Prescribed Fire as a Butterfly Conservation Tool
Who knew that prescribed fire was an important tool in restoring and conserving imperiled butterflies?
Dave McElveen, Research Associate in the Stoddard Bird Lab, traveled to Maryland recently to help assess how prescribed fire might be used to maintain habitat for the rare Frosted Elfin butterfly (Callophrys irus). Dave was invited there by the Maryland Department of Natural Resources (MDNR) to help determine how vulnerable the Frosted Elfin might be to the use of fire during different life stages.
Dave and a team of MDNR staff and local volunteers collected 40 Frosted Elfin larvae and placed them in enclosures mimicking natural conditions. During the larval stage of their annual cycle, individuals feed exclusively on wild indigo and sundial lupine host plants and lack the wings needed to outrace an approaching flame. After 30 days, the enclosures were carefully searched to locate where larvae ended up as pupae for the next stage of life. Most were in the leaf litter or on the soil surface. This was novel because the pupae often burrow a bit deeper underground in other populations and, as a result, may be more susceptible to prescribed fires set during larval/pupae stages in Maryland.
The Frosted Elfin is imperiled throughout its range due, in part, to habitat changes as a result of fire exclusion. Burning maintains habitat for the butterfly, but it may be important to shift the timing of fires to a time of the year where the butterfly is less susceptible to the heat. This can be especially important for small, isolated populations. The major remaining site in Maryland is a 5-acre pine-oak upland that MDNR wants to restore and maintain using fire. Fire needs to be applied to maintain appropriate conditions, and this new information will help to determine when fires can be applied without decimating this isolated population.
Photos courtesy of Dave McElveen