OVERVIEW

The Priority Habitats of Rare Species datalayer contains polygons representing the geographic extent of Habitat of state-listed rare species in Massachusetts based on observations documented within the last 25 years in the database of the Natural Heritage & Endangered Species Program (NHESP). Priority Habitats are the filing trigger for proponents, municipalities, and other stakeholders for determining whether or not a proposed project must be reviewed by the NHESP for compliance with the Massachusetts Endangered Species Act (MESA). The Priority Habitats presented here are those published in the 12th Edition of the Massachusetts Natural Heritage Atlas, and are effective beginning October 1, 2006. Minor amendments were made to the Priority Habitats and Estimated Habitats in the towns of Lancaster and Truro on December 1, 2006 and in Acton, Concord, Lunenburg, Mattapoisett, Maynard and Tewksbury on October 1, 2007.

In July, 2005 major revisions were made to the MESA regulations (321 CMR 10.00). These revised regulations clarify filing requirements and procedures, set timelines for agency response, establish filing fees, expand and add definitions, and formalize the appeal process for agency decisions.

If your project or activity falls within Priority Habitat and does not meet a MESA filing exemption (321 CMR 10.14), then you must file directly with the NHESP pursuant to MESA. For more information, please see the Regulatory Review section of the NHESP website.

The Priority Habitats of Rare Species datalayer is stored in ArcSDE as PRIHAB_POLY. (The previous version of this layer was named PHAB2005_POLY).

Priority Habitats were digitized by NHESP scientists from documented observations of rare species and are based on such factors as species movements and habitat requirements. The polygons were heads-up digitized in ArcView 3x, at a scale of 1:25,000, and referenced to MassGIS’s 2001 Color Orthophotos.

The layer's polygon attribute table has the following  attributes:

PRIHAB_ID		A unique identifier for each polygon. This number may be used to identify a Priority Habitat polygon when contacting the NHESP.
VERSION		Indicates the effective date of the Priority Habitat polygons, as well as the edition of the Natural Heritage Atlas in which they were presented.

Priority Habitats should be displayed as follows:

• At 1:25,000 scale or smaller (e.g. 1:35,000), as this is the scale at which the polygons were delineated.
• Against MassGIS’s 2001 Color Orthophotos as a reference layer.
• Using the “NHESP Priority Habitats for Rare Species” legend, which MUST accompany this datalayer on ALL maps.
• NOTE: the following 12 towns contain Priority Habitats that are less than 1 acre in size. To effectively display these small areas, the line thickness of the polygon may need to be increased:

Barnstable		Fairhaven		Sandwich
Chicopee		Great Barrington		Scituate
Dartmouth		Middleborough		Sheffield
Duxbury		Royalston		Williamstown

Occurrence records are continually being added and modified in the NHESP database. These changes are incorporated into the Priority Habitats of Rare Species datalayer every two years, for inclusion in the Natural Heritage Atlas.

Questions about this datalayer should be directed to NHESP at 508-389-6375.

Also see these layers:

• NHESP Estimated Habitats of Rare Wildlife
• NHESP Certified Vernal Pools
• NHESP Potential Vernal Pools

Last Updated 10/24/2007
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