Reconstructing Spatial Activity of Past Wildfires in the National Key Deer Refuge on Big Pine Key, Florida

Keywords: National Key Deer Refuge, South Florida Slash Pine, Fire Scarring, Big Pine Key, Fire History, Wildfire, Dendrochronology, Fire Activity, rockland, ecosystem
Abstract Type: Poster Abstract

Abstract

Fire disturbance is essential in ecosystems for maintaining habitat and vegetation. Fire regimes in pine rocklands naturally follow a pattern of high-frequency, low-intensity fires. This curtails fuel load accumulation and preserves fire-tolerant plant species composition. In 2011, a prescribed fire escaped control in pine rocklands on Big Pine Key and burned near a residential area, causing community backlash. South Florida Slash Pine (Pinus elliottii var. densa) is the dominant canopy tree species in the dry rockland ecosystem of the National Key Deer Refuge. Previous work reconstructed fire regimes for pre- (1911-1956) and post-management (1957-2014) periods, evaluating fire history metrics for two levels of burn percentages. This found fire return intervals were statistically different for both periods (p < 0.01) but similar for > 10% and > 25% fires (p > 0.10). Composite fire interval results show that fires burn approximately once every three years. To build on the reconstructed fire activity, we used GIS to spatially analyze fire activity for each of the 21 major fire years (> 25%). We generated raster surfaces of large fires using Inverse Distance Weighted and Kriging methods on the fire-scarred tree data. We found that fires burned in different spatial arrangements for each major fire year in various locations across the study area. The 2011 fire was no more spatially extensive than other large fires in the dataset. These results support those of the time series analyses previously conducted and help show the 2011 fire was a healthy, beneficial fire to the ecosystem.