Effects of exotic grasses on potential fine fuel loads in the groundcover of south Florida slash pine savannas

Abstract

Invasive exotic grasses have been hypothesized to increase fine fuel loads, thereby increasing the frequency and intensity of fires. Most studies, however, have been conducted in habitats in which natural fires do not occur frequently. We investigated the effects of two invasive grass species, Imperata cylindrica and Neyraudia reynaudiana, on potential fine fuel loads of south Florida slash pine savannas, which naturally experience frequent fires during the lightning season. Total above-ground biomass of fine fuels and litter biomass were greater in areas where exotic grasses were present than in nearby areas not containing these grasses. In addition, less above-ground biomass of native species was present in areas where N. reynaudiana was present. The increases in both potential total fine fuels and litter suggest that exotic grass invasions can change fire characteristics, even in ecosystems where fires occur very frequently.