ArcGIS Extension for Wildlife and Habitat Models

MULTI-SCALE SPATIAL ANALYSIS TOOL - ArcGIS EXTENSION

The Multi-scale Spatial Analysis Tool is an extension for ArcGIS 9.0. The tool is designed to compute probability surfaces for either avian richness classes or probability of observation for individual species, using landscape models developed by Mitchell et al. (2001) and Mitchell et al. (2005). The extension is designed to be generally applicable, requiring only GIS data readily available to forest managers (e.g., overstory type, stand age, etc.) or from the US Geological Survey (i.e., topography, hydrology, etc.).

The Multi-scale Spatial Analysis Tool comes with an installation utility that makes its functions available as a toolbar in the ArcGIS 9.0 work environment. The toolbar contains three point-and-click buttons that generate dialogue boxes that walk the user through the three different functions of the tool: 1) defining and calculating landscape variables to be used in multi-scale landscape analysis, 2) defining how landscape variables will be used to generate probability surfaces, and 3) extracting data and probability surfaces to be used for analyses.

The first function allows the user to identify landscape-level data (e.g., maps of forest cover, hydrology, topography, etc.) to be used in analyses and to select a number of landscape indices (e.g., road densities, forest fragmentation, distance to water, etc.) that will be calculated using the landscape data. Upon execution, the tool calculates the identified indices for each point in space, at multiple spatial extents (i.e., using circular landscapes of 100, 250,...,1000 m neighborhoods around each point), on the landscape of interest. This process results in a series of raster maps representing each index at each scale separately (e.g., one map for forest fragmentation measured for a neighborhood 100 m in diameter, one measured on 200 m diameter, etc.).

The second function of the tool allows the user to identify how the maps representing different landscape metrics are to be used to generate probability surfaces representing the estimated distribution of species richness or abundance of species of interest. The user can construct the probability models by selecting landscape metrics of interest and assigning coefficients to each as well as setting an intercept value. The tool is particularly suited to using statistical models of avian richness or species' distributions, but is not limited to them. The user can specify any model in this function, as long as it makes use of the landscape metrics calculated in the tool's first function. Upon execution, this function will generate and display for the landscape of interest a raster map representing the probability surface that was parameterized by the user.

The third function is designed to aid analysis of probability surfaces by allowing the user to extract values from probability surfaces as well as maps of the landscape metrics used to generate them. The function does this by allowing the user to overlay a point layer onto the raster layers of interest. Upon execution, the values at the location of each point are extracted from the raster map and added to the table of the point layer.

Literature Cited

Mitchell, M. S., R. A. Lancia, and J. A. Gerwin. 2001. Using landscape-level data to predict the distribution of birds on a managed forest: Effects of scale. Ecological Applications 11:1692-1708.

Mitchell, M. S., S. H. Rutzmoser, T. B. Wigley, C. Loehle, J. A. Gerwin, P. D. Keyser, R. A. Lancia, R. W. Perry, C. J. Reynolds, R. E. Thill, R. Weih, D. White, Jr., and P. B. Wood. 2006. Relationships between avian richness and landscape structure at multiple scales using multiple landscapes. Forest Ecology and Management 221(2006):155–169. [Abstract]

The Multi-scale Spatial Analysis Tool is an extension for ArcGIS 9.0. The tool is designed to compute probability surfaces for either avian richness classes or probability of observation for individual species, using landscape models developed by Mitchell et al. (2001) and Mitchell et al. (2005). The extension is designed to be generally applicable, requiring only GIS data readily available to forest managers (e.g., overstory type, stand age, etc.) or from the US Geological Survey (i.e., topography, hydrology, etc.).

The Multi-scale Spatial Analysis Tool comes with an installation utility that makes its functions available as a toolbar in the ArcGIS 9.0 work environment. The toolbar contains three point-and-click buttons that generate dialogue boxes that walk the user through the three different functions of the tool: 1) defining and calculating landscape variables to be used in multi-scale landscape analysis, 2) defining how landscape variables will be used to generate probability surfaces, and 3) extracting data and probability surfaces to be used for analyses.