For several years, the Commonwealth of Massachusetts has been encouraging its cities and towns to participate in conservation planning for biodiversity, and community planning for Smart Growth by providing data and economic incentives. Besides providing maps showing each community’s current land use and what it would look like at projected full “build-out”, the state has also been gathering and creating environmental data that can help communities and conservation groups protect their valuable natural resources. Most of this data is available free to interested parties by download over the Internet.

MassGIS, the Commonwealth of Massachusetts’ Office of Geographic & Environmental Information, is the source for this data. As the official state agency for GIS (Geographic Information Systems) it creates, collects, stores, and distributes digital geographic and environmental data for Massachusetts from the various state and federal agencies. Through MassGIS, Massachusetts has created a comprehensive, statewide database of spatial information for environmental planning and management. Examples of this information include statewide land use and zoning, surficial geology, hydrography, wetlands, contours, certified and potential vernal pools, and protected and recreational open space parcels. All of this data and more is free to download off the MassGIS website (http://www.state.ma.us/mgis/massgis.htm), or to view online.

Creating the Priority Natural Vegetation Communities Datalayer

As part of the effort to provide useful environmental information for conservation planning, MassGIS is creating the PRIORITY NATURAL VEGETATION COMMUNITIES datalayer. This data consists of detailed mapping of the eight natural community systems identified by the Massachusetts Natural Heritage & Endangered Species Program (NHESP) as most critical to the conservation of the Commonwealth’s biological diversity. Conservation of these eight community systems would collectively protect 70% of the state-listed rare species, and many of the common ones (Barbour et al. 1998). The eight Priority Natural Communities Systems are: Coastal, Coastal Plain Ponds, Acidic Peatlands, Riverine, Maritime Sandplain, Pine Barrens, Vernal Pools, and Calcareous.

Figure 2: Color infrared aerial photo of Cohasset Harbor, Scituate

Brief descriptions of these systems can be found at (http://www.state.ma.us/mgis/natveg.htm).Descriptions of the individual community types within the systems, such as maritime shrubland or brackish tidal marsh within the Coastal system, are taken from Swain & Kearsley’s “Classification of the Natural Communities of Massachusetts” (July 2000). This publication is available through NHESP.

The Priority Natural Communities data is created primarily through aerial photo interpretation of recent large-scale (1:12,000) color infrared photographs, with limited field reconnaissance. Information from other agencies and local experts is used as much as possible to improve the accuracy of the data. Digitizing is done in Arcview 3.2 with the Optem digital transfer stereoscope. This equipment allows the user to view the aerial photos in stereo, and digitize the linework simultaneously on the computer screen.

Practical uses for the Priority Natural Communities data

The Priority Natural Communities data identifies in detail the distribution, size, and location of the Priority Community types. With the help of GIS, this data is usable at a regional to local scale. At a regional scale, it shows landscape patterns of distribution, and relative rarity of types.

Figure 3: Regional view of Priority Natural Communities in southeastern Massachusetts

Figure 4: Ridgetop pitch pine community in lynn

Figure 3 shows the distribution in southeastern Massachusetts of Atlantic white cedar swamps, bogs

and fens in red; pitch pine barrens in dark green; and coastal plain ponds in dark blue. Such data is useful for regional conservation planning by land trusts or environmental agencies, and for communities interested in knowing how they fit into the bigger picture.

At the local level, the Priority Natural Communities data provides specific information on the location and size of priority community types.

Figure 4 shows ridgetop pitch pine, part of the Pine Barrens community, near a residential development in Lynn. With the color orthophoto in the background, interested residents can find any of the priority sites in their town. This community level data would be useful for open space and community development plans. It might also be useful in support of open space funding applications, where areas with assemblages of priority community types might be considered a higher priority for conservation.

The Priority Natural Communities data can be used with other GIS datalayers to provide improved information for conservation and community planning. For instance, Figure 5 shows a portion of the town of Gloucester, with the priority natural communities in yellow (maritime grassland), dark blue (coastal), turquoise (acidic peatland), and the protected open space & recreational land parcels in brown. This open space data shows public and private conservation lands, and outdoor recreation facilities. On this map, most of the open space parcels on the left are town or private conservation land, and the golf course on the right is private recreational land.

Together with the Priority Natural Communities data, one can create a “mini-gap” analysis, identifying potential priority habitat that is not protected. In this part of Gloucester, the shrub and graminoid fen in the middle is mostly unprotected, while the sandplain grassland is on protected land. The next step would be to visit those sites identified as priority communities on the map in order to evaluate the quality of each site. Aerial photo-interpretation can identify vegetation, but cannot assess the quality of a site for biodiversity, or the actual presence of rare plants and animals. As with all remote sensing products, one needs to field check the information before making any decisions.

Orthophotos and other free datalayers from MassGIS

Figure 5: orthophoto with fen in middle, golf course on right. Priority Natural Communities and Protected Open space in East Gloucester

The background in Figure 5 is a digital, natural color orthophoto. Orthophotos are aerial photographs that have been rectified to remove distortion, so the scale is consistent and accurate. Distances and areas can be accurately measured on these orthophotos, making them excellent base maps for any kind of conservation mapping. These incredible images were flown in April 2001. Color orthophotos like Figure 5 are now available from MassGIS for the entire Commonwealth of Massachusetts.

MassGIS offers other free datalayers that are helpful for conservation planning. These include the DEP (Department of Environmental Protection) 1:5000 scale wetlands, certified and potential vernal pools, areas of critical environmental concern, aquifers, outstanding resource waters, NHESP priority habitat for rare species, 30-foot contours, soils, EPA ecoregions, and the NHESP Biomap core and supporting natural landscapes. There are also datalayers showing State Register of Historic Places districts and sites, regional bike trails, shellfish stations, water quality monitoring stations, watersheds, major streams, accurate roads, and census information. All of this data gives users a good start in their conservation planning, supplying them with basic information that can then be improved upon with local knowledge.

References:

Barbour, H. T., .T. Simmons, P. Swain. and H. Woolsey. 1998. Our Irreplaceable Heritage: Protecting Biodiversity in Massachusetts. Natural Heritage & Endangered Species Program, Massachusetts Division of Fisheries and Wildlife and the Massachusetts Chapter of The Nature Conservancy. Boston, MA.

Swain, P.C., and J. B. Kearsley. July 2000. Classification of the Natural Communities of Massachusetts. Natural Heritage & Endangered Species Program, MA Division of Fisheries and Wildlife. Westborough, MA.

Note: The author is employed at MassGIS, in the Executive Office of Environmental Affairs. Her views are her own, and do not necessarily represent those of the agency.