title: Remarkable amphibian biomass and abundance in an isolated wetland: implications for wetland conservation.
abstract: Despite the continuing loss of wetland habitats and associated declines in amphibian populations, attempts to translate wetland losses into measurable losses to ecosystems have been lacking. We estimated the potential productivity from the amphibian community that would be compromised by the loss of a single isolated wetland that has been protected from most industrial, agricultural, and urban impacts for the past 54 years. We used a continuous drift fence at Ellenton Bay, a 10-ha freshwater wetland on the Savannah River Site, near Aiken, South Carolina (U.S.A.), to sample all amphibians for 1 year following a prolonged drought. Despite intensive agricultural use of the land surrounding Ellenton Bay prior to 1951, we documented 24 species and remarkably high numbers and biomass of juvenile amphibians (>360,000 individuals; >1,400 kg) produced during one breeding season. Anurans (17 species) were more abundant than salamanders (7 species), comprising 96.4% of individual captures. Most (95.9%) of the amphibian biomass came from 232095 individuals of a single species of anuran (southern leopard frog[Rana sphenocephala]). Our results revealed the resilience of an amphibian community to natural stressors and historical habitat alteration and the potential magnitude of biomass and energy transfer from isolated wetlands to surrounding terrestrial habitat. We attributed the postdrought success of amphibians to a combination of adult longevity (often >5 years), a reduction in predator abundance, and an abundance of larval food resources. Likewise, the increase of forest cover around Ellenton Bay from <20% in 1951 to >60% in 2001 probably contributed to the long-term persistence of amphibians at this site. Our findings provide an optimistic counterpoint to the issue of the global decline of biological diversity by demonstrating that conservation efforts can mitigate historical habitat degradation.
authors.affiliation: Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, SC 29802, USA. gibbons@srel.edu
authors.forename: J Whitfield
authors.initials: JW
authors.lastname: Gibbons
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Winne
authors.forename: David E
authors.initials: DE
authors.lastname: Scott
authors.forename: John D
authors.initials: JD
authors.lastname: Willson
authors.forename: Xavier
authors.initials: X
authors.lastname: Glaudas
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Andrews
authors.forename: Brian D
authors.initials: BD
authors.lastname: Todd
authors.forename: Luke A
authors.initials: LA
authors.lastname: Fedewa
authors.forename: Lucas
authors.initials: L
authors.lastname: Wilkinson
authors.forename: Ria N
authors.initials: RN
authors.lastname: Tsaliagos
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Harper
authors.forename: Judith L
authors.initials: JL
authors.lastname: Greene
authors.forename: Tracey D
authors.initials: TD
authors.lastname: Tuberville
authors.forename: Brian S
authors.initials: BS
authors.lastname: Metts
authors.forename: Michael E
authors.initials: ME
authors.lastname: Dorcas
authors.forename: John P
authors.initials: JP
authors.lastname: Nestor
authors.forename: Cameron A
authors.initials: CA
authors.lastname: Young
authors.forename: Tom
authors.initials: T
authors.lastname: Akre
authors.forename: Robert N
authors.initials: RN
authors.lastname: Reed
authors.forename: Kurt A
authors.initials: KA
authors.lastname: Buhlmann
authors.forename: Jason
authors.initials: J
authors.lastname: Norman
authors.forename: Dean A
authors.initials: DA
authors.lastname: Croshaw
authors.forename: Cris
authors.initials: C
authors.lastname: Hagen
authors.forename: Betsie B
authors.initials: BB
authors.lastname: Rothermel
mesh_terms: D000663:Amphibians / Q000502:physiology*; D000818:Animals; D018533:Biomass; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D005618:Fresh Water; D011156:Population Density; D011157:Population Dynamics; D013022:South Carolina