To determine the responses of insects and spiders to fire at ground level, Jim uses randomly-located white bowls as traps on the ground in burned scrub and, as a control, in unburned scrub. He operates them at regular intervals post-burn. This photo was taken 1 wk after the burn on Feb. 12, 2001.
Each year Jim locates burrows of Geolycosa spiders and marks them with stake flags, red flags for G. xera archboldi and blue ones for G. hubbelli, then he determines their densities in permanent plots in oak scrub. As shown here, he found many burrows in Feb. 2003, two years after the Florida scrub was burned. But in long-term studies of these burrowing wolf spiders, he finds their densities decline drastically 3-10 years after a burn as gaps of open sand rapidly diminish due to growth of native shrubs. Hence, the spiders, like many other species endemic to scrub, require periodic fires in order to persist.