Effects of Prescribed Fire on Prairie Arthropods: An Enclosure Study

We assessed the relative contributions of in situ survival and recolonization to overall recovery of arthropod populations following prescribed fire by monitoring arthropod morphospecies richness and abundance in enclosed and open plots in adjacent burned and unburned units within two remnant Illinois prairies. Vacuum sampling of arthropods at semimonthly intervals following spring burns at each site indicated that fire strongly depressed arthropod abundance initially, but that abundance and species richness tended to recover toward the end of the summer, mostly due to recolonization from adjacent unburned refuges. Nevertheless, arthropod groups (taxa or guilds) were affected differently by fire, and differences in arthropod species composition among burned and unburned plots persisted. Sampled arthropod groups significantly reduced by fire at one or both study sites included springtails (Collembola), deltocephaline leafhoppers (Homoptera: Cicadellidae: Deltocephalinae), aphids (Homoptera: Aphididae), delphacid planthoppers (Homoptera: Delphacidae), parasitoid wasps (Hymenoptera), and spiders (Araneae). Only one group, typhlocybine leafhoppers (Homoptera: Cicadellidae: Typhlocybinae), exhibited a significant positive response to fire. These results indicate that in situ populations of many arthropod species are substantially reduced by prescribed fire. Thus, to preserve native arthropod faunas, land managers should ensure that unburned refuges are maintained and that the intervals between burns are sufficient to allow recolonization of burned areas to occur.