Severe Climate Impacts Beyond Water Stress: The Future of Frogs and Toads in a Warming World

A new study published in Nature indicates that climate change could lead to severe water stress for frogs and toads, with up to 33.6% of their habitats potentially becoming arid by 2100. The research highlights that nearly 41% of amphibian species are at risk of extinction, mainly due to increasing drought conditions. The study maps the combined effects of warming and drought on anuran survival, demonstrating significant physiological impacts under various climate scenarios.

Research has revealed alarming projections regarding the future of frog and toad populations due to climate change, highlighting severe water stress that may result in significant habitat loss. A recent study, published in the journal Nature, suggests that by the end of the century, between approximately 15.4% and 36.1% of habitats occupied by anurans may become increasingly arid because of worsening drought conditions. This assessment was conducted under two distinct climate scenarios: an intermediate warming scenario with a 2 degrees Celsius increase from pre-industrial levels and a high-emission scenario resulting in a 4°C rise. The 2023 Second Global Amphibian Assessment, as emphasized by the International Union for Conservation of Nature’s Red List of Threatened Species, underscores the dire state of amphibian species, with nearly 41% at risk of extinction, establishing them as the most threatened group of vertebrates. The findings indicate that heightened aridity within their current habitats will likely double the rates of water loss in amphibians. Such conditions are expected to adversely impact their movement and reproduction, alongside increasing their susceptibility to disease. The study further investigates the interaction between drought and temperature increases on anuran physiological functions and survival. The results indicate that under the intermediate warming scenario, approximately 6.6% of areas currently inhabited by anurans are projected to become arid by century’s end. In the context of the high-emission scenario, the figure could escalate to as much as 33.6%. Regional assessments predict that by 2080-2100, about 15.4% of environments where anurans reside are likely to encounter more intense, frequent, and prolonged droughts. Notably at risk are regions across the Americas, southern Africa, Europe, and southern Australia, with the Amazon and Atlantic forests facing particularly acute threats. Moreover, the study explores various water conservation strategies among different species of frogs, including ground-dwelling, arboreal, and burrowing frogs, utilizing biophysical simulations. It was noted that within tropical environments, frog activity declined across all projections; warmer temperatures alone led to a decrease of 3.4%, while drought conditions contributed to 21.7%. Additionally, when both warming and drought conditions were combined, there was a decrease of 26% in activity. The impacts of simultaneous warming and drought conditions appear to diminish frogs’ physiological functions, adversely affecting their thermal tolerance as well as their optimal body temperatures. Prolonged dehydration exacerbates locomotion capabilities, further jeopardizing survival rates. Amphibians utilize evaporative water loss (EWL) as a means to regulate body temperature under extreme heat; however, reliance on EWL can lead to dehydration and heightened energy demands. Such physiological trade-offs negatively influence mating behaviors, mobility, and foraging abilities, thereby affecting overall population dynamics. The study concluded that ecotypes occupying stream and semi-aquatic habitats are likely to face greater risks associated with desiccation distress than those inhabiting arboreal or fossorial environments, stemming from their distinct adaptations to water availability in their ecological niches. While some amphibians demonstrate phenological plasticity, indicating potential resilience to climate alterations, researchers emphasize that the ability to acclimate is crucial for the survival of these species in an increasingly arid world. The findings render a stark assessment of the dual threats posed by climate-induced warming and environmental drying on the future of anuran species.

The significance of this topic lies in the increasing evidence of climate change’s impact on biodiversity, particularly for amphibian species like frogs and toads. Amphibians are critical indicators of ecosystem health and serve vital roles in food chains. The urgency of addressing climate implications for these species stems from the fact that they are the most threatened class of vertebrates, with nearly half of all species at risk of extinction. This research is essential for understanding the specific environmental stressors that amphibians face and highlights the necessity for conservation efforts and strategies to mitigate these risks.

In conclusion, the findings from the study underscore the grave challenges that frogs and toads are likely to encounter as climate change progresses, leading to substantial habitat loss and increased water stress. With projections suggesting that significant portions of their habitats may become arid by the end of the century, it is imperative for conservation efforts to consider these factors in order to protect these vulnerable species. As amphibians serve as crucial ecological indicators, the health of their populations is directly linked to broader environmental conditions, emphasizing the need for immediate action to address climate change.

Original Source: www.downtoearth.org.in