Longleaf Pine Characteristics Associated with Arthropods Available for Red-cockaded Woodpeckers

Red-cockaded woodpeckers (Picoides borealis) forage on the boles of living pine trees for a variety of arthropods. To assess the availability of prey under differing stand conditions, we sampled arthropods that crawled up the boles of 300 living longleaf pine trees (Pinus palustrtis) ranging in age from 20-100 years with passive traps over a l-year period. We identified, counted, ovendried, and weighed >50,000 arthropods in 22 ordemand 470 genera. The most diverse orders were the Coleoptera (beetles), Araneae (spiders), and Hymenoptera (ants, wasps and bees). The most abundant orders were the Homoptera with large numbers of aphids (Aphididae) and the Hymenoptera with large numbers of ants (Formicidae). The Coleoptera and Araneae accounted for the greatest available biomass. Overall, arthropod biomass/tree increased with increasing stand age up to approximately 65-70 years, but arthropod biomass/ha was highest in the youngest stands. Abundance and biomass of arthropods on each tree bole were positively correlated with bark thickness and tree diameter, and negatively correlated with basal area (m2/ha). Arthropod biomass differed among seasons, with the highest arthropod biomass occurring in winter and spring. We found no correlation of diversity, abundance, or biomass of arthropods on the tree bole with site index, the numbers of herbaceous plant genera in the understory, the number of herbaceous plant stems, or the percentage of ground covered by herbs. Stand characteristics, such as average bark thickness and diameter, associated with increased arthropod abundance and biomass on the bark are positively correlated to tree age, but these relationships would change with management practices that either accelerated or slowed tree growth. JOURNAL OF WILDLIFE MANAGEMENT 64(1):60-70