Revised 14 Mar 2003
These two maps are presented to help understand odonata biodiversity in North America. Feel free to download them and print them for your own use, but they are not to be published without permission. They are presented at a large size so details can be seen within each state.
The first map indicates known regions of highest biodiversity of dragonflies in the Lower 48 states. It must be understood that this picture is in part a consequence of sampling effort (more collecting always leads to larger county lists), but it is also a good indication that biodiversity is highest in the eastern part of the country and, perhaps surprisingly, as high in the Northeast as Southeast.
The second map shows the regions of the Lower 48 that are most poorly sampled for Odonata, as indicated by those counties with fewer than 10 species recorded. This map indicates only sampling effort and is not meant to indicate regions of lower biodiversity, as all counties surely support more than 10 species of odonata. This map was published in ARGIA, newsletter of the Dragonfly Society of the Americas, at a smaller scale.
Both maps are quite up to date from published records and a compilation of county records by Nick Donnelly, but they are at the same time already out of date, as surveying continues all across the country. Some areas, e.g. Georgia and the Texas Panhandle, are already much better known than indicated, but the records are not yet available.