Monitoring populations of Heath FrogLitoria littlejohniin the Shoalhaven region on the south coast of New South Wales

Abstract

We monitored populations of the Heath Frog Litoria littlejohni in conservation reserves near Nowra on the south coast of New South Wales. Thirteen 250 m transects located along perennial creeks were surveyed at night once a year for 30 minutes each from 2001 to 2006. The sites covered a range of altitudes and vegetation communities and were surveyed between late August and October. The area has a relatively high population density of L. littlejohni, with animals being detected at 12 of the 13 sites. A period of below average rainfall overlapped the census period from 2002 to 2006 and a wild fire in January 2002 burnt 12 of the study sites. The number of frogs detected after the fire declined from 100 to 46. Subsequent surveys found that the population recovered but not to pre-fire densities. Breeding was evident during each survey by the presence of amplecting frogs, eggs and/or recently hatched tadpoles. Larger tadpoles possibly from the previous year's breeding were detected at some sites. One amplexed pair was retained and laid a total of 194 eggs, which hatched 10-12 days later. The reproductive effort (clutch mass divided by female post partum mass) was 0.34. No L. littlejohni were detected below 130 metres elevation. In 2005 the Plague Minnow Gambusia holbrooki was found at one site and in 2006 the Yabbie Cherax destructorwas found at another site. Predation of eggs and tadpoles from these introduced species may impact on the population of Heath Frog.

Fighting the flames: site-specific effects determine species richness of Australian frogs after fire

“…These variations in frog species richness at site level is consistent with other studies, identifying some increases (Brown et al 2011;Allingham and Harvey 2013;Grundel et al 2015;Mester et al 2015) but also decreases after fire (Cano and Leynaud 2010;Constible et al 2016). Such dichotomous responses occur in Australian frogs, with no discernible effects of fire detected for Heleioporus eyrei, Litoria olongburensis, L. freycineti or Crinia tinnula, but a negative impact was documented for both Litoria littlejohni (Daly and Craven 2007) and Geocrinia lutea (Driscoll and Roberts 1997).…”

“…Some studies show frog species are not obviously affected by fire (Bamford 1992;Lowe et al 2013;, whereas others show some species experiencing population declines. For example, Litoria littlejohni (Daly and Craven 2007) and Geocrinia lutea (Driscoll and Roberts 1997) experienced declines, and one study even documented a local population extinction (Lemckert 2000). Despite the contributions of finer-scale or localised studies elucidating the effects of fire on Australian frogs, we lack evidence across larger spatial scales or for mega-fires, such as those experienced in 2019/ 2020, and those that are predicted to increase under future climate change (Lee et al 2022).…”

Widespread short‐term persistence of frog species after the 2019–2020 bushfires in eastern Australia revealed by citizen science

“…Knowledge of frog responses to fire is particularly limited, and much is derived from studies on temperate pond‐breeding species in North America (Lowe, Castley, & Hero, 2013). Few studies exist on the impact of fire on Australian frogs, and these have typically indicated that frog species are relatively resilient to fires (Bamford, 1992; Daly & Craven, 2007; Driscoll & Roberts, 1997; Lowe et al, 2013; Potvin et al, 2017; Westgate, Driscoll, & Lindenmayer, 2012; Westgate, MacGregor, Scheele, Driscoll, & Lindenmayer, 2018). However, these studies consider relatively low‐intensity fires, a limited number of species and relatively small geographic areas.…”

Survey of the reptiles and amphibians of the montane forests near Tenterfield on the north coast of New South Wales

“…The amount of direct sunlight and the properties of rock to store and radiate heat and provide refuge sites (especially loose rock on rock) were considered significant biophysical components that catered for certain species of reptiles as has been demonstrated in rock outcrops further south in NSW (Pike et al 2011). This correlation between elevated reptile species richness with exposed rock outcrops has been noted for other regions in New South Wales (Daly 2004(Daly , 2006(Daly and 2007. Australian Zoologist volume 35 (4)…”

“…Surveys need to be conducted over a range of nights and in a range of seasons in order to detect all species present and to account for the influence of climatic conditions on detectability. Call playback and tadpole sampling are relatively recent methods used to detect rare species and habitat specialists (eg, Daly et al 2001, Daly et al 2002, Daly and Craven 2007. However, at the time of our surveys the use of such methods was rudimentary.…”