POST‐FIRE RECOVERY OF FLORIDA LAKE WALES RIDGE VEGETATION

Abstract

Community responses to fire of five major vegetation associations of the Lake Wales Ridge were investigated during a 5‐yr post‐fire period. Vegetation of southern ridge sandhills, sand pine scrub, scrubby flatwoods, flatwoods, and swales was sampled using permanent line transects and quadrats in both burned and unburned (control) areas. Fire passed through the mosaic of vegetation leaving a pattern of unburned and lightly to severely burned areas. There was little change in soil chemistry (pH, K, P, Mg) with the exception of a short‐lived increase in Ca. Vegetation recovery rates, measured by percentage cover and Horn's Index, were rapid. Typically, less than 2 yr was needed for recovery of poorly drained flatwoods and swale associations and 1 to 4 years for better drained scrubby flatwoods and southern ridge sandhills. Species diversity (H′) increased significantly following fire at poorly drained sites due to increased evenness, but was largely unchanged at better drained sites. There was virtually no change in vascular plant species composition for the sprouting associations. Fire is not a succession‐initiating disturbance in the Clementsian sense. The species present prior to burning either resprout soon after fire or resist fire, thus rapidly restoring the preburn conditions. Limited data suggest fire in the associations dominated by seeding species likewise does not initiate a relay type succession. The ridge vegetation exhibits marked resiliency to fire as a result of an evolutionary history of a stressful environment including winter droughts, acidic, nutrient‐poor sand substrates, and frequent lightning‐caused low intensity burns.