Using a GIS model to assess terrestrial salamander response to alternativeforest management plans

A GIS model predicting the spatial distribution of terrestrial salamander a bundance based on topography and forest age was developed using parameters derived from the literature. The model was tested by sampling salamander ab undance across the full range of site conditions used in the model. A regre ssion of the predictions of our GIS model against these sample data showed that the model has a modest but significant ability to predict both salaman der abundance and mass per unit area. The model was used to assess the impa cts of alternative management plans for the Hoosier National Forest (Indian a, USA) on salamanders. These plans differed in the spatial delineation of management areas where timber harvest was permitted, and the intensity of t imber harvest within those management areas. The spatial pattern of forest openings produced by alternative forest management scenarios based on these plans was projected over 150 years using a timber-harvest simulator (HARVE ST). We generated a predictive map of salamander abundance for each scenari o over time, and summarized each map by calculating mean salamander abundan ce and the mean colonization distance (average distance from map cells with low predicted abundance to those with relatively high abundance). Projecte d salamander abundance was affected more by harvest rate (area harvested ea ch decade) than by the management area boundaries. The alternatives had a v arying effect on the mean distance salamanders would have to travel to colo nize regenerating stands. Our GIS modeling approach is an example of a spat ial analytical tool that could help resource management planners to evaluat e the potential ecological impact of management alternatives. (C) 2001 Acad emic Press.