Habitat characteristics predict occupancy patterns of the endangered amphibian Litoria raniformis in flow‐regulated flood plain wetlands

Abstract

Identification of habitat features that are strongly associated with the occurrence of threatened species is important in terms of predicting impacts of habitat change and identifying key habitats for conservation. In this paper, we apply habitat-based statistical models to predict occupancy patterns of the endangered southern bell frog (Litoria raniformis) across inland New South Wales (Australia). Litoria raniformis previously occupied a wide range of natural and man-made waterbodies across a large geographic range, including flood plain wetlands, oxbow lagoons, irrigation canals and rice bays. Alteration of natural flooding regimes has affected a large proportion of habitats within the historical range of Litoria raniformis, but it is not clear how these changes have influenced habitat occupancy patterns. Fifty-two waterbodies were surveyed for presence/absence of Litoria raniformis in 2001 and 2004. Stepwise logistic regression models were generated to select a subset of variables that best predicted occupancy. Using three predictor variables, vacant and occupied habitats could be predicted with an accuracy of 90% and 70%, respectively. The predictor variables were: the interaction between wetland hydrology and complexity of aquatic vegetation, complexity of fringing vegetation and water temperature. While this study demonstrated that a range of waterbody types were occupied by Litoria raniformis, these habitats shared common hydrological conditions and vegetation characteristics. Altered flooding regimes and reductions in the complexity of aquatic and fringing vegetation are likely to increase the probability of localized extinctions of Litoria raniformis populations. Fig. 2. Modelled probability of occupancy by L. raniformis based on the selected logistic regression results. 1. Ephemeral wetlands, 2. Seasonally flooded wetlands, 3. Permanent waterbodies. Refer to Table 1 for descriptions of variable codes. OCCUPANCY PATTERNS OF L. RANIFORMIS 951

Breeding Habitat and Landscape Correlates of Frog Diversity and Abundance in a Tropical Agricultural Landscape

“…Significant species-specific abundances were associated with percentage of vegetation in the interior of the temporary pools, distance from the pool to the nearest forest fragment, distance to the nearest paved road, and hydroperiod. Our studies emphasize that species diversity cannot be fully explained by considering only local or only regional scales, but requires simultaneous consideration of both (see also Burne and Griffin 2005;Van Buskirk 2005;Karraker and Gibbs 2009;Bickford et al 2010;Shulse et al 2010;Wassens et al 2010;Hamer and Parris 2011).…”

“…Amphibians are often the focus of studies to evaluate questions about the effects of local and regional variables on community structure (e.g., Babbitt et al 2009;Karraker and Gibbs 2009;Werner et al 2009;Bickford et al 2010;Shulse et al 2010;Wassens et al 2010;Hamer and Parris 2011). Amphibian complex life cycles are typically affected by habitat changes operating at different spatial scales.…”

“…Amphibian complex life cycles are typically affected by habitat changes operating at different spatial scales. Most studies relating environmental drivers to amphibian communities have focused on temperate zones (Burne and Griffin 2005;Van Buskirk 2005;Karraker and Gibbs 2009;Werner et al 2009;Shulse et al 2010;Wassens et al 2010). Tropical Brazil supports the greatest frog and toad diversity in the World (AmphibiaWeb 2011), yet few studies have focused on environmental drivers of amphibian communities in this biodiversity hotspot (Myers et al 2000).…”

“…Currently the Brazilian government has no conservation strategy to protect constructed temporary or permanent pools from sugarcane expansion or other human activities. Identification of the habitat features that are associated with the occurrence of anuran species is therefore important for predicting impacts of habitat change and identifying key habitats for conservation (Wassens et al 2010).…”

Spatial dissimilarities in plankton structure and function during flood pulses in a semi-arid floodplain wetland system

“…Humphries et al, 1999;Brock et al, 2003;Jenkins & Boulton, 2003;Iles et al, 2010;Wassens et al, 2010;Ning & Nielsen, 2011;Baldwin et al, 2013b). Environmental water releases are a key management strategy implemented to address the ecological needs of river-floodplain environments (Davies et al, 2014), and often have the aim of restoring structurally and functionally diverse aquatic communities (Ryder et al, 2008;Meitzen et al, 2013).…”