Landscape Characteristics Associated with Active and Abandoned Red-Cockaded Woodpecker Clusters in East Texas

-I investigated spatial characteristics of Red-cockaded Woodpecker (Picoides borealis) cluster sites in the Raven Ranger District of the Sam Houston National Forest, Texas. Active cluster sites were larger and closer to other active clusters than inactive ones and had larger gravity interaction values. Inactive sites were significantly more isolated than were active clusters, they were more likely to be surrounded by inimical land uses, and they were less likely to be connected by corridors of mature timber to active cluster sites. This research indicates that spatial landscape parameters influence Red-cockaded Woodpecker cluster status and they should be considered in management plans for the species. Received 24 Oct. 1994, accepted 16 May 1995. The Red-cockaded Woodpecker (Picoides borealis) is a cooperative breeder with highly specific habitat requirements. Nesting and roosting cavities are excavated in living pine trees that are typically infected with heart-rot fungus (Phellinus pini) and that tend to be the older trees in a forest (Jackson 1977, Conner and Locke 1982, Hooper 1988, Hooper et al. 1991b, Conner et al. 1994). Cavity trees occur in clusters, and the woodpeckers are intolerant of hardwood midstory development in the cluster sites (Loeb et al. 1992, Kelly et al. 1993). Red-cockaded Woodpeckers have declined throughout their range because of a shortage of potential cavity trees (Hooper 1988) and infrequent fire regimes to control midstory development (Conner and Rudolph 1989). Where these problems are absent, populations have been stable or have increased (Hooper et al. 1991a, USFS 1993, Conner et al. 1995). In three of the National Forests in Texas, the Angelina, Davy Crockett, and Sabine, past declines had been precipitous, amounting to a decrease in active clusters of 10% per year between 1983 and 1988 (Conner and Rudolph 1989). However, populations in all National Forests in Texas have stabilized or increased in recent years (Conner et al. 1995). The timber characteristics required for a forest stand to be used by Red-cockaded Woodpeckers are known (Boone 1980, Hooper et al. 1980, USFWS 1985, Walters 1991), but landscape requirements of usable patches have been studied little. Conservation of species requires that adequate areas of habitat are maintained, with the size and configuration of "adequate" habitat differing from spe' Institute of Applied Sciences, University of North Texas, P.O. Box 13078, Denton, Texas 76203-3078. (Present address: Terrestrial Ecology Division, University of Puerto Rico, P.O. Box 363682, San Juan, Puerto Rico 00936-3682.)