Media ReleaseFrom: Flinders University
With climate action a theme of Earth Day 2020 (22 April 2020), a new research paper highlights the plight of some of the most vulnerable creatures – and shortfalls in most conservation efforts.
More than birds and most mammals, amphibians (frogs, salamander, worm-like caecilians, anurans, etc) are on the front line of extinction in a hotter, dryer climate – including in Australia where wetlands and environmental water flows are under pressure and facing inadequate management.
“Amphibian populations are in decline globally, with water resource use dramatically changing surface water hydrology and distribution,” says Flinders University freshwater ecologist Rupert Mathwin, lead author of the review study published in Conservation Biology.
“Intelligent manipulation and management of where and how water appears in the landscape will be vital to arrest the decline in amphibia.”
However, many conservation measures are not enough to arrest the decline.
“Already about 41% of the species assessed (IUCN 2019) are threatened with extinction, so with continued climate change we have to be smarter about managing water to maintain critical habitats and save our threatened amphibians from extinction,” says Corey Bradshaw, Flinders University Professor of Global Ecology.
“It will be critical to use prior knowledge and change the way we share our successes and failures to find ways to save amphibians.”
The article found some key pointers for future land management:
* Extending the time that water is available in temporary pools is one of the most successful approaches. Excavating, lining and pumping water into breeding ponds helps populations.
* Amphibians are often limited by (mainly) fish predators, so restoring natural drying patterns outside of the main breeding times can reduce predation.
* Spraying water into the environment has been attempted but appears to have limited success (see examples in Conservation Bytes).
· Releasing water from dams along river channels (often termed environmental flow) can harm amphibians if high-energy water flows scour habitat features and displace larvae, and favour breeding of predators like fish.
Much of Australia is drying as a result of climate change, water extraction, and landscape modification, with mass deaths of native fish hitting the headlines last summer. Environmental flows compete with agriculture and other human uses.
Amphibians breathe (in part) through their skin, so they maintain moist skin surfaces. This sliminess means that most amphibians quickly dry out in dry conditions.
Additionally, most amphibian eggs and larvae are fully aquatic. One of the greatest risks to populations are pools that dry too quickly for larval development, which leads to complete reproductive failure.
“This need for freshwater all too often places them in direct competition with humans,” says Professor Bradshaw.
The systematic review, entitled ‘Manipulating water for amphibian conservation’ (March 2020) by R Mathwin, S Wassens, J Young, Q Ye and CJA Bradshaw is available online in Conservation Biology (http://doi.org/10.1111/cobi.13501) DOI: 10.1111/cobi.13501
The 50th anniversary of Earth Day (22 April 2020) comes at a critical time as “climate change represents the biggest challenge to the future of humanity and the life-support systems that make our world habitable” (see earthday.org for Earth Day events).
More photos (please credit KATE MASON)