Habitat Importance for Imperiled Species is one of a suite of products from the Nature’s Network project. 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. Important Habitats are a group of critical terrestrial and aquatic habitats for imperiled species. The dataset was created by studying the overlap of 600 Species of Greatest Conservation Need (SGCN) and their documented occurrences (from tens of thousands of data points) with terrestrial and aquatic habitats mapped by The Nature Conservancy and UMASS. *NOTE - The download of this data also includes Habitat Condition for Imperiled Species and Core Habitat for Imperiled Species [links to come]
If protected, Important Habitats will help sustain a broad diversity of fish, wildlife, plants, and the key ecosystems on which they depend. These areas support high levels of biological diversity, rare species, and imperiled species, and are necessary to ensure their persistence within and in complement to terrestrial core areas. This layer was subsequently integrated with the Index of Ecological Integrity to produce Habitat Condition for Imperiled Species. That product and additional datasets that augment or complement Habitat Importance for Imperiled Species are also available in the Nature’s Network gallery on Data Basin. You may refer to the detailed technical guide to Habitat Condition for Imperiled Species for more information about the estimation and mapping of Habitat Importance.
Areas scoring highly on Habitat Importance can be viewed as habitats that are likely to support high levels of one or more imperiled terrestrial, wetland, or aquatic species, and may be particularly critical for species dependent on rare habitat classes. This map can help to focus attention on opportunities to conserve the most important habitats for imperiled species, often including localities where such habitats persist in otherwise degraded surrounding landscapes. It can also be used in combination with other tools 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.
Intended Uses
Habitat Importance for Imperiled Species is an intermediate product that is best used in conjunction with additional datasets that provide information about the integrity and resilience of habitats and the threats they are likely to face in the future. We recommend you explore this product in combination with:
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Habitat Condition for Imperiled Species, which modifies the Habitat Importance score with the Index of Ecological Integrity to estimate the condition of Important Habitats
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Core Habitats for Imperiled Species, which features the most important & intact habitats
Description and Derivation
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A more specific and localized habitat classification was created from the Northeast Terrestrial and Aquatic Habitat Classification by refining classes by distance from aquatic features and corresponding watershed (HUC6 level). In all documentation pertaining to the Nature’s Network Habitat for Imperiled Species products (Habitat Importance and Condition, and Core Habitats), “habitat class” refers to habitat classifications refined in this manner, except where specified otherwise.
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Species occurrence records from NatureServe were associated with refined habitat classes based on spatial location. Statistical corrections were used to account for unlikely or spurious intersections of species data with habitats. The relative strength of the association between each species and refined habitat class was determined by the proportion of the total number of occurrences of the species that fell in that refined habitat class.
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The patterns of species’ associations were summarized across all species, giving a single habitat importance score for each refined habitat class. The contribution of each species to the importance score was weighted by degree of species imperilment.
Habitat Importance contains a possible range of values from 0-200, where 200 represents the highest levels of co-occurrence of species and habitat dependence. Species that occur only in a few refined habitat classes result in a high relative strength of species-habitat association for those classes, and thus higher Habitat Importance scores. Strong species-habitat association creates a higher Habitat Importance score when a species is at greater risk. Finally, association with a greater number of species increases the Habitat Importance score of a habitat class. Although habitats of any level of importance above zero are shown on the map, we have identified a threshold level for the most Important Habitats as the top ⅓ of the mapped habitat importance (scores >76).
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:
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The results do not incorporate important social, economic, or feasibility factors.
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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.
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The mapping of ecosystem locations and development is known to be imperfect, which consequently affects the mapped values for 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.
