The Decline of Australian Heath Frogs and Summary of Current Threats

Klop‐Toker, Kaya; Wallace, Samantha; Stock, Sarah; Hayward, Matt; Mahony, Michael

doi:10.1016/b978-0-12-821139-7.00145-8

Cited by 4 publications

(5 citation statements)

References 13 publications

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“…While wildfire has previously been considered as a threat to all these species in conservation assessments, this has not been previously quantified (except see Heard et al, 2021). We recommend that wildfire and climate change impacts are prioritized in future conservation assessments of these threatened species, especially since they often occur in isolated populations where there may be limited opportunities for postfire recolonization without human assistance (Klop‐Toker et al, 2022; Mahony et al, 2021; Stock et al, 2022).…”

Section: Discussionmentioning

confidence: 99%

Severe wildfires promoted by climate change negatively impact forest amphibian metacommunities

Beranek

Hamer

Mahony

et al. 2023

Diversity and Distributions

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Aim: Changes to the extent and severity of wildfires driven by anthropogenic climate change are predicted to have compounding negative consequences for ecological communities. While there is evidence that severe weather events like drought impact amphibian communities, the effects of wildfire on such communities are not well understood. The impact of wildfire on amphibian communities and species is likely to vary, owing to the diversity of their life-history traits. However, no previous research has identified commonalities among the amphibians at most risk from wildfire, limiting conservation initiatives in the aftermath of severe wildfire. We aimed to investigate the impacts of the unprecedented 2019-2020 black summer bushfires on Australian forest amphibian communities.Location: Eastern coast of New South Wales, Australia. Methods:We conducted visual encounter surveys and passive acoustic monitoring across 411 sites within two regions, one in northeast and one in southeast New South Wales. We used fire severity and extent mapping in two multispecies occupancy models to assess the impacts of fire on 35 forest amphibian species. Results:We demonstrate a negative influence of severe fire extent on metacommunity occupancy and species richness in the south with weaker effects in the northreflective of the less severe fires that occurred in this region. Both threatened and common species were impacted by severe wildfire extent. Occupancy of burrowing species and rain forest specialists had mostly negative relationships with severe wildfire extent, while arboreal amphibians had neutral relationships. Main Conclusion:Metacommunity monitoring and adaptive conservation strategies are needed to account for common species after severe climatic events. Ecological, morphological and life-history variation drives the susceptibility of amphibians to wildfires. We document the first evidence of climate change-driven wildfires impacting temperate forest amphibian communities across a broad geographic area, which

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Section: Discussionmentioning

confidence: 99%

Severe wildfires promoted by climate change negatively impact forest amphibian metacommunities

Beranek

Hamer

Mahony

et al. 2023

Diversity and Distributions

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“…The terrestrial stage in the amphibian life cycle faces many anthropogenic threats which impact their dispersal and reproductive ability. Among these threats are disease, habitat loss, degradation, and fragmentation, and invasive species [15][16][17][18][19].…”

Section: Threats At the Terrestrial Stage Of The Amphibian Life Cycle...mentioning

confidence: 99%

“…Newly metamorphosed amphibians are at the greatest risk of succumbing to chytrid, with studies finding juveniles exposed to the pathogen having significantly lower survival rates compared with adult frogs that were able to clear infection better [119,137,162]. Various laboratory and field studies have demonstrated the relationship between infection and environmental temperature [15,166], with elevated infection loads occurring within populations found in areas with cooler temperatures [167][168][169]. As a result of its spread across several continents and its impacts on amphibian populations, Bd is considered one of the biggest threats to amphibian populations.…”

Section: Disease: Chytridiomycosismentioning

confidence: 99%

“…Amphibians have received notoriety for being the most threatened vertebrate taxa since their first global assessment in 2004 [14]. Research suggests the most likely explanation for the current amphibian extinction crisis is disease, but declines have been exacerbated by the interaction of multiple anthropogenic threats: drought, wildfires and extreme temperature exacerbated by climate change; habitat loss, degradation and fragmentation; and the introduction of invasive species [15][16][17][18][19]. These threats reduce survival and reproductive output [20], reducing the population size [21,22] and decreasing genetic viability [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

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Complex Organisms Must Deal with Complex Threats: How Does Amphibian Conservation Deal with Biphasic Life Cycles?

Nolan,

Hayward,

Klop-Toker

et al. 2023

Animals

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The unprecedented rate of global amphibian decline is attributed to The Anthropocene, with human actions triggering the Sixth Mass Extinction Event. Amphibians have suffered some of the most extreme declines, and their lack of response to conservation actions may reflect challenges faced by taxa that exhibit biphasic life histories. There is an urgent need to ensure that conservation measures are cost-effective and yield positive outcomes. Many conservation actions have failed to meet their intended goals of bolstering populations to ensure the persistence of species into the future. We suggest that past conservation efforts have not considered how different threats influence multiple life stages of amphibians, potentially leading to suboptimal outcomes for their conservation. Our review highlights the multitude of threats amphibians face at each life stage and the conservation actions used to mitigate these threats. We also draw attention to the paucity of studies that have employed multiple actions across more than one life stage. Conservation programs for biphasic amphibians, and the research that guides them, lack a multi-pronged approach to deal with multiple threats across the lifecycle. Conservation management programs must recognise the changing threat landscape for biphasic amphibians to reduce their notoriety as the most threatened vertebrate taxa globally.

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“…This poor understanding of habitat preferences and calling behaviours is thought to have led to mis-matched survey efforts and false absences in historical surveys conducted across the range (Gill et al 2021). Populations of L. littlejohni also do not appear to be large and densities at breeding ponds are relatively low compared to other Australian tree frogs, resulting in low capture rates at occupied sites (Mahony et al 2020;Klop-Toker et al 2021;Gillespie et al 2015). Whether this low density is due to inherent low population density or due to declines is unknown (Lemckert 2004;Mahony et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Genome-wide SNPs reveals inbreeding, small populations, and strong genetic isolation in a threatened frog (Litoria littlejohni)

Stock

Klop‐Toker

Wallace

et al. 2022

Preprint

Self Cite

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The status of many amphibian populations remains unclear due to undetected declines driven by disease and difficulties in obtaining accurate population estimates. Here, we used genetic data (Single Nucleotide Polymorphisms) to investigate Australia’s poorly understood Littlejohn’s treefrog, Litoria littlejohni across its fragmented distribution. We detected five identifiable genetic clusters, with moderate to strong genetic isolation. At a regional scale, population isolation likely of population crashes, resulting in small populations with evidence of founder effects. Moderate genetic isolation was detected among populations on the Woronora Plateau despite short distances between population clusters. Evidence of recent declines was apparent in three populations that had very small effective population size, reduced genetic diversity and high inbreeding values. The rates of inbreeding detected in these populations combined with their small size leave these populations at elevated risk of extinction. The Cordeaux Cluster was identified as the most robust population as it was the largest and most genetically diverse. This study exemplifies the value of employing genetic methods to study rare, cryptic species. Despite low recapture rates using traditional capture-recapture demographic methods, we were able to derive population estimates, describe patterns of gene flow, and demonstrate the need for urgent conservation management.

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The Decline of Australian Heath Frogs and Summary of Current Threats

Cited by 4 publications

References 13 publications

Severe wildfires promoted by climate change negatively impact forest amphibian metacommunities

Severe wildfires promoted by climate change negatively impact forest amphibian metacommunities

Complex Organisms Must Deal with Complex Threats: How Does Amphibian Conservation Deal with Biphasic Life Cycles?

Genome-wide SNPs reveals inbreeding, small populations, and strong genetic isolation in a threatened frog (Litoria littlejohni)

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