Nectar Resources and Their Influence on Butterfly Communities on Reclaimed Coal Surface Mines

Despite the critical role insects play in ecosystem functioning, there has been little study of factors affecting their reestablishment in restored ecosystems. The goals of this research were to quantify the nectar resources provided by reclaimed coal surface mines and to examine the role nectar resources play in determining butterfly community composition on these sites. Adult butterfly communities and nectar resources were sampled on 18 reclaimed coal surface-mined sites and five unmined hardwood sites in southwestern Virginia. Recently, reclaimed sites provided an average of 300 times the nectar abundance of the surrounding hardwoods, and nectar abundance and species richness decreased with time since reclamation. Total nectar abundance was highly correlated with total butterfly abundance and species richness for the entire flight season; these variables were also significantly correlated among sites during most of the 12 sampling periods during the flight season. In only a few cases, however, were butterfly and nectar abundance and species richness significantly correlated within individual sites during the flight season. These results suggest that, although adults of many butterfly species move in response to nectar availability, nectar resources are not sufficiently limiting that their life histories have evolved to maximize nectar resources temporally. While planting species in restored areas that provide abundant nectar will likely attract adult butterflies, this is only one of a number of habitat variables that must be considered in efforts to restore butterfly populations. Finally, adult butterflies appear to have limited utility as indicators of revegetation success.