21 - Where to draw the line: integrating feasibility into connectivity planning  pp. 536-554

Where to draw the line: integrating feasibility into connectivity planning

By Scott A. Morrison and Mark D. Reynolds

Image View Previous Chapter Next Chapter


The long-term persistence of populations in fragmented landscapes depends on connectivity among disjunct habitat patches. Retaining or restoring habitat corridors has become a dominant strategy for maintaining connectivity in fragmented landscapes (e.g., Bennett 1999; Groves 2003; this volume), especially when the surrounding matrix is hostile to dispersing wildlife. The biological merits of any particular corridor, however, will depend upon a variety of factors, including the ecology of the targets (species, communities, natural processes) it is intended to serve, as well as the specific attributes of the corridor itself, the habitat matrix in which it is embedded, and the core areas it is connecting. Often, the effects of corridors on target biota are unknown. In some cases, corridors may be ineffective or even counter-productive (e.g., Simberloff and Cox 1987; Hess 1994; Dobson et al. 1999; Crooks and Suarez Chapter 18). Biological advantages and disadvantages of corridors have been discussed elsewhere (e.g., Beier and Noss 1998; Groves 2003; Crooks and Sanjayan Chapter 1). Here, we focus on how feasibility considerations factor into the decision-making process of conservation practitioners deciding where best to invest resources in connectivity conservation.

In an ideal world, wildlife corridor planning would occur with detailed knowledge of biological resource needs, multiple options for corridor design, unlimited resources for implementation, and cooperative landowners. More often, virtually nothing is known about plant and animal movement needs within a landscape, human land uses have already greatly constrained corridor options, conservation funding is inadequate, and landowners and political entities are recalcitrant (Swenson and Franklin 2000).

Beier, P., and R. F. Noss. 1998. Do habitat corridors provide connectivity? Conservation Biology 12:1241–1252
Bennett, A. F. 1999. Linkages in the Landscape: The Role of Corridors and Connectivity in Wildlife Conservation. IUCN, Gland, Switzerland: International Union for the Conservation of Nature.
Casterline, M., E. Fegraus, E. Fujioka, et al. 2003. Wildlife corridor design and implementation in southern Ventura County. Unpublished group M.Sc. thesis project, Bren School for Environmental Sciences, University of California–Santa Barbara, Santa Barbara, CA.
Dobson, A., K. Ralls, M. Foster, et al. 1999. Corridors: reconnecting fragmented landscapes. Pp. 129–170 in M. E. Soulé and J. Terborgh (eds.) Continental Conservation: Scientific Foundations of Regional Reserve Networks, Washington, DC: Island Press.
Groves, C. R. 2003. Drafting a Conservation Blueprint: A Practitioner's Guide for Planning for Biodiversity. Covelo CA: Island Press.
Hess, G. R. 1994. Conservation corridors and contagious disease: a cautionary note. Conservation Biology 8:256–262
Kremen, C., V. Razafimahatratra, R. P. Guillery, et al. 1999. Designing a new national park in Madagascar based on biological and socio-economic data. Conservation Biology 13:1055–1068
Noss, R. 2003. A checklist for wildlands network designs. Conservation Biology 17:1270–1275
Penrod, K., R. Hunter, and M. Merrifield. 2001. Missing linkages: restoring connectivity to the California landscape. Proceedings of a workshop held November 2, 2000, San Diego, CA.
Simberloff, D. S., and J. Cox. 1987. Consequences and costs of conservation corridors. Conservation Biology 1:63–71
Swenson, J. J., and J. Franklin. 2000. The effects of future urban development on habitat fragmentation in the Santa Monica Mountains. Landscape Ecology 15:713–730
Walker, R., and L. Craighead. 1997. Least-cost-path corridor analysis: analyzing wildlife movement corridors in Montana using GIS. 1997 ESRI International User's Conference Proceedings.