The overall level of protection for each area is summarized in these maps. We also considered protection of BioMap and Living Waters resources, natural and agricultural lands, and priority natural communities and priority habitat as indicators of quailty of protection throughout the state.

The BioMap Core Habitat layer depicts the most viable habitat for rare species and natural communities in Massachusetts. It was produced in 2001 by the Natural Heritage and Endangered Species Program (NHESP). In addition to the Cores, the BioMap Supporting Natural Landscape buffers and connects the Core Habitat polygons and identifies large, naturally vegetated blocks that are relatively free from the impact of roads and other development.

The Living Waters project completed by NHESP in 2003 depicts those areas important for conservation of aquatic resources. The Living Waters Core Habitats represent lakes, ponds, rivers, and streams that are important for the protection of freshwater biodiversity in Massachusetts. The Living Waters Critical Supporting Watersheds (CSWs) are those areas with more immediate hydrologic contributions to Living Waters Core Habitats. As such, they represent the areas with the highest potential to sustain or degrade Core Habitats.

We included the following land use types as "Natural": forested, forested wetlands nonforested wetlands, salt wetlands, powerlines, saltwater sandy beach, and brushland/successional. While powerlines are built by humans and continue to be managed, they are also host to species found only in early successional habitats. For this reason, they were included natural.

We included the following land use types as "Agricultural": cropland, pasture, cranberry bogs, orchard, and nursery.

The NHESP Natural Communities datalayer consists of polygons that represent the extent of various natural communities of biodiversity conservation interest in Massachusetts. These polygons are based on records of natural communities maintained in the NHESP database.

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).