Burrowing Wolf Spiders, Geolycosa spp. (Araneae: Lycosidae): Gap Specialists in Fire-Maintained Florida Scrub

Florida Scrub is a hotspot of biological diversity containing many endemic species such as burrowing wolf spiders (Geolycosa species), that are threatened by habitat destruction. This study investigated why two spicies, G. xera archiboldi (McCrone) and G. hubbelli Wallace, are significantly underrepresented in fire-maintained scrubby flatwoods, a widespread scrub habitat on the Lake Wales Ridge in south-central Florida. Palmettos resprouted within 1-2 weeks after a fire, then in the ensuing months oaks and lyonias dominated the vegetative community. Over the course of 10-11 years after a fire, woody shrubs grew logarithmically in height to form these dense thickets, causing the size of gaps in the vegetation to decline in a log-log fashion as a function of time-since-fire. Gaps in the shrub matrix shrank dramatically on average from about 20 m2 at 0.5 mo postfire to only 0.01 m2 at 120 mo postfire. In contrast, the average size of gaps harboring burrows of adult female spiders was found to be a species-specific trait, independent of time-since-fire: 1.0-1.2 m2 for G. xera archboldi and 0.2-0.3 m2 for G. hubbelli. Hence, gaps suitable for sustenance of both Geolycosa species became uncommon throughout scrubby flatwoods within 11 months after a fire.