Priority Habitat and Estimated Habitat for Rare Species

What are Priority Habitats and Estimated Habitats in the Natural Heritage Atlas and what are they used for?

Priority Habitat is based on the known geographical extent of habitat for all state-listed rare species, both plants and animals, and is codified under MESA. Habitat alteration within Priority Habitats may result in a take of a state-listed species, and is subject to regulatory review by the Natural Heritage & Endangered Species Program. Priority Habitat maps are used for determining whether or not a proposed project must be reviewed by the NHESP for MESA compliance. See our MESA Project Review Checklist for more information about MESA filing requirements. Please note that if your project is within a Priority Habitat and is greater than two acres in size your project may be subject to MEPA (Massachusetts Environmental Policy Act) review.

Estimated Habitats are a sub-set of the Priority Habitats, and are based on the geographical extent of habitat of state-listed rare wetlands wildlife and is codified under the Wetlands Protection Act, which does not protect plants. State-listed wetland wildlife species are protected under the Massachusetts Endangered Species Act as well as the Wetlands Protection Act. Please note that if your project is within Estimated Habitat and is also subject to review as a Notice of Intent (NOI) by the local Conservation Commission, then you will also need to submit your NOI to the Natural Heritage & Endangered Species Program (NHESP) for review. Please see our Wetlands Protection Act page for more information.

It is the responsibility of the land owner or project proponent to determine if their project falls within Priority Habitat or Estimated Habitat. Certain project types are exempt from MESA review. Failure to file under MESA constitutes a violation of the Act and is subject to a fine.

How do I determine whether my property is in Priority Habitat for rare species?

Check the Natural Heritage Atlas book or CD or view Priority Habitats online.

How do I determine whether my property is in Estimated Habitat for rare species?

You can check with your local Conservation Commission to find out if you are in Estimated Habitat for rare species. The Commission has a large scale map of the town for you to view. You can also check the Natural Heritage Atlas book or CD or view Estimated Habitats online.

Where can I get Priority Habitat and Estimated Habitat maps?

Book or CD:

The Natural Heritage Atlas shows both Priority Habitats and Estimated Habitats for the entire Commonwealth, and is a tool for the public to use in the project planning process. The Atlas is available through most town libraries. A large Estimated Habitat map has been provided to each Conservation Commission showing the entire town.

Online from Mass GIS:

As GIS data layers: Priority Habitats and Estimated Habitats can be downloaded and viewed with appropritate GIS software.

Also viewable as an interactive web map.