Nature’s Network Conservation Design, Northeast U.S.

Nature’s Network Conservation Design depicts an interconnected network of lands and waters that, if protected, will support a diversity of fish, wildlife, and natural resources that the people of the Northeast and Mid-Atlantic region depend upon. This map serves as the “cover page” for the Nature’s Network (naturesnetwork.org) suite of products: it outlines some of the most important natural areas in the region and provides an entry point to learn more about the information used to identify them. The Conservation Design represents a combination of three Nature’s Network products: 1) the terrestrial core-connector network, 2) aquatic core areas, and 3) core habitat for imperiled species.

The Terrestrial Core-connector Network is made up of  two components: 1) terrestrial and wetland core areas, and 2) connectors. Terrestrial and wetland core areas are intact, well-connected places that have the potential to support wildlife and plants that occur in terrestrial settings (such as upland forests) or in wetlands (such as marshes). These core areas contain important or unique features, including intact, resilient examples of every major ecosystem type in the Northeast and Mid-Atlantic. Core areas contain widespread ecosystems (such as hardwood forests), rare natural communities (such as bogs), and important habitat for a variety of fish, wildlife, and plants. By design, they encompass approximately 25% of the landscape of the region. Core areas are linked together by a network of connectors. If protected, the connectors will foster the movement of animals and plants between core areas and across the landscape into the future. An additional feature of the Terrestrial Core-connector Network is a separately derived network of Grassland Bird Core Areas, the top 10% of which are incorporated into Nature’s Network Conservation Design. Find more information and additional datasets that augment or complement the Terrestrial Core-connector Network here: http://www.naturesnetwork.org/data-tools/terrestrial-and-wetland-core-networks/

Aquatic core areas are intact, well-connected stream reaches, lakes, and ponds in the Northeast and Mid-Atlantic region that, if protected as part of stream networks and watersheds, will support a broad diversity of aquatic species and the ecosystems on which they depend. They serve as the aquatic counterpart to terrestrial and wetland core areas. They feature intact, resilient examples of every major aquatic ecosystem in the region and also are designed to incorporate habitat for important species such as brook trout, American shad and Atlantic salmon. By design, aquatic core areas encompass approximately 30% of both the region’s river and stream miles (lotic core areas) and the region’s area of lakes and ponds (lentic core areas).  Find more information and additional datasets that augment or complement the aquatic core areas here: http://www.naturesnetwork.org/data-tools/aquatic-core-networks/

Core Habitat for Imperiled Species can be viewed as relatively intact areas that contain habitats likely to support high levels of imperiled terrestrial and aquatic species. This product represents a regional network of habitats critical for sustaining populations of imperiled species, based on over 600 Species of Greatest Conservation Need (SGCN). Core habitat for imperiled species is intended to complement aquatic core areas and terrestrial and wetland core areas by highlighting ecosystem (habitat) types where they are closely associated with high numbers of imperiled species. By design, core habitats encompass approximately the top 10% of the natural landscapes estimated to be intact and most important for sustaining imperiled species. Find more information and additional datasets that augment or complement Core Habitat for Imperiled Species here: http://www.naturesnetwork.org/data-tools/habitat/

Intended Uses

Nature’s Network Conservation Design, and the broader suite of products and tools of which it is part, offer voluntary guidance to:

• Protect the irreplaceable - identify the best places to start for strategic conservation: those which are intact and resilient places that encompass a diversity of lands and waters, and are important habitat for key species. These are the places we cannot afford to lose to ensure a sustainable future for human and natural communities in the Northeast.

• Look ahead to make better decisions today - identify places with potential for resilience to future environmental changes.

• Maximize limited resources - apply science-based guidance for identifying the highest conservation priorities in the region, which equips partners to use limited resources more effectively.

• Reinforce local priorities with regional perspective - look at how local resources and conservation efforts fit into the bigger landscape picture, which can help boost priorities by demonstrating their significance on a regional scale.

• Find opportunities to work together - conserving fish, wildlife and natural benefits in the face of increasing threats is beyond the scope of any single organization. Using these shared regional data, partners can look across political boundaries for opportunities to work together at scales that matter for people and wildlife.

Nature’s Network Conservation Design brings together three of a suite of products from Nature’s Network, each of which is itself the integration of a set of foundational datasets. Thus, the Core Design is representative of the vision of Nature’s Network, while simultaneously being a canvas on which to elaborate conservation plans by combining it with auxiliary products and other sources of information. Some additional products you may wish to explore are:

• The set of Road-bounded Natural Blocks, which are natural areas that surround and help support the integrity of terrestrial and wetland core areas, as well as providing practical units for protection.

• Aquatic Buffers, which, together with the aquatic core areas, constitute the Aquatic Core Networks. These are upslope and upstream areas that have a strong influence on the integrity of the aquatic cores.

• Habitat Condition for Imperiled Species, the more extensive dataset on which Core Habitats for Imperiled species is based. This product depicts the ecological condition of ecosystem types most important for imperiled species.

• Marsh Migration Zones, to identify zones where tidal marshes could move as sea level rises.

• Regional Flow, Anthropogenic Resistance (Simplified Categories), to view patterns of landscape connectivity independent of terrestrial core areas.

Description and Derivation

Nature’s Network Conservation Design is based on GIS analyses designed to assess the physical and biological value of resources across the Northeast and Mid-Atlantic, and to identify the most important places and connections for them. It is a combination of three Nature’s Network products: 1) the terrestrial core-connector network, 2) aquatic core areas, and 3) core habitat for imperiled species. Detailed technical guides to complete versions of these products used in Nature’s Network Conservation Design are available:

The Terrestrial Core-connector Network: http://jamba.provost.ads.umass.edu/web/lcc/DSL_documentation_tCoreNet.pdf

Aquatic Core Network: http://jamba.provost.ads.umass.edu/web/lcc/DSL_documentation_aCores.pdf

Habitat Condition for Imperiled Species: http://www.naturesnetwork.org/wp-content/uploads/2017/04/Habitat_Condition_for_Imperiled_Species_Tech_Documentation.pdf

Nature’s Network Conservation Design was derived as follows:

1) A raster version of the following polygon datasets was acquired or derived:
    a) Lotic Core Areas, Stratified by Watershed, Northeast U.S. (Note that in the version used for the combined product, core areas span the full width of rivers, whereas the polygon (line) version only encompasses the centerline of the streams and rivers.)
    b) Lentic Core Areas, Stratified by Watershed, Northeast U.S.
    c) Terrestrial Core-Connector Network, Northeast U.S.
    d) Grassland bird cores – a version containing the top 10% of grassland bird habitat, based on landscape capability for Eastern Meadowlark, a species representative of the grassland bird community.
    e) Core Habitat for Imperiled Species, Northeast U.S.

2) Lotic and lentic core areas were combined into a single aquatic core area dataset where core areas received a single value (including those limited areas where lentic and lotic core areas overlapped).

3) Terrestrial and wetland cores were combined with grassland bird cores into a single terrestrial core area dataset.

4) Aquatic cores, terrestrial cores, core habitat for imperiled species, and terrestrial connectors were combined (using ArcGIS Map Algebra) such that all possible combinations received a unique value (e.g., where aquatic cores overlapped with core habitat for imperiled species), except that connectors received a value in the final product only where they did not overlap any of the core areas. In other words, core areas of any type take precedence over connectors in the final product.

Known Issues and Uncertainties

As with any project carried out across such a large area, Nature’s Network Conservation Design is subject to limitations. The results by themselves are not a prescription for on-the-ground action; users are encouraged to verify, with field visits and site-specific knowledge, the value of any areas identified in the project. Known issues and uncertainties include the following (please refer to the QuickStart guides described previously for additional component-specific issues):

• Users are cautioned against using the data on too small an area (for example, a small parcel of land), as the data may not be sufficiently accurate at that level of resolution.

• While the ecosystem mapping is anticipated to correctly reflect broad patterns of ecosystem occurrence, errors in classification and placement do occur, as with any regional GIS data. In addition, errors in mapping and alignment of development, roads, traffic rates, and a number of other data layers can affect the model results.

• This product does not provide information about the properties of individual core areas. That information is available in the component products: the terrestrial core-connector network and the aquatic core areas.

• At this time, Nature’s Network does not assess underwater, benthic, offshore, or marine habitats. Estuaries and marine areas are, for the most part, not included in the conservation design, although there are some exceptions. Exceptions include cases where habitats for species that use estuaries (e.g., American black duck and diamond-backed terrapin) have been incorporated into terrestrial and wetland core areas.

• The identification of areas as providing habitat for imperiled species does not necessarily mean that imperiled species are actually present in those areas.