Habitat Condition for Imperiled Species is one of a suite of products from the Nature’s Network project (naturesnetwork.org). Nature’s Network is a collaborative effort to identify shared priorities for conservation in the Northeast, considering the value of fish and wildlife species and the natural areas they inhabit. This product represents a regional network of habitats critical for sustaining populations of imperiled species, currently based on over 600 Species of Greatest Conservation Need (SGCN).

A number of additional datasets that augment or complement Habitat Condition for Imperiled Species, including Core Habitat for Imperiled Species, are also available in the Nature’s Network gallery. A detailed technical guide to Habitat Condition for Imperiled Species is available at: http://www.naturesnetwork.org/wp-content/uploads/2017/04/Habitat_Condition_for_Imperiled_Species_Tech_Documentation.pdf.

Areas scoring highly on Habitat Condition can be viewed as areas that are relatively intact which contain habitats likely to support high levels of biological diversity, rare species, and/or imperiled species in any given landscape. This map can help to focus attention on opportunities to conserve the most intact habitats for imperiled species, often including localities where such habitats persist in otherwise degraded surrounding landscapes. It can also be used as a tool for planning the recovery of populations and restoration of their habitats where habitat importance for imperiled species is high but ecological integrity is poor. The data may also be considered as the basis for multi-species habitat conservation to secure a broad suite of imperiled species–before regulatory action is needed.

Generally speaking, this analysis indicates that riparian areas, including associated sandplains and other unique lowland habitats, are the most critical for the imperiled species assessed.

Intended Uses

• Protect biodiversity by understanding the ecological importance of individual areas

• Identify the most intact habitats for imperiled species, often including localities where such habitats persist in otherwise degraded surrounding landscapes.

• Identify key habitats for restoration to recover populations of imperiled species

• Serve as a fine-filter complement to the coarse-filter perspective of the terrestrial and aquatic core areas.

If you are especially interested in the most intact habitat for imperiled species, you may wish to explore the dataset Core Habitat for Imperiled Species, Northeast U.S., which consists of the highest ⅓ of Habitat Condition based on ecological integrity scores.

Habitat Condition for Imperiled Species integrates species occurrence data classified by habitat type and measures of intactness and resiliency. Other sources of information that identify opportunities and risks of change in these areas would be particularly complementary in directing action. You might explore this product in combination with:

• The Habitat Importance layer to learn the habitat class and distance to water of an intact habitat, as well as the HUC6 watershed in which it occurs

• The Terrestrial Core-connector Network to identify “corridors” that could facilitate the movement of plants and animals and increase the resiliency of the imperiled species habitat to uncertain land use and climate change

• The Aquatic Core Networks and Terrestrial Core-connector Networks to prioritize intact and resilient places also identified by Habitat Condition for Imperiled Species

• The Secured Lands (Eastern U.S.) layer to identify the habitats that remain unsecured from development, and thus could represent priorities for land protection

• The Probability of Development layers (2030 and 2080) and regional vulnerability layers to identify habitat for imperiled species that is relatively vulnerable to future development, and thus could represent priorities for land protection

Description and Derivation

A two step process was used in the creation of Habitat Condition for Imperiled Species. Initially, the habitats important for SGCN were mapped. The resulting Habitat Importance for Imperiled Species (available as a separate dataset) identifies areas which support high levels of biological diversity, rare species, and/or imperiled species, and are necessary to ensure their persistence. To identify habitats most likely to support SGCN over the long term, areas in the top ⅓ of Habitat Importance scores were then screened for habitat condition using the Index of Ecological Integrity. All habitats shown in the Habitat Condition for Imperiled Species layer are “important,” but only the locations scoring highly in the data layer can be considered both “important” and “intact.” If protected, these areas will sustain a broad diversity of fish, wildlife, plants, and the key ecosystems on which they depend.

Habitat Condition scores range from 0-200, where 200 represents the product of the maximum Important Habitat Score (200) and the maximum Index of Ecological Integrity Score (1). We cautiously recommendinterpreting the top ⅓ of Habitat Condition as intact, the middle ⅓ as being moderately intact and the bottom ⅓ as being degraded and probably in need of restoration. The top, middle, and bottom third of the Habitat Condition layer are labelled “Protect”, “Buffer”, and “Restore” in the included layer file. The labels are not a formal prescription for action, they are only meant to help interpret the condition of the habitats.

Known Issues and Uncertainties

As with any project carried out across such a large area, this product is subject to limitations. The results by themselves are not a prescription for on-the-ground action; users are encouraged to verify, with field visits and site-specific knowledge, the value of any areas identified in the project. Known issues and uncertainties include the following:

• The results do not incorporate important social, economic, or feasibility factors.

• Users are cautioned against using the data on too small an area (for example, a small parcel of land), as the data may not be sufficiently accurate at that level of resolution.

• The identification of areas as providing habitat for imperiled species does not necessarily mean that imperiled species are actually present in those areas.

• The labels of “Protect”/intact, “Buffer”/moderately intact, and “Restore”/degraded are only a cautious recommendation. The labels are not a formal prescription for action, they are only meant help interpret the condition of the habitats.

• The mapping of ecosystem locations and development is known to be imperfect, which consequently affects the mapped values for ecosystem integrity and species habitat. While the ecosystem mapping is anticipated to correctly reflect broad patterns of ecosystem occurrence, errors in classification and placement do occur, as with any regional GIS data. In addition, errors in mapping and alignment of development, roads, traffic rates, and a number of other data layers can affect the model results.

Please see the Technical Documentation for additional discussion of issues and limitations, including known limitations of Natural Heritage program mapping of imperiled species.