Altered community flammability in Florida's Apalachicola ravines and implications for the persistence of the endangered conifer Torreya taxifolia

PLoS One. 2014 Aug 1;9(8):e103933. doi: 10.1371/journal.pone.0103933. eCollection 2014.

Abstract

Plant species and communities often reflect historic fire regimes via ecological and evolutionary responses to recurrent fires. Plant communities of the southeastern USA experience a wide array of fire regimes, perhaps nowhere more marked than the juxtaposition of fire-prone uplands and adjacent mesic ravines along Florida's Apalachicola River. The ravines contain many endemic and disjunct species, most notably the endangered endemic conifer Torreya taxifolia. A rapid decline in T. taxifolia over the past 60 years has been associated with widespread replacement by other tree species. To understand the changes accompanying the shift in ravine composition, we compared leaf litter flammability of nine historic and contemporary species. We measured maximum flame height, flame duration, smoldering duration, mass loss, absorptive capacity, and drying rate. Ordination and perMANOVA suggest the nine species segregated into three distinct groups: the fire-impeding T. taxifolia and Taxus floridana; an intermediate group of three deciduous angiosperms; and a mixed cluster of four flammable species. Results suggest T. taxifolia and T. floridana were fire-impeding species in these communities, while contemporary dominants burn similarly to the upslope pyric species. The increasing presence of fire-facilitating species may portend a shifting fire regime that further imperils T. taxifolia and other rare species in the formerly fire-safe ravines.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Ecosystem*
  • Endangered Species*
  • Fires*
  • Florida
  • Laboratories
  • Plant Leaves / physiology
  • Principal Component Analysis
  • Rivers*
  • Taxaceae / physiology*
  • Trees / physiology

Grants and funding

Funding for this research was provided by the National Science Foundation (NSF) Research Experience for Undergraduates Program (REU 0755466 to S.F. Craig and M.D. Johnson), the NSF Graduate Research Fellowship Program (Grant 1049702 to J.M.M.) and the Mississippi Forest & Wildlife Research Center (http://fwrc.msstate.edu/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.