Terrestrial Resilience Core Concepts

These core concepts are generalized for the completed region. For specific methods see links to individual chapters.

Resilient Site: An area of land with sufficient variability and microclimate options to enable species and ecosystems to persist in the face of climate change and which will maintain this ability over time.

Geophysical Settings: Broadly defined landscape types that contain a variety of plants, animals and natural habitats that occur in similar geologic environment (e.g. similar bedrock, soils and elevation zone). If conservation succeeds, each geophysical setting will support species and communities that thrive in conditions defined by its physical properties, although the species in the future may differ from those currently present. In this study, we defined geophysical settings by mapping and classifying combinations of geology and elevation. Read the Eastern Resilience Methods or the Great Lakes and Tallgrass Prairie Methods.

Natural Stronghold: a resilient site that currently supports exemplary habitats, wildlife, or rare species, and may provide refuge for these elements as the climate changes.

Two Example Settings:

Resilience Score: A site’s Resilience Score estimates its capacity to maintain species diversity and ecological function as the climate changes. The score is relative to all other sites with the same geophysical setting and is described on a relative basis as above or below average. For example, granite mountains were compared with other granite mountains, and coastal plain sands were compared with other coastal plain sands. Our goal was to identify the places most resilient to climate change for each type of setting. A site’s final resilience score was determined by evaluating physical characteristics that foster resilience, particularly the site’s landscape diversity and local connectedness.

Characteristics that Foster Resilience: A resilient site is one that offers many options to species and ecosystems. Such options, include topographic and elevation diversity that provide a range of habitat types and microclimates (landscape diversity), and minimal barriers that restrict adaptive movement of species or ecosystems (local connectedness).

Landscape Diversity: Refers to the microhabitats and climatic gradients available in one’s immediate neighborhood. Topographic diversity buffers against climatic effects because the persistence of species in an area increases in landscapes with a wide variety of microclimates. In this study, we measure microclimates by counting the variety of landforms, measuring elevation range, and the density and configuration of wetlands in a 100 acre neighborhood around every point on the landscape. Read the Eastern Resilience Methods or the Great Lakes and Tallgrass Prairie Methods.

Local Connectedness: refers to the number of barriers and the degree of fragmentation within a landscape. A highly connected landscape promotes resilience by allowing species to move around the landscape and find suitable microclimates where they can persist. In this study, we measure local connectedness by measuring the amount of natural land cover and configuration of human-created barriers like major roads, developments, and agricultural land. Read the Eastern Resilience Methods or the Great Lakes and Tallgrass Prairie Methods.

Riparian Climate Corridors: Riparian areas are the floodplains and zones along water bodies that serve as interfaces between terrestrial and aquatic ecosystems. With respect to climate change, riparian areas feature micro-climate refugia that are significantly cooler and more humid than immediately surrounding areas. Our objective was to identify intact riparian floodplain areas that serve as natural corridors to facilitate movement of plants and wildlife linearly, taking advantage of the cooler moister environment within these areas.

  1. High Flow Riparian Corridors, largely within resilient land: These riparian corridors have high regional terrestrial permeability flow and have >75% of their land area within resilient land. They have a minimum size of 1,000 acres and are considered highly intact and resilient.
  2. High Flow Riparian Corridors, largely outside resilient land: These riparian corridors have high regional terrestrial permeability flow, but are <75% within resilient land. They have a minimum size of 5,000 acres and touch at least 3 prioritized diversity features. They are considered more vulnerable given a significant portion of their area falls on non-resilient land.


Resilient and Connected Networks Core Concepts

These core concepts are generalized for the completed region. For specific methods see links to individual chapters.

Resilient and Connected Networks:

Movement Areas:

Regional Flows: A continuous wall-to-wall model of landscape permeability based on anthropogenic resistance. Brown indicates areas with low permeability where movement is blocked. Medium blue indicates areas of moderate flow; often highly natural settings were species movements are diffuse. Dark blue indicates areas of concentrated flow where movements will accumulate or be channeled. Read the detailed methods.

Regional Flow Classified: A classified map of Regional Flow patterns that revels key patterns in current flow. Each flow type has a different suggested conservation strategy.

Read the detailed methods.

Riparian Climate Corridors: Riparian areas are the floodplains and zones along water bodies that serve as interfaces between terrestrial and aquatic ecosystems. With respect to climate change, riparian areas feature micro-climate refugia that are significantly cooler and more humid than immediately surrounding areas. Our objective was to identify intact riparian floodplain areas that serve as natural corridors to facilitate movement of plants and wildlife linearly, taking advantage of the cooler moister environment within these areas.

Read the detailed methods.



Resilient Coastal Sites Core Concepts

Site Resilience is the ability of a site to support biological diversity and ecological functions even as it changes in response to climate change and sea level rise (Anderson et al. 2016). We expect coastal sites to change dramatically over the next century. Many of our existing marshes are already converting to open water and new tidal habitats are forming or migrating into adjacent low lands where suitable space is available to accommodate them. Identifying places where conservation can succeed, and restoration actions could help sites adapt to change, is a necessary step in sustaining the diversity and functions of coastal habitats.

To identify resilient sites, we evaluated over 10,000 tidal complexes (interconnected tidal habitats such as salt marsh, tidal flat, and brackish marsh), the adjacent migration space (suitable low-lying areas that could accommodate future tidal habitats), and the buffer area (natural and agricultural lands surrounding a site).

For each site, we assessed its physical properties for characteristics that would allow for habitat migration: size of migration space, number of tidal zones, amount of shared edge, etc. We also assessed condition characteristics that would facilitate migration: absence of barriers, adequate sediment supply, suitable water quality, etc. We combined the normalized scores for the physical and condition factors to calculate an index of site resilience.

To account for uncertainty, we calculated the resilience scores for six sea level rise scenarios (1 to 6 ft., in 1-ft. increments), assessed the trend in migration space size over time, and evaluated the physical and condition characteristics of the surrounding buffer area. The final scores are given for the 6’ sea level rise scenario as these are the most robust sites for long-term resilience.

Final scores indicate the relative resilience of the site in comparison to all other sites within its respective Coastal Shoreline Region. Scores indicate the standard deviations above or below the average score (0) for the Shoreline Region. For example, a score of 1.5 SD means the site scores 1.5 standard deviations above the average score for the Shoreline Region. In other words, the site scores higher than 69% of the other sites in its Shoreline Region. Coastal Shoreline Regions were: Maine Drowned River Valleys, Southern New England Coastal Embayments, Northeast River-Dominated, Chesapeake Bay River-Dominated, and Mid-Atlantic Coastal Lagoons.

Migration space is the area of adjacent low-lying land that is potentially suitable for supporting tidal habitats in the future as sea levels rise, and into which the current habitats could migrate. The left image illustrates how current tidal marsh is expected to move into its migration space, while the existing marsh is lost to inundation. The image on the right shows the current marsh and migration space (orange) for a section of Great Marsh, MA.

To learn more about the methods and results, access the final report here.

Citation:Anderson, M.G., Barnett, A., Clark, M., Prince, J., Olivero Sheldon, A. and Vickery B. 2016. Resilient and Connected Landscapes for Terrestrial Conservation. The Nature Conservancy, Eastern Conservation Science, Eastern Regional Office. Boston, MA.