New methods to calculate wildlife corridors

A common method for identifying potential corridor paths is to use least-cost modeling, which uses a resistance surface to calculate different paths with the lowest cumulative resistance between source and destination locations. However, this type of modeling rarely takes into account the length of the path calculated, which may differ in value for an organism depending on how far it needs to move. In their new paper, Parks and colleagues incorporate the idea that since a corridor’s probability of use likely occurs on a gradient that depends on the dispersal capabilities of a species, corridors generated from least-cost modeling should be weighted by length. This approach to weighting paths has never been explicitly tested before, and has great implications for how scientists and managers create recommendations for corridor conservation.

The researchers used a set of five weighting schemes based on differing dispersal assumptions or conservation objections for wolverines (Gulo gulo), and then ask whether the locations of key connectivity areas changed based on the different schemes. They found that there was a significant difference between weighting schemes, and that which scheme is most useful depends on what type of movement patterns the corridor is meant to support. The results imply that in order to plan for successful corridors, it is necessary to match the corridor to its intended use, whether that is demographic rescue, genetic rescue, recolonization, or some other goal. By doing so, corridors are more likely to be used and therefore more effective in achieving their conservation or management goals.