Hanula et al: Arthropods and Coarse Woody Debris 229 GROUND-DWELLING ARTHROPOD ASSOCIATION WITH COARSE WOODY DEBRIS FOLLOWING LONG-TERM DORMANT SEASON PRESCRIBED BURNING IN THE LONGLEAF PINE FLATWOODS OF NORTH FLORIDA

A 5-year study of long-term (40 years) study plots was conducted on the Osceola National Forest in northern Florida to determine how dormant-season fire frequency (annual, biennial, quadrennial, or unburned) affects ground-dwelling macroarthropod use of coarse woody debris in longleaf pine (Pinus palustris Mill.) forests. Pitfall traps were used to sample arthropods near logs or metal drift fences of equal length. Samples were identified to genus or the lowest practical taxonomic level. Overall, significantly more arthropods and more arthropod biomass were captured near drift fences than near logs. Similarity of arthropods captured near logs or drift fences ranged from 64.4% in annually burned plots to 69.2% in quadrennially burned plots, with no significant differences noted. Likewise, Shannon diversity, evenness, richness, and number of rare genera were the same for traps regardless of the trap location. Interaction between fires and trap location were observed in 31 of 932 arthropod taxa. Of those, 10 taxa had significantly higher numbers captured in traps near logs in some burn treatments but there was no consistent pattern between log use and fire frequency. In most cases, more were captured in log pitfalls in frequently burned plots but that was not the case for at least 4 taxa. Where interactions between trap location and fire frequency were not significant, arthropods in an additional 101 taxa were captured in higher numbers at 1 trap location or the other. Of those, 73 were captured in higher numbers in pitfalls near drift fences and 28 were captured in higher numbers near logs. Results showed no increase in log usage by general or more mobile ground-dwelling arthropods as more frequent burning reduced the herbaceous and woody under story. However, logs were clearly important to a wide variety of arthropods regardless of burn frequency.