Meeting Abstract
Butterflies are charismatic mesofauna that are sensitive to environmental change and have great potential to inspire conservation mindsets in the general public. We present the results of a macroecological analysis of extinction threat in 6797 species of butterfly (Order Lepidoptera, Suborder Rhopalocera). We used the IUCN threat status of 276 species to create a logistic regression model of extinction threat using body size, geographic range, habitat specificity, rarity (assessed by date of last known observation), and several bioclimatic variables as predictors. We find that body size has very little predictive power for extinction risk, consistent with the hypothesis that size-selective extinction is a signature of human hunting rather than habitat or climate changes. Family membership, geographic range, and rarity are the strongest predictors of extinction threat. Butterflies are one of the best-represented invertebrate groups on IUCN’s Red List. Nevertheless, a very small percentage of known butterfly species have been evaluated. To develop a better sense of global butterfly extinction risk, we applied the regression model to 6521 butterfly species that have not yet been evaluated by the IUCN. The IUCN lists 29% of butterfly species as being vulnerable or more threatened. We find that that the most threatened 29% of unevaluated species have a threat probability of at least 0.24. Moreover, the threat probability is greater than 0.50 for 12.5% of species and greater than 0.75 for five percent of species. Overall extinction threat in butterflies is currently low based on calibration from assessed species; however, ongoing climate change and loss of habitat are likely to cause threat levels to increase across the coming decades.
