Bioclimatic analysis of disjunct populations of the giant burrowing frog, Heleioporus australiacus

Abstract

Aim A bioclimatic analysis of the giant burrowing frog was conducted to determine if the northern and southern populations have distinct climatic profiles and to determine if the disjunction in the species records is a result of a climatically unsuitable area. Location The study utilized records throughout the species range in south‐eastern Australia. Methods The bioclim package was used to examine the climatic envelope of the species, as well as envelopes for the southern and northern populations. Principal components analysis (PCA) was used in an attempt to refine the model. Results The package predicted the observed gap between the populations as climatically suitable in all of the models. The northern populations were found in warmer and wetter sites than the southern populations. River valleys and coastal lowlands were generally unsuitable climatically for the species. Main conclusions The area of the observed disjunction is climatically suitable for both the northern and southern populations. Large river valleys appear to have played a significant role in determining the distribution of the species. PCA was used successfully to alter the model, however further research is needed to determine which is the most accurate approach.

Spatial models of giant burrowing frog distributions

“…The association of the species with dry forest habitats predicted in these models is consistent with reports from other studies (e.g. Webb 1987, Lemckert et al 1998, Penman et al 2005b.…”

“…Within this region a number of studies of the species have been conducted, and as a result we have a relatively good understanding of the species biology in this area (Lemckert et al 1998, Lemckert & Brassil 2003, Penman 2005, Penman et al 2005a,b, 2006a. A larger area was not used, as beyond these boundaries records of this species are extremely sparse; for example, to the north there are only approximately 5 records within an area of 500 km 2 (Penman et al 2005b).…”

“…The models were considered unreliable by the authors due to the small number of sample sites relative to the number of variables used and the poor prediction of known sites. Penman et al (2005b) subsequently conducted a bioclimatic analysis of the species distribution, which identified broad distribution trends with river valleys, high peaks and coastal lowlands providing unsuitable habitat. These models, however, did not provide detailed information of any value for managers of the species, as most of these areas have been cleared for agriculture and urbanisation or are within inaccessible areas of conservation reserves.…”

Interactive effects of climate change and fire on metapopulation viability of a forest-dependent frog in south-eastern Australia

“…1). Climate strongly influences the species' current distribution (Penman et al, 2005b(Penman et al, , 2007b and behaviour (Penman et al, 2006a). Longer-term climatic variation has also shaped the species' distributional extent.…”

“…H. australiacus is thought to be composed of two genetically distinct taxa (Penman et al, 2008b), with a geographic division between the two taxa at the current disjunction in the distributional records (Penman et al, 2005b) (Fig. 1).…”