Core Habitat for Imperiled Species, Northeast U.S

Core Habitat 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 the most intact of habitats estimated to be most important 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 Core Habitat for Imperiled Species, including Habitat Condition for Imperiled Species (the more extensive dataset from which Core Habitats for Imperiled species were selected), are also available in the Nature’s Network gallery: https://nalcc.databasin.org/galleries/8f4dfe780c444634a45ee4acc930a055. A detailed technical guide to Habitat Condition for Imperiled Species and the derivation of the Core Habitats is available at: http://www.naturesnetwork.org/wp-content/uploads/2017/04/Habitat_Condition_for_Imperiled_Species_Tech_Documentation.pdf.

Core Habitats can be viewed as the most intact areas that 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. 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.

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.

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

Core Habitat for Imperiled Species is based from the integration of 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 Condition layer to reveal the Ecological Integrity Score that contributed to an area being identified as a Core Habitat

• The Habitat Importance layer to learn the habitat class(es) within a Core Habitat and the HUC6 watershed to which it belongs.

• 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 as Core Habitats 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 the critical habitat for imperiled species that is relatively vulnerable to future development, and thus could represent priorities for land protection.

Description and Derivation

If protected, Core Habitat for Imperiled Species will sustain a broad diversity of fish, wildlife, plants, and the key ecosystems on which they depend. Core Habitat is based on the most intact of the habitats identified from Habitat Condition for Imperiled Species. That Nature’s Network product identifies areas of high importance for imperiled species in conditions ranging from intact to degraded. Important areas that scored in the top ⅓ of condition scores (>82) and were larger than a minimum size (0.18 ha) were extracted to form the Core Habitat for Imperiled Species. For more information about how habitat importance and intactness were determined, visit the Important Habitat section of the Nature’s Network website.

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 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.