title: The Dry Season Shuffle: Gorges Provide Refugia for Animal Communities in Tropical Savannah Ecosystems.
abstract: In the wet-dry tropics, animal species face the major challenges of acquiring food, water or shelter during an extended dry season. Although large and conspicuous animals such as ungulates and waterfowl migrate to wetter areas during this time, little is known of how smaller and more cryptic animal species with less mobility meet these challenges. We fenced off the entire entrance of a gorge in the Australian tropical savanna, offering the unique opportunity to determine the composition and seasonal movement patterns of the small vertebrate community. The 1.7 km-long fence was converted to a trapline that was deployed for 18-21 days during the early dry season in each of two years, and paired traps on both sides of the fence allowed us to detect the direction of animal movements. We predicted that semi-aquatic species (e.g., frogs and turtles) would move upstream into the wetter gorge during the dry season, while more terrestrial species (e.g., lizards, snakes, mammals) would not. The trapline captured 1590 individual vertebrates comprising 60 species. There was a significant bias for captures on the outside of the fence compared to the inside for all species combined (outside/inside = 5.2, CI = 3.7-7.2), for all vertebrate classes, and for specific taxonomic groups. The opposite bias (inside/outside = 7.3, N= 25) for turtles during the early wet season suggested return migration heading into the wet season. Our study revealed that the small vertebrate community uses the gorge as a dry season refuge. The generality of this unreplicated finding could be tested by extending this type of survey to tropical savannahs worldwide. A better understanding of how small animals use the landscape is needed to reveal the size of buffer zones around wetlands required to protect both semi-aquatic and terrestrial fauna in gorges in tropical savannah woodland, and thus in ecosystems in general.
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States of America; School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: J Sean
authors.initials: JS
authors.lastname: Doody
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Simon
authors.initials: S
authors.lastname: Clulow
authors.affiliation: Fenner School of Environment and Society, Australian National University, Canberra, Australian Capital Territory, Australia.
authors.forename: Geoff
authors.initials: G
authors.lastname: Kay
authors.affiliation: Department of Natural Sciences, Daemen College, Amherst, New York, United States of America.
authors.forename: Domenic
authors.initials: D
authors.lastname: D'Amore
authors.affiliation: Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Rhind
authors.affiliation: Queensland Museum, South Brisbane, Queensland, Australia.
authors.forename: Steve
authors.initials: S
authors.lastname: Wilson
authors.affiliation: Department of Terrestrial Zoology, Western Australian Museum, Welshpool, Western Australia, Australia.
authors.forename: Ryan
authors.initials: R
authors.lastname: Ellis
authors.affiliation: Utah's Hogle Zoo, Salt Lake City, Utah, United States of America.
authors.forename: Christina
authors.initials: C
authors.lastname: Castellano
authors.affiliation: Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
authors.forename: Colin
authors.initials: C
authors.lastname: McHenry
authors.affiliation: Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
authors.forename: Michelle
authors.initials: M
authors.lastname: Quayle
authors.affiliation: Stop the Toad Foundation, West Perth, Australia.
authors.forename: Kim
authors.initials: K
authors.lastname: Hands
authors.affiliation: Frogwatch NT, Wagaman, Northern Territory, Australia.
authors.forename: Graeme
authors.initials: G
authors.lastname: Sawyer
authors.affiliation: El Questro Wilderness Park, Kununurra Western Australia, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Bass
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001001:Anura / Q000502:physiology*; D001315:Australia; D055864:Droughts; D065948:Grassland; D008116:Lizards / Q000502:physiology*; D008322:Mammals / Q000502:physiology*; D000068236:Refugium; D012621:Seasons; D012911:Snakes / Q000502:physiology*; D014329:Tropical Climate; D014426:Turtles / Q000502:physiology*; D014867:Water / Q000502:physiology
chemical_list: D014867:Water