Climate impacts on Lepidoptera and Odonata communities at California natural reserves

Global climate change is projected to impact the distribution of species in a variety of ways including shifts in both geographical and altitudinal ranges, changes in phenology, and homogenization of communities.  In order to study these changes, it is important to examine sites that have been protected from land use change, and the organisms that are known to be sensitive to climatic variables.  The Hastings Natural History Reservation, Sagehen Creek Field Station, and Santa Cruz Island Reserve have been part of the University of California Natural Reserve System since the 1940’s - 1960’s and therefore provide such sample sites.  Odonates are generally a warm-adapted group, and many species are expected to expand in distribution to higher latitudes and elevations with increasing temperatures. Here we analyze change in species richness of Odonata communities over time in comparison with historical measures of temperature and precipitation to demonstrate climate impacts in these regions.  We use Jaccard’s Similarity Index to measure the similarity of the communities studied.  Change in species richness and similarity is determined based on historical entomology collections housed in Bay Area and Santa Barbara museums.  Based on preliminary data, we expect species richness, particularly of high elevation communities, to increase with time and that communities will become more homogenized.  These findings will not only elucidate impacts of climate change on Odonata communities, but also exhibit the benefits of using digitized museum collections as a means to analyze community change over time.