Ecological Assessment

To determine forest areas of high ecological value, a GIS-based computer model was developed that considers both the regional and local ecological significance of the forest. The regional evaluation looks at the ecological importance of large forest patches relative to other forest patches within the same physiographic region. Variables relevant at local scales help to identify conservation values at or in close proximity to a specific parcel.

The SFLA ecological assessment builds on several existing DNR landscape assessment initiatives, including:

• the Green Infrastructure Assessment, which integrates GIS and principles of landscape ecology to help identify a statewide network of ecologically important hubs and corridors, and



• the watershed framework employed in Maryland’s Unified Watershed Assessment, which incorporates watershed based indicators in an effort to better understand Maryland’s ecological resources and the landscape stresses which confront them.

The data that have been assembled for the ecological model were selected based on their utility in measuring ecological values important to land conservation programs. Specifically, principles of landscape ecology and conservation biology have been interpreted and represented by GIS data layers. Each data set was scored and weighted to represent the importance of that factor in assigning an overall ecological score. These scores were sorted into High, Medium, and Low rankings and mapped both statewide and for each of the 23 counties.

The ecological model gives priority or greater weight to large forest blocks, particularly:

• forest patches with a greater proportion of “interior” conditions
• intact blocks of forest (as opposed to patches containing substantial nonforest “gaps”)
• patches with a diversity of habitat types
• patches that provide stream or erodible soils protection
• patches that are in close proximity to other forest blocks (as opposed to isolated patches with substantial interpatch distance)

The ecological model also favors forested corridors that:

• are short as opposed to long,
• are wide as opposed to narrow,
• contain or have the potential to contain interior forest conditions,
• are intact as opposed to fragmented;



• link forest blocks ranking high as opposed to those that rank low,
• link similar as opposed to dissimilar ecotypes,
• have few or no road crossings,
• protect and link riparian systems, and
• connect with large forest blocks.

In addition to the composite ecological model, SFLA has resulted in the creation of a variety of ecological data sets and indicators for Maryland’s forests. Examples include:

• Percent of each watershed that is forested
• Forests providing habitat for sensitive species
• Forest fragmentation patterns (not available)
• High quality habitat for forest interior-dwelling species (FIDS)

For a complete list of ecological indicators, please select Data and Indicators.