Chapter 10: Assessing Habitat Connectivity


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Peter H. Singleton
U.S. Department of Agriculture, Forest Service,
Pacific Northwest Research Station
Wenatchee, WA
AUTHOR Publications

Brad McRae
Spatial Ecologist
Washington Field Office
The Nature Conservancy
Seattle, WA
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powerpoint/teaching resources: Landscape Linkage Modelling - BBAR 2010 presentation

Paul Beier, Dan Majka et al: GIS tools for designing wildlife corridors: includes free CorridorDesigner & Land Facet Tools

Paul Beier: Example linkage designs and corridor analyses downloadable PDF libaray

Brad McRae and Darren Kavanagh: LinkageMapper design tools Linkage Mapper is a GIS tool designed to support regional wildlife habitat connectivity analyses. It consists of several Python scripts, packaged as an ArcGIS toolbox INTERACTIVE MAPS of Habitats (click on thumbnail to pan/wheel to zoom, 'view larger' to open window)

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View Larger Map

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Example Corridor Design (view larger) From Paul Beier's "Arizona Missing Linkages" Project, an example map service of one of his corridor designs, for the Tucson-Tortolita-Santa Catalina Mountains Linkage "To begin the process of designing this linkage, academic scientists, agency biologists, and conservation organizations identified 21 focal species that are sensitive to habitat loss and fragmentation, including 12 reptiles and amphibians, 1 bird, and 8 mammals...To identify potential routes between existing protected areas we used GIS methods to identify a biologically best corridor for each focal species to move between these wildland blocks. We also analyzed the size and configuration of suitable habitat patches to verify that the final Linkage Design provides live-in or move-through habitat for each focal species."


SWAP Plan Priorities : The National SWAP Conservation Priorities layer includes data from each state that completed maps showing locations across the landscape that are priorities for conservation. This data set was compiled by Defenders of Wildlife, and the data was merged by NatureServe and National Geographic. The data was compiled in order to display all State Wildlife Action Plan conservation priority areas across the country.



Management landscape for jaguars in the Upper Paraná Atlantic Forest ecoregion. by Carlos De Angelo, Agustín Paviolo, Thorsten Wiegand, Rajapandian Kanagaraj, Mario S. Di Bitetti

BOOK EXCERPT: Animals move across landscapes to acquire food, reproduce, migrate, and shift in response to environmental change or other evolutionary pressures. In fact, most ecological processes happen within a spatial context that influences how those processes occur across a landscape. Examples include nutrient cycling, seed dispersal, range shifts of interacting species, and many others (Crooks and Sanjayan 2006). Landscape features, including patches of natural vegetation, agriculture, urban areas, and major highways, can influence how these processes proceed within an area. Understanding how heterogeneous landscapes provide for or inhibit ecological flows at a variety of scales is important for responsible land management and conservation. The degree to which a landscape allows these flows to occur can be described in a broad sense as connectivity...Thus, connectivity assessment is a spatially explicit concept involving movement or flow. To help understand it, here are some important terms:
• Barrier: A landscape feature that obstructs the movement of an animal or ecological process
• Corridor: A linear, connected land area that joins habitat blocks or sources of ecological flows to provide opportunities for the movement of animals or ecological processes
• Fracture zone: An area of reduced landscape permeability between blocks of habitat or sources (see below) of ecological processes
• Landscape permeability: The quality of a heterogeneous land area to provide for passage of animals or other ecological functions (Singleton et al. 2002)
• Least-cost corridor: The set of map cells for which the least-cost path distance between two sources passing through the cell falls below a user-defined threshold
• Least-cost distance, weighted distance, or cost-weighted distance: The least accumulative cost distance (the sum of cell size times resistance of the cell) to the nearest source
• Least-cost path: The one-cell-wide path between two sources with the least accumulative cost distance (the sum of cell size times resistance of the cell for the cells along the path)
• Resistance, friction, or cost surface: A map of how much the habitat characteristics at each map cell facilitates or impedes the movement of an animal or ecological process
• Sources or nodes: Patches of habitat or origins of an ecological process that serve as the features between which linkages are modeled using least-cost distance or other approaches; not a source in the context of population source<en>sink dynamics; often referred to as “cores”.”...Linkage assessment maps can provide a broad-scale vision to bring together a wide spectrum of stakeholders. These maps show the interconnectedness of large landscapes and can be very effective for fostering cooperation in landscape management and conservation planning.

3-Scale & Time
4-Land Cover
5-Land Use
6-Focal Species
7-Habitats: Terrestrial
8-Habitats: Marine/Aq
9-Habitat Cores
11-Viability Analysis
13-Climate Change
14-Processes & Tools

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