Biogeography and conservation biology of Florida's Geolycosa wolf spiders: threatened spiders in endangered ecosystems

Abstract

The state of Florida has a complex biogeography which is the product of past sea level changes and associated ocean currents creating numerous inland sand ridge systems which are home to a unique biota adapted to the seasonally dry conditions found on these sandy uplands. Among these xeric-adapted taxa is a suite of wolf spider species in the genus Geolycosa. Geolycosa wolf spiders are habitat specialists and poor dispersers, and many taxa have ranges restricted to specific ridge systems. We found that the six Geolycosa species typical of Florida's scrubs and sandhills (G. escambiensis Wallace, G. ornatipes (Bryant), G. micanopy Wallace, G. patellonigra Wallace, G. hubbelli Wallace and G. xera McCrone) have current distributions that correlate with the historical biogeography of the state. There are species typical of the Lake Wales Ridge and associated ridges (G. xera and G. hubbelli), species found on the more coastal ridges (G. patellonigra and G. micanopy) and species whose ranges are divided by the Apalachicola River drainage (G. escambiensis and G. ornatipes). We also found that Geolycosa wolf spiders tend to occur in species pairs which use different microhabitats: those which burrow in areas covered in leaf litter, and those which use only barren sites. These latter species require habitat management plans that include burns, that maintain the habitat in an open condition.