WADE TRACT RESEARCH REPORT
A Profusion of Butterflies after Prescribed Fire
By Jim Cox, Vertebrate Ecology Scientist
It can be difficult to muster enthusiasm for field work during the mid-August heat, but a recent survey conducted on the Wade Tract left researchers nearly dancing a jig on a 90-plus-degree afternoon.
Dean Jue and colleagues were conducting a monthly survey of butterflies on the Wade Tract this past August and came across one of the rarest butterflies in our region, the Mottled Duskywing (Erynnis martialis). Much to their surprise, they observed at least 8 individuals, certainly the highest number recorded in recent years in south Georgia, and they also managed to get great photos of their eggs on the species’ host plant, New Jersey tea (Ceanothus americanus).
It had been over a year since the scientist from Florida State University had seen this elusive butterfly, and what made the find especially dance-worthy was that it occurred following the extensive application of prescribed fire on the Wade Tract this year. About half the tract is burned during a normal year, but this year the entire tract was burned on two occasions in an effort to help control hardwood brush. Dean and his collaborators were concerned that this strategy might not provide adequate refuge for larval butterflies that are still chomping on leaves in early Spring, and it was great comfort to see that one of the rarest butterflies was not only hanging in there but also occurred in high numbers.
Newly-laid Mottled Duskywing egg on its larval host plant, Ceanothus americanus. The caterpillar feeds exclusively on this plant species until it pupates.
The relationship between prescribed fire and butterflies of southern pinewoods is an area ripe for study. Available information is often anecdotal and incomplete, and many of the adverse effects known stem from studies conducted outside the range of southern pine forests. Prescribed fires conducted in April and May on the Wade Tract lead to a dazzling diversity of butterflies in late Summer and Fall and easily some of the highest counts that Dean’s group has for many butterfly species in the southern Georgia / northern Florida region. On the other hand, extensive burning also may pose a threat in some settings, particularly on smaller management units when burns are not patchy.
Insects lie at the base of the wildlife food chain, and we all know that pollinators such as butterflies provide vital ecosystem functions. There’s still much to be learned about the associations between fire and these many small gems, and, fortunately, outdoor laboratories such as the Wade Tract are providing us with an opportunity to document these relationships.