Functional heterogeneity of red-cockaded woodpecker habitat in the Sam Houston National Forest: insights for management

Red-cockaded woodpecker (RCW, Picoides borealis) populations are greatly affected by the fragmentation of forest habitat through the effect on dispersal between active clusters and the other suitable habitat. In order to assess the suitability of a given landscape structure for the maintenance and expansion of RCW populations, land managers need an index that correlates with the bird’s perception of that structure. Rather than assuming that the application of the most common landscape metrics will provide the necessary information, we applied three indices of functional heterogeneity (as opposed to measured heterogeneity) to a GIS coverage of the Raven District of the Sam Houston National Forest using two observable scales. The GIS coverage included information on habitat suitability and RCW cluster distribution and size. The analysis indicated that the presence of cavity trees is the most important factor for RCW population maintenance and that fragmentation of the foraging habitat has much less impact. The analysis also indicated that many areas currently of high functional importance for the RCW are effectively isolate from on another. This second result has significant implications for dispersal of individuals between areas of high functionality and this also the maintenance of RCW in this forest