Using GIS to identify potential habitat linkages for swamp rabbit conservation

The distribution and abundance of swamp rabbits (Sylvilagus aquaticus) in southern Illinois have decreased due to loss and fragmentation of bottomland hardwood forests. Remaining suitable habitat is fragmented and most populations are isolated because of limited dispersal across open areas. We used the relative importance of various habitat factors and a GIS to identify the quantity and arrangement of suitable swamp rabbit habitat in southern Illinois. The model was based on a combination of available literature and expert-opinion surveys. The objective of the survey was to gather and quantify expert opinions about habitat suitability and facilitation of movement by asking biologists to rank certain habitat features. Landcover class, hydrology, road classification, and percent canopy cover were normalized and weighted using an analytical hierarchy process, then overlaid in ArcView where the weights for each pixel were summed to calculate habitat suitability score. To validate the model, measurements of current swamp rabbit presence/abundance were overlaid onto the map of habitat scores. There was a high level of concordance between the habitat score and swamp rabbit presence/abundance. A least-cost path analysis was conducted to identify the most permeable portions of the landscape and prioritize areas where connectivity between suitable habitat patches could be increased. Movement costs were also based on literature and expert-opinion surveys. Properties identified by this analysis as critical potential linkages will be evaluated for landowner willingness and eligibility to participate in incentive-based conservation programs aimed at increasing habitat quality and connectivity.