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Bucknell University

Publication Date

Spring 2008

Program Name

Australia: Natural and Cultural Ecology

Abstract

Organisms select habitats that provide the best possible resources necessary to their survival. Organisms may occupy and utilize a home range which requires specific selection of components in their available habitat. Monitoring the threats to a species within their habitats is a crucial tool in conservation and management practices. The Murray-Darling Basin of south-eastern Australia has suffered alterations to its hydrology, flow regime, catchment size and usage, flooding cycles, as well as from vast removal of vegetation in the floodplains since European settlement in Australia in the mid-nineteenth century. Knowledge of the habitat use of a focal species can guide efforts to improve the health of systems vital to the plants, animals, and people of Australia. This study investigated habitat use of the Australian freshwater turtle, Chelodina expansa, in two backwaters of the Lower-Murray River in South Australia. Little is known about the ecology of this cryptic carnivore that inhabits only permanent waters. Habitat use of female C. expansa was located within the terrestrial vegetation of Lake Bonney. We collected qualitative information based on the nest and track selection of the nesting females. Aquatic habitat use was determined by locating animals with radiotelemetry in Horseshoe Lagoon. Habitat availability was determined by the percentage of vegetation cover of each habitat type, and the usage of each habitat type was determined by the location of tracked animals. This species of turtle displayed a preference for areas of undisturbed and moderate vegetative cover in which to excavate nests, and the majority of aquatic habitat use was in structured vegetation, including emergent reeds, aquatic macrophytes and submerged logs, dead trees and root systems. Future conservation and restoration of modified systems, especially of the Lower Murray, should consider both terrestrial and aquatic habitats for threatened species suffering from habitat loss, invasive species, and other dangers.

Disciplines

Animal Sciences | Systems Biology | Terrestrial and Aquatic Ecology

 

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