Thursday, February 21, 2013
Elfins, not elephants!
Post by Caroline Polgar
When Richard and Abe Miller-Rushing began investigating the effects of climate change on the flora and fauna of New England they searched for historical data on as many different types of organisms as they could find. They discovered an abundance of records detailing the timing of plant flowering and migratory bird arrival dates. Records on insect phenology, however, proved harder to find. Several years later, Richard heard about the Massachusetts Butterfly Club (MBC), a group of dedicated and experienced butterfly watchers. It turned out the MBC had well maintained archives of sighting records of many species of butterflies as reported by its members from across Massachusetts. On the suggestion of Jeff Boettner, an entomologist at University of Massachusetts, Richard decided to focus on elfins and hairstreaks, two genera of relatively small butterflies native to Massachusetts. Ten species were selected for the study, five elfins and five hairstreaks.
The research group that Richard formed (see below) was interested not only in using the MBC records, but also in obtaining even older records of butterfly sighting by obtaining data from butterfly specimens collected throughout Massachusetts and currently maintained as part of the collections of various natural history museums. After travelling the world (but mainly the east coast of the United States) visiting museums and obtaining records, the dataset was finally complete.
Analysis of the data produced interesting and exciting results. Elfins and hairstreaks in Massachusetts were responding significantly to spring temperature by emerging earlier in warmer years. On average, these species are being seen 3.6 days earlier for each increase in temperature of 1°C. This is similar to response rates of butterflies to temperature seen in Europe, and more importantly is fairly similar to response rates of plant flowering and leafing, and bee sighting dates in the same region of the United States. The change in bird arrival dates, on the other hand, are less consistent and on average are not responding as strongly as these other taxonomic groups. If you are interested in learning more about our research, check out the paper, recently published in Biological Conservation.
Richard Primack (Boston University)
Caroline Polgar (Boston University)
Sharon Stichter (Massachusetts Butterfly Club)
Ernest Williams (Hamilton College)
Colleen Hitchcock (Boston College)