Use of farm dams as frog habitat in an Australian agricultural landscape: factors affecting species richness and distribution

The terrestrial and aquatic attributes of 70 farm dams and five semi-natural waterbodies in the upper Shoalhaven catchment, south-eastern Australia, were examined. Relationships between habitat attributes, frog species richness and the presence of individual species were explored using mixed and logistic models. A positive relationship was found between the extent of native canopy cover in the surrounding landscape and frog species richness, and the occurrence of Litoria peronii and Uperoleia laevigata at farm dams. Annual mean temperature was negatively associated with the occurrence of L. peronii and L. verreauxii, but positively associated with Crinia parinsignifera. Extent of bare ground in the riparian zone and extent of emergent vegetation cover at the water's edge were also useful habitat predictors for several species. Results demonstrate that consideration must be given to both the aquatic and terrestrial environment to develop an understanding of factors influencing frog populations in modified environments and that these factors may vary from species to species. A comparison of species richness and individual models demonstrates that there are limitations associated with reliance upon species richness data to achieve conservation outcomes. Important habitat attributes of the environment may be masked at the species richness level as a result of contrasting responses between individual species. (C) 2001 Elsevier Science Ltd. All rights reserved.