioritizes areas important for saving Maryland’s vanishing biodiversity. It was developed primarily to aid the Department of Natural Resources, other government agencies, and non-profit conservation organizations determine where conservation efforts are most needed.  This layer can be used to help focus a wide array of conservation activities, such as land acquisition and easements, land planning, and management actions.  Prioritization criteria are based on the relative rarity and conservation value of the species and habitats present: the most critically significant areas contain the rarest habitats and species, as well as the largest concentrations of these, statewide.  If you are interested in learning more about the BioNet data layer, please read the Biodiversity Conservation Network Fact Sheet.

Sensitive Species Project Review Areas (SSPRA)

SSPRA is a GIS data layer developed to aid the Department of Natural Resources, other state agencies, and county planning offices in reviewing projects for potential impacts to rare species and certain other species groups which are regulated in Maryland. SSPRA was developed by combining nine separate data layers to form a "one-stop shopping" polygon map for species which are considered rare or sensitive to development pressures. To learn more about the SSPRA data layer, please read the Sensitive Species Project Review Areas (SSPRA) Fact Sheet.

Natural Heritage Areas (NHA)

Thirty-two Natural Heritage Areas in Maryland are listed in the state's Threatened and Endangered Species regulations (COMAR 08.03.08). Most of these are located in the Chesapeake Bay Critical Area and are provided protection through the State’s Critical Area Law. The remainder are found on department lands throughout the state. By definition, a Natural Heritage Area must (1) Contain one or more threatened or endangered species or wildlife species in need of conservation; (2) Be a unique blend of geological, hydrological, climatalogical or biological features; and (3) Be considered to be among the best Statewide examples of its kind.

Wetlands of Special State Concern (WSSC)

In Maryland, certain wetlands with rare, threatened, endangered species or unique habitat receive special attention. The Code of Maryland Regulations (COMAR) Title 26, Subtitle 23, Chapter 06, Sections 01 & 02 identifies these Wetlands of Special State Concern (WSSC) and affords them certain protections including a 100 foot buffer from development. Using technical expertise and information from the Wildlife and Heritage Service, the Maryland Department of the Environment is responsible for identifying and regulating these wetlands.

Potential Habitat for Forest Interior Dwelling Species (FIDS)

Certain animals, called Forest Interior Dwelling Species (FIDS), are known to require habitat conditions in the interior of large forests for optimal reproduction and survival. The most researched and best known FIDS are a group of breeding birds that include scarlet tanager, American redstart, hooded warbler, and barred owl, among others. FIDS Habitat is provided protection under the Critical Areas Law in Maryland. It has been defined as a forest tract that meets either of the following conditions: a. Greater than 50 acres in size and containing at least 10 acres of forest interior habitat (forest greater than 300 feet from the nearest forest edge); or b. Riparian forests that are, on average, at least 300 feet in total width and greater than 50 acres in total forest area. The stream within the riparian forest must be perennial, as indicated on the most recent U.S. Geological Survey 7.5 minute topographic maps or as determined by a site visit. A subset of this habitat, called High Quality FIDS Habitat, has been further defined. The detailed definition can be found in the FIDS guidance paper for the Critical Area or in the metadata for the GIS data product. The GIS data product contains only the results of a model depicting where potential FIDS habitat might occur based on certain defined criteria. These polygons have NOT been field tested or field verified for actual FIDS presence.

For more information, please contact:

Maryland Department of Natural Resources
Wildlife and Heritage Service
Tawes State Office Building, E-1
Annapolis MD 21401
Toll-free in Maryland: 1-877-620-8DNR, Ext. 8540