Ecosystem Responses to Prescribed Fire Along a Chronosequence in a Subtropical Pine Rockland Habitat

Bryan M. Dewsbury; Suzanne Koptur; James W. Fourqurean

Ecosystem Responses to Prescribed Fire Along a Chronosequence in a Subtropical Pine Rockland Habitat

Bryan M. Dewsbury^1,2, Suzanne Koptur¹^,*, and James W. Fourqurean¹

¹Department of Biological Sciences, Florida International University and School of Earth, Arts, and Society, College of Arts and Sciences, Florida International University, Miami, FL 33199, USA. ²Current address - Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA *Corresponding author.

Caribbean Naturalist, No. 24 (2015)

Abstract
Pinus (Pine) rockland forests are oligotrophic, subtropical habitats whose primary-producer community structure is typically maintained by periodic fire. Contemporary urbanization and mechanized agriculture have reduced this habitat to a fraction of its former range in subtropical South Florida. Most studies of pine rocklands have focused on the timing and intensity of required periodic fire. However, we were specifically interested in the relationships between the soil and foliar biogeochemistry of the plant community and how they might change during secondary succession following fire. Utilizing techniques common in studies of seagrass ecosystems, we employed a chronosequence approach based on the records of prescribed burns at Long Pine Key in Everglades National Park to compare the abundance of dominant species and chemistry of foliage and soil from the year following fire to 7 years after a burn. The return of the community to previous coverage after fire was rapid due to resprouting, and the primary-producer structure returned to its pre-fire state within a year and a half after burning. Some shrub species followed a discernible pattern of increase or decrease in relation to phosphorus changes compared across the chronosequence. Specifically, the abundance and cover of Serenoa repens (Saw Palmetto) was negatively correlated with phosphorus over the sampling period. The results suggest that during succession, though overall species distribution in these systems might not be controlled by nutrients, certain species may serve as indicators for biogeochemical regime shifts over limited temporal scales. The complexity of the plant community in terrestrial habitats is perhaps better described with traditionally employed vegetation analyses, but we suggest that further work could demonstrate that soil- and foliar-nutrient content of key species may be useful as a proxy for successional stage in pine rocklands and other fire-prone terrestrial communities.

Download Full-text pdf (Accessible only to subscribers. To subscribe click here.)