title: Altered community flammability in Florida's Apalachicola ravines and implications for the persistence of the endangered conifer Torreya taxifolia.
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.
authors.affiliation: Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America; Graduate Group in Ecology, University of California Davis, Davis, California, United States of America.
authors.forename: John M
authors.initials: JM
authors.lastname: Mola
authors.affiliation: Department of Forestry, Forest & Wildlife Research Center, Mississippi State University, Mississippi State, Mississippi, United States of America.
authors.forename: J Morgan
authors.initials: JM
authors.lastname: Varner
authors.affiliation: Department of Biological Sciences, Humboldt State University, Arcata, California, United States of America.
authors.forename: Erik S
authors.initials: ES
authors.lastname: Jules
authors.affiliation: Florida Park Service, Department of Environmental Protection, Panama City, Florida, United States of America.
authors.forename: Tova
authors.initials: T
authors.lastname: Spector
mesh_terms: D017753:Ecosystem; D056727:Endangered Species; D005390:Fires; D005431:Florida; D007753:Laboratories; D018515:Plant Leaves / Q000502:physiology; D025341:Principal Component Analysis; D045483:Rivers; D032490:Taxaceae / Q000502:physiology*; D014197:Trees / Q000502:physiology
references.citation: Science. 1999 Jun 11;284(5421):1832-5
references.pmid: 10364555
references.citation: Nature. 2012 Apr 11;484(7393):186-94
references.pmid: 22498624
references.citation: Science. 1962 Jun 8;136(3519):900-2
references.pmid: 17754185
references.citation: Plant Dis. 2011 Jun;95(6):633-639
references.pmid: 30731893
references.citation: Ecol Appl. 2013 Dec;23(8):1976-86
references.pmid: 24555322
references.citation: Ecol Lett. 2012 Jul;15(7):759-68
references.pmid: 22554474
references.citation: Ecology. 2010 Dec;91(12):3481-6; discussion 3503-14
references.pmid: 21302818
references.citation: Am Nat. 2009 Dec;174(6):805-18
references.pmid: 19860540
references.citation: Ecology. 2013 Oct;94(10):2152-9
references.pmid: 24358700