The Impact of Prescribed Fire on Moth Assemblages in the Boston Mountains and Ozark Highlands, in Arkansas

Abstract

In addition to the impacts of prescribed fires on forest vegetation, this ecosystem process also has dramatic impacts on associated insect assemblages. For herbivorous, terrestrial insects, fire predictably results in a cycle of initial insect population reduction followed by recovery and growth, in which these insect populations exceed pre-fire abundances. We sought to examine if fire-induced disturbance cycles make prescribed burned areas more or less suitable specifically for moths (order Lepidoptera), which is a major food source for, among others, multiple bat species. We surveyed moth assemblages at 20 burned and 20 unburned sites in the Boston Mountain and Ozark Highland ecoregions of Arkansas, to determine if biomass or abundance of moths differed between areas that had been burned in the past 10 years, and those areas that had never been burned. Samples were collected early (April to July) and late (August to November) in the growing season of 2017 (hereafter early season and late season, respectively). We compared biomass and abundance of all moths, and of five representative moth species, between burned and unburned sites. The five moth species were chosen and considered to be representative due to their high relative abundance, and ease of identification. The five chosen moth species included the banded tussock moth ( Halysidota tessellaris ), white-dotted prominent moth ( Nadata gibbosa ), ailanthus moth ( Atteva aurea ), grape leaffolder ( Desmia funeralis ), and painted lichen moth ( Hypoprepia fucosa ). Results from paired t-tests showed no significant difference in total biomass, or abundance of representative species between burned and unburned sites. However, generalized linear regression models showed significantly higher abundance of moths in areas with high basal area that had been previously burned (β = -0.038 ± 0.004 SE, p <0.0001). Lower number of snags (β = -0.081± 0.0044; p < 0.0001) and more open canopy (β = 0.001 ± 0.0001 SE; p < 0.0001), also increased abundance of moths in an area. Our results show that fire acts as an intermediate disturbance, driving moth populations in the Ozark Mountains of Arkansas.