Maryland's Green Infrastructure Assessment Introduction
Maryland’s Green Infrastructure (GI) is our natural support system, providing ecosystem services that are necessary to humans, as well as plants and animals. As Maryland’s population increases, Green Infrastructure is being lost to development. Prior to European settlement, about 95% of Maryland’s six million acres of land was covered in forest. Today, forest cover is around 40%. In Maryland’s early post-colonial history, forest loss was due to agricultural conversion. In the early part of the 20th century, many marginal farms were abandoned and reverted back to forest. However, in the last half of the 20th century, urban development replaced an estimated 7,200 acres of forest land per year.
The scattered pattern of modern development not only consumes an extensive amount of land, it fragments the landscape, converting a once near-continuous stretch of forests and wetlands to small, isolated islands of habitat in a sea of developed land. Since a statewide comprehensive approach to address landscape fragmentation did not exist, Maryland’s Department of Natural Resources (DNR) began an effort in the late 1990’s to identify the most ecologically important lands in the State. The result of this effort is a mapped network of large blocks of intact forest and wetlands, called “hubs,” linked together by linear features such as forested stream valleys, ridgelines, or other natural areas, called “corridors.” An essential characteristic of Green Infrastructure is the interconnection of its features.
In addition to the Original Green Infrastructure, the DNR had developed three other statewide databases based upon extensive scientific work. Like the Original Green Infrastructure, each database identifies ecological attributes of land throughout the state:
The three databases are sometimes called Rare Species Habitat, Aquatic Life Hotspots and Water Quality Protection.
- The Rare Species Habitat database includes additional habitats that support rare, threatened and endangered species.
- The Aquatic Life Hotspots database adds watershed land and streams that support areas of high aquatic biodiversity.
- The Water Quality Protection database focuses on those watershed lands, such as forests, wetlands and steep slopes that are most important for improving water quality services.
How the Green Infrastructure is Being Used
The Green Infrastructure is now incorporated in the Targeting System and the Rural Legacy Grant Review System. Although the Green Infrastructure is not the only factor, it is certainly very significant in the DNR's efforts to best use its limited land protection funds.
Maryland's Green Infrastructure Assessment
Strategic Land Conservation
As of 2021, Department of Natural Resources programs compiled an enviable record in land conservation, acquiring outright 350,000 acres of natural lands and supporting conservation easements on 172,000 additional acres. Private groups like The Nature Conservancy have also protected natural areas from development. Many of these lands are incorporated in the mapped Green Infrastructure.
An important function of the Green Infrastructure Assessment is to provide maps which government agencies and private land trusts can use to help focus their efforts on strategic locations. Working together in a more coordinated way will help limited conservation dollars go further and result in more ecologically valuable purchases.
To further assist protection efforts, habitat conditions, biological data, connectivity, size and other information were assessed within each hub and corridor. These data were used to assign an ecological score for each hub and corridor to help prioritize limited conservation funding. This approach, modified for smaller areas, is now being used to assign ecological scores to parcels under consideration for protection. This information is being used to guide DNR’s conservation actions on a regular basis.
https://dnr.maryland.gov/land/Pages/Green-Infrastructure-Mapping.aspx
Maryland's Green Infrastructure Assessment
Mapping Maryland’s Green Infrastructure
The Green Infrastructure Assessment (GIA), based on principles of landscape ecology and conservation biology, identified an ecological network using satellite imagery to characterize land cover, Geographic Information System (GIS) data on road, stream, wetland and other resource features, and biological databases. The model and resulting maps were peer reviewed by scientists and local government staff. Non-natural gaps in the GI were identified as potential candidates for restoration activities.
When complete, the GIA map comprised more than 1.7 million acres in hubs and roughly 250,000 acres of corridors, totaling about 39% of the State’s land area. The network captures nearly all of Maryland’s most important ecological lands.
Data and Mapping
GI data and maps are readily available for agencies and organizations interested in conserving Maryland’s critical natural resources.
The GreenPrint Map
The GreenPrint map displays Targeted Ecological Areas (TEAs), lands and watersheds of high ecological value that have been identified as conservation priorities by the Maryland Department of Natural Resources (DNR). It also displays information about four of Maryland’s most active State operated land conservation programs: Program Open Space (POS) - Stateside, the Maryland Agricultural Land Preservation Foundation (MALPF), the Maryland Environmental Trust (MET), and the Rural Legacy Program. GreenPrint offers a way to improve how these programs work together and assists in steering POS acquisitions to the TEAs. The TEAs were developed in 2008 and then updated in 2011. This maps shows the 2011 version of the TEAs. Therefore, some older acquisitions may not appear in the TEAs, even though they were acquired using the TEAs available at that time. The maps also display other protected land data for reference.
Other Useful Resources
Why GreenPrint Lands are Important
MERLIN - make customized maps
Geospatial Data - download data for analysis and customized maps
