Influence of the El Nino Southern Oscillation on fire regimes in the Florida everglades

Disturbances that are strongly linked to global climatic cycles may occur in a regular, predictable manner that affects composition and distribution of ecological communities. The El Nino Southern Oscillation (ENSO) influences worldwide precipitation patterns and has occur-red with regular periodicity over the last 130000 years. We hypothesized that ENSO, through effects on local weather conditions, has influenced frequency and extent of fires within Everglades National Park (Florida, USA). Using data from 1948 to 1999, we found that the La Nina phase of ENSO was associated with decreased dry-season rainfall, lowered surface water levels, increased lightning strikes, more fires, and larger areas burned. In contrast, the El Nino phase was associated with increased dry-season rainfall, raised surface water levels, decreased lightning strikes, fewer fires, and smaller areas burned. Shifts between ENSO phases every few years have likely influenced vegetation through periodic large-scale fires, resulting in a prevalence of fire-influenced communities in the Everglades landscape.