Environmental change in former and present Karner Blue butterfly habitats
The Karner Blue butterfly is a federally endangered species that once was widely distributed throughout 12 states along the northern part of the United States and Ontario, Canada. Now it only exists in seven states. Many factors are considered to have affected the extinction of this species and this study examines the effect of climate change on the persistence of the Karner Blue butterfly. Five sites were selected to study the effect of climate change: Allegan, MI, Fort McCoy, WI, and Saratoga, NY are the three sites that currently have a Karner Blue population while Oak Openings, OH, and Pinery, Ontario are the two sites where the Karner Blue has disappeared. Daily climate data from the 1950s to 2005 were used for calculating 13 climatic indices related to precipitation and temperature. The data were broken into two time periods (pre-1984 and post-1984) to analyze how those indices have changed. Statistical analyses including t-tests and ANOVA and graphs such as time series and box plots were used to compare these indices within two time periods among five sites. The results showed that different indices have changed differently among the five sites. The number of extreme hot days and number of extreme cold days per year have a statistically significant change in the sites where the Karner Blue butterfly disappeared. The precipitation-related indices do not show a statistically significant different trend among the five sites. Temperature seems to have more effect on the existence of the Karner Blue butterfly. Furthermore, butterfly population size and lake effects are also important factors that cannot be neglected. Larger populations seem to have better chances to survive during a dramatic climate change event.
School:Bowling Green State University
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:karner blue butterfly climatic indices climate change
Date of Publication:01/01/2008