Decline of an endangered amphibian during an extreme climatic event

Abstract

Abstract. Climate change is a poorly understood, emerging threat to many amphibian species. One of the ways climate change is likely to affect amphibians is through increased recruitment failure associated with more frequent climatic extremes. To understand the risk posed by this threat, we combined 13 years of annual monitoring and multi-scaled habitat modelling at the site (n ¼ 60), pool (n ¼ 105) and nest (n ¼ 170) levels to investigate the decline of the endangered northern corroboree frog (Pseudophryne pengilleyi ), during the most severe drought on record in southern Australia. We documented the local extinction of 42% of P. pengilleyi breeding sites during the climatic extreme. Using logistic regression we investigated habitat variables associated with extinction sites. We found that locally extinct sites now resemble historically absent sites, with fewer pools, less water, and drying-related tree invasion. Extended periods of limited water availability at extinction sites is likely to have restricted breeding, contributing to localised extinctions. Habitat variables recorded at the pool and nest level did not significantly influence P. pengilleyi presence/absence, indicating that site level wetness had an overriding effect. We anticipate that increasing climate variability is likely to disproportionately threaten seasonal pool-breeding amphibian species, exacerbating the global amphibian biodiversity crisis. However, our work with P. pengilleyi suggests there are a range of simple habitat manipulations that could help to ameliorate the impacts.

The impact of severe drought on survival, fecundity, and population persistence in an endangered amphibian

“…), which may in turn strongly affect population dynamics and persistence (Scheele et al. ). This decrease in fecundity could also be the result of density‐dependent factors (which affect larval survival, larval size, and time of metamorphosis) due to the reduction of available breeding sites during a drought leading to a concentration of tadpoles (Berven ).…”

“…In B. variegata, high mortality rates during larval growth are usually a consequence of hydroperiod unpredictability of oviposition sites (Morand 1997). In amphibians in general, a high deficit of rainfall leads to catastrophic breeding failure (Richter et al 2003, Taylor et al 2006, which may in turn strongly affect population dynamics and persistence (Scheele et al 2012). This decrease in fecundity could also be the result of density-dependent factors (which affect larval survival, larval size, and time of metamorphosis) due to the reduction of available breeding sites during a drought leading to a concentration of tadpoles (Berven 1990).…”

“…Many factors contribute to explain this global decline (reviewed by Houlahan et al 2000, Kiesecker et al 2001, including habitat loss and landscape fragmentation (Cushman 2006, Becker et al 2007, disease (Voyles 2009), and biological invasion (Kats and Ferrer 2003). Furthermore, climate change is expected to lead to changes in population dynamics (Griffiths et al 2010, Lowe 2012, species distribution (Scheele et al 2012), and community composition (McMenamin et al 2008). To date, researchers have mainly focused on the two latter areas; the direct impact of climatic factors on demographic parameters and, in turn, population viability remains poorly documented.…”

Capture Probability and Survivorship of the Southern Two-Lined Salamander (Eurycea cirrigera) in Drought and Non-Drought Conditions

“…Salamanders inhabiting low-order streams and adjacent terrestrial environments likely deal with drying in a variety of ways, including emigrating to in-stream refuges (Price et al, 2012) or moving from the terrestrial environment to the streambed (MacCulloch and Bider, 1975). Prolonged periods of insufficient water may ultimately lead to decreased breeding activity (Jansen et al, 2009), reproductive failure (Taylor et al, 2006), decreased survival (Scheele et al, 2012), and changes in occupancy (Price et al, 2012).…”

Amphibian‐mediated nutrient fluxes across aquatic–terrestrial boundaries of temporary wetlands

“…They contain unique species assemblages that are not just subsets of those in larger wetlands and may contribute larger fluxes per unit area than larger or more permanent wetlands (Schriever et al., ; Snodgrass et al., ). Climate change threatens temporary pond species by altering hydroperiod (Junk et al., ; Scheele, Driscoll, Fischer, & Hunter, ). Additionally, habitat fragmentation by roads can negatively impact adult breeding migrations and juvenile emigration; thus, reducing connectivity between aquatic and terrestrial habitats and the distance amphibian nutrient subsidies may be transported (Andrews, Gibbons, & Jochimsen, ; Gibbs & Shriver, ).…”