Hurricane effects on subtropical pine rocklands of the Florida Keys

Abstract

We investigate the effects of Hurricane Wilma's storm surge (23-24 October 2005) on the dominant tree Pinus elliottii var densa (South Florida slash pine) and rare plant species in subtropical pine rocklands of the Lower Florida Keys. We examine the role of elevation on species abundance in 1995 (Hurricane Betsy in 1965 (Hurricane Georges in 1998 (Hurricane Wilma in 2005 to investigate if hurricanes influence abundance by eliminating plants at lower elevation on Big Pine Key, the largest island in the Lower Florida Keys. We compare densities before and after Hurricane Wilma over the 2005-2008 sampling period and examine the role of elevation on changes in pine and rare species densities three years after Hurricane Wilma. We use elevation to assess the impact of hurricanes because elevation determined whether a location was influenced by storm surge (maximum surge of 2 m) in the Lower Florida Keys, where pine rocklands occur at a maximum elevation of 3 m. In 1995 (30 years after a major storm), elevation did not explain the abundance of South Florida slash pine or Chamaecrista lineata, but explained significant variation in abundance of Chamaesyce deltoidea. The latter two species are rare herbaceous plants restricted to pine rocklands. In 2008, 3 years after Hurricane Wilma, the positive relationship between elevation and abundance was strongest for South Florida slash pine, C. deltoidea, and C. lineata. Effects of Hurricane Wilma were not significant for rare species with wider distribution, occurring in plant communities adjacent to pine rocklands and in disturbed rocklands. Our results suggest that hurricanes drive population dynamics of South Florida slash pine and rare species that occur exclusively in pine rocklands at higher elevations. Rare species restricted to pine rocklands showed dramatic declines after Hurricane Wilma and were eliminated at elevations <0.5 m. Widely distributed rare species did not show significant changes in density after Hurricane Wilma. Abundance increased with elevation for South Florida slash pine and C. lineata after the hurricane. In an environment influenced by sea level rise, concrete plans to conserve pine ecosystems are warranted. Results from this study will help define conservation strategies by strengthening predictive understanding of plant responses to disturbance in the backdrop of sea level rise.

Conspecific Plasticity and Invasion: Invasive Populations of Chinese Tallow (Triadica sebifera) Have Performance Advantage over Native Populations Only in Low Soil Salinity

“…In addition to creating waterlogged and anoxic soils, hurricanes will increase electrolyte concentrations and osmotic potential of the soil solution and create a stressful, high salinity environment for both native and invasive plants [2]–[5]. Phenotypic plasticity, the potential of specific traits of a genotype to be expressed differently in distinct environments, is one of the mechanisms by which invasive plants can tolerate wide environmental variation and obtain an advantage in changing environments [6].…”

Fawn Counts and Adult Female Site Use Are Mismatched Indicators of Habitat Quality in an Endangered Deer

“…Previous research has suggested that key deer prefer upland habitats including pine rocklands and upland hammocks [7], so we used a LiDar-derived digital elevation model to examine these habitat associations at a high resolution. We calculated the mean elevation within a 25 m buffer centered on the cameras because elevation is the driver of habitat changes in the Keys, but also reflects the susceptibility of sites to flooding and saltwater incursion from storms and hurricanes [22]. We used a buffer-wide average because some sites were artificially elevated on old roads and berms.…”

Investigation of sedimentary records of Hurricane Irma in sinkholes, Big Pine Key, Florida

“…The contact of these two formations occurs at BPK, which is the Miami Limestone, averaging 5.7 m in thickness, and overlies the Key Largo Limestone (Hanson, 1980). The Miami oolitic layer can prevent the mixing of freshwater and saltwater, which protects BPK groundwater from saltwater intrusion (Saha et al, 2011).…”