Fine-tuning preparations of ecological connectivity maps

Toward Best Practices for Developing Regional Connectivity Maps

PAUL BEIER

WAYNE SPENCER,

ROBERT F. BALDWIN

BRAD H. McRAE

Conservation Biology

Volume 25, Issue 5, pages 879–892, October 2011

Prerequisites needed by people involved in ecological connectivity works are, coarse-grained maps to serve as decision-support tools or vision statements and fine-grained maps to prescribe site-specific interventions. Research has by and large focused on fine-grained maps (linkage designs) covering small areas.

Here the researchers devised 7 steps to coarsely map dozens to hundreds of linkages over a large area, such as a nation, province, or ecoregion. They provide recommendations on how to perform each step on the basis of their experiences with 6 projects: California Missing Linkages (2001), Arizona Wildlife Linkage Assessment (2006), California Essential Habitat Connectivity (2010), Two Countries, One Forest (northeastern United States and southeastern Canada) (2010), Washington State Connected Landscapes (2010), and the Bhutan Biological Corridor Complex (2010).

The researchers say the 2 most difficult steps are mapping natural landscape blocks (areas whose conservation value derives from the species and ecological processes within them) and determining which pairs of blocks can feasibly be connected in a way that promotes conservation.

The researchers point out that decision rules for mapping natural landscape blocks and determining which pairs of blocks to connect must reflect not only technical criteria, but also the values and priorities of stakeholders. They recommend blocks be mapped on the basis of a combination of naturalness, protection status, linear barriers, and habitat quality for selected species. They describe manual and automated procedures to identify currently functioning or restorable linkages. Once pairs of blocks have been identified, linkage polygons can be mapped by least-cost modeling, other approaches from graph theory, or individual-based movement models. The approaches the researchers outline make assumptions explicit, have outputs that can be improved as underlying data are improved, and help implementers focus strictly on ecological connectivity.