| Fires are among the most conspicuous disturbances affecting leaf litter communities, and are sources of both direct and indirect insect mortality. Fires historically occurred on the Ozark landscape at high frequencies, and modern forest managers utilize prescribed fire to restore and maintain those ecosystems. I examined fire effects at multiple scales, ranging from post-fire patterns in leaf litter arthropod community structure to responses of individual organisms to heat stress.;This dissertation summarizes the history of fire occurrences in Ozark forests of Arkansas. It then unifies the results of four observational and experimental studies designed to assess how Ozark forest ant communities are impacted by fire. First, I compared the structure of leaf litter ant communities between burned and unburned oak forests. Second, I examined the effects of local fire intensity on arthropod abundance and species richness in 1m 2 patches by manipulating local fuel loads (litter depth). Third, I measured the temperature profiles of different forest microhabitats during fires using temperature indicator plates and compared the results with profiles of prairie fires. Finally, I tested the critical thermal maxima of nine common Arkansas forest ant species.;Prescribed burning generally decreased ant species richness and abundance and increased similarity in species composition among samples. Post-burn ant communities generally were nested subsets of pre-burn ant communities. While different microhabitats experienced a wide range of temperatures during prescribed fires, most arthropods, including ants, did not show consistent responses to variation in local fire intensity. Arthropod recovery rates also were independent of fire intensity. During fires, some microhabitats experienced only minor increases in temperature that were likely sublethal (i.e., < 60°C). The critical thermal maxima of all ants tested were far below the highest temperatures at which fires burned; however, differences in thermal maxima were observed among ant species and body sizes.;This research provides novel information about the ecology of temperate ant communities, the importance of fire intensity in oak forests, and the rule of physiological heat tolerance in surviving fires. Appropriate extensions of this work include examinations of ash toxicity, heat shock protein expression, and behavioral fire avoidance mechanisms. |
