The Virginia Department of Conservation and Recreation - Division of Natural Heritage (DCR-DNH), is using species habitat modeling (SHM) to develop Predicted Suitable Habitat (PSH) maps for rare plant and animal species. These products offer a consistent tool, developed from transparent and repeatable methods, for use at local, state and regional levels, for myriad conservation and planning purposes. As of 2020, we have completed SHM and PSH products for over 179 rare species, including all federal and/or state threatened and endangered (T & E) species listed in Virginia prior to spring 2018. Furthermore, the Predicted Suitable Habitat Summary (PSHS) layer combines species- specific PSHs into a single layer, which efficiently identifies areas of greatest possible conflict/concern with rare species habitats. Some versions of the PSHS can be shared without disclosing sensitive data (Map 1). A summary of SHM products available from the Division of Natural Heritage is provided in the table below.
Product | Description | Type of Spatial Data | Uses |
Species Habitat Model (SHM) * | Map with values representing probability (values between 0 and 1) of suitable habitat for one species | Raster (grid, 30-meter resolution) | Guiding field surveys, habitat restoration |
Predicted Suitable Habitat (PSH) | Mapped extent of suitable habitat for one species, generally derived by applying a threshold to a SHM | Features (polygons) | Environmental review, habitat restoration |
Predicted Suitable Habitat Summary (PSHS) | Mapped extent of PSH for multiple species | Raster (grid, 30-meter resolution) or Features (polygons) | Environmental review, conservation and land use planning, early planning for large development projects |
*Previously referred to as Species Distribution Models (SDM)
Both the private sector and government agencies will be able to use these products in environmental review, early planning for large development projects, conservation planning, and species inventory. Different environmental review organizations may use screening data for different suites of species, various habitat datasets, and/or estimated presence/absence (e.g. at the county or watershed-level), leading to inconsistent reports on potential impacts to rare species. Development of the PSHS and its regular use by these organizations can help reduce these inconsistencies, helping to clarify and streamline the review process. With regard to conservation planning, a PSH can highlight areas where habitat for rare species might occur that traditional coarse-filter approaches might miss. PSH can also target, with subsequent field surveys to confirm suitability, habitats for protection or remediation. SHM can inform inventory (i.e. field surveys) for rare species, and therefore inform future land use decisions. Moreover, as field inventory confirms the presence or absence of species and suitable habitat, these new data will be used to refine the models, so that output maps and spatial data layers more accurately represent suitable habitat.
As with all data products, these SHM products will expire as new and better information are gathered and developed, and any model product developed by DCR-DNH expires the moment a new version is released. Our desire is to identify consistent funding to maintain a library of SHM products. We continue to expand this library to include additional rare species and natural communities as resources allow, and we continue to seek funding for this effort.
Map 1 (click to enlarge). The Potential Rare Species Richness layer categorizes 3-mile diameter hexagons into Low, Medium and High classes, based on the number of Predicted Suitable Habitat (PSH) layers that fall within the hexagon. This map is not suitable for any environmental review purposes or project planning. Higher-resolution summaries of Predicted Suitable Habitat layers are available by by subscription to the Natural Heritage Data Explorer.
For information on how to order/subscribe to SHM products, review the the Information Services Digital Data Services webpage. For other inquiries on the Species Habitat Modeling project, contact Joe Weber (Joseph.Weber@dcr.virginia.gov).