Landscape Ecology

, Volume 24, Issue 2, pp 253–266 | Cite as

Beyond the least-cost path: evaluating corridor redundancy using a graph-theoretic approach

Research Article


The impact of the landscape matrix on patterns of animal movement and population dynamics has been widely recognized by ecologists. However, few tools are available to model the matrix’s influence on the length, relative quality, and redundancy of dispersal routes connecting habitat patches. Many GIS software packages can use land use/land cover maps to identify the route of least resistance between two points—the least-cost path. The limitation of this type of analysis is that only a single path is identified, even though alternative paths with comparable costs might exist. In this paper, we implemented two graph theory methods that extend the least-cost path approach: the Conditional Minimum Transit Cost (CMTC) tool and the Multiple Shortest Paths (MSPs) tool. Both methods enable the visualization of multiple dispersal routes that, together, are assumed to form a corridor. We show that corridors containing alternative dispersal routes emerge when favorable habitat is randomly distributed in space. As clusters of favorable habitat start forming, corridors become less redundant and dispersal bottlenecks become visible. Our approach is illustrated using data from a real landscape in the Brazilian Atlantic forest. We explored the effect of small, localized disturbance on dispersal routes linking conservation units. Simulated habitat destruction caused the appearance of alternative dispersal routes, or caused existing corridors to become narrower. These changes were observed even in the absence of significant differences in the length or cost of least-cost paths. Last, we discuss applications to animal movement studies and conservation initiatives.


Agroecosystems Atlantic forest Brazil Functional connectivity Corridors Cost distance Dispersal Fragmentation Graph theory Matrix Migration Shortest path 



The authors would like to thank Tania Peña-Baca, Courtney Abshire, Kathrine Behrman, Betsy Reardon, Jesse Lasky, Evan Economo, and three anonymous reviewers for comments on the manuscript.


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Section of Integrative BiologyUniversity of TexasAustinUSA
  2. 2.Jet Propulsion LaboratoryPasadenaUSA

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