RT Journal Article
SR Electronic
T1 Butterfly abundance declines over 20 years of systematic monitoring in Ohio, USA
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 613786
DO 10.1101/613786
A1 Tyson Wepprich
A1 Jeffrey R. Adrion
A1 Leslie Ries
A1 Jerome Wiedmann
A1 Nick M. Haddad
YR 2019
UL http://biorxiv.org/content/early/2019/04/18/613786.1.abstract
AB Severe insect declines make headlines, but are rarely based on systematic monitoring outside of Europe. We estimate the rate of change in total butterfly abundance and the population trends for 81 species using 21 years of systematic monitoring in Ohio, USA. Total abundance is declining at 2% per year, resulting in a cumulative 33% reduction in butterfly abundance. Three times as many species have negative population trends compared to positive trends. The rate of total decline and the proportion of species in decline mirror those documented in long-term European monitoring. Multiple environmental changes such as climate change, habitat degradation, and agricultural practices may contribute to these declines in Ohio and shift the makeup of the butterfly community by benefiting some species over others. Our analysis of life-history traits associated with population trends shows an impact of climate change, as species with northern distributions and fewer annual generations declined more rapidly. However, even common and invasive species associated with human-dominated landscapes are declining, suggesting widespread environmental causes for these trends. Declines in common species, although they may not be close to extinction, will have an outsized impact on the ecosystem services provided by insects. These results from the most extensive, systematic insect monitoring programs in North America demonstrate an ongoing defaunation in butterflies that on an annual scale might be imperceptible, but cumulatively has reduced butterfly numbers by a third over 20 years.