Effects of prescribed fire on prairie arthropods: An enclosure study

We assessed the relative contributions of in situ survival and recolonizati on to overall recovery of arthropod populations following prescribed fire b y monitoring arthropod morphospecies richness and abundance in enclosed and open plots in adjacent burned and unburned units within two remnant Illino is prairies. Vacuum sampling of arthropods at semimonthly intervals followi ng spring burns at each site indicated that fire strongly depressed arthrop od abundance initially, but that abundance and species richness tended to r ecover toward the end of the summer, mostly due to recolonization from adja cent unburned refuges. Nevertheless, arthropod groups (taxa or guilds) were affected differently by fire, and differences in arthropod species composi tion among burned and unburned plots persisted. Sampled arthropod groups si gnificantly reduced by fire at one or both study sites included springtails (Collembola), deltocephaline leafhoppers (Homoptera: Cicadellidae: Deltoce phalinae), aphids (Homoptera: Aphididae), delphacid planthoppers (Homoptera : Delphacidae), parasitoid wasps (Hymenoptera), and spiders (Araneae). Only one group, typhlocybine leafhoppers (Homoptera: Cicadellidae: Typhlocybina e), exhibited a significant positive response to fire. These results indica te that in situ populations of many arthropod species are substantially red uced by prescribed fire. Thus, to preserve native arthropod faunas, land ma nagers should ensure that unburned refuges are maintained and that the inte rvals between burns are sufficient to allow recolonization of burned areas to occur.