SOURCE, DISTRIBUTION AND ABUNDANCE OF MACROARTHROPODS ON THE BARK OF LONGLEAF PINE - POTENTIAL PREY OF THE RED-COCKADED WOODPECKER

Arthropod diversity, abundance and biomass on 50-70-year-old longleaf pine (Pinus palustris) tree boles were examined to determine the origi n of the prey available to the endangered red-cockaded woodpecker (Pic oides borealis) and the variability of this prey over time. Traps desi gned to capture arthropods crawling on the bark (crawl traps), alighti ng on the bark (flight traps), and crawling on the ground (pitfall tra ps) were operated continuously for 12 months. Flight and crawl traps w ere placed at different heights. One-half of the trees with crawl trap s were fitted with a barrier to prevent arthropods from crawling up fr om the ground. Arthropods were identified to genus from one weekly sam ple per month and subsamples were oven-dried and weighed to estimate b iomass. The arthropod community on the bark included over 400 genera. Crawl trap captures were the most similar to the prey of P. borealis. Arthropod fauna captured in crawl traps had a 58% similarity to pitfal l trap captures and a 60% similarity with flight trap captures. Flight and pitfall trap captures had a 10% similarity. Barriers to arthropod movement up the tree reduced the arthropod biomass on the bolt of the trees by 40-70%. Arthropod biomass was relatively evenly distributed over the tree, but varied seasonally with the highest biomass captured in the fall of the year. In general, the study showed that little of the arthropod biomass on the bark is in the form of arthropods that li ve exclusively in that habitat and that a large portion of the biomass is crawling up from the soil/litter layer. (C) 1998 Elsevier Science B.V.