Amphibian conservation in a rapidly changing world
The Class Amphibia includes three living orders: the newts and salamanders (Caudata); the frogs (Anura); and the peculiar caecilians (Gymnophiona). According to the online database https://amphibiaweb.org/ there are approximately 817 species of newts and salamanders, around 7 713 frogs and 222 caecilians.
As we all learnt during our junior school years, amphibians are highly dependent on water for their reproduction and survival. It is no surprise therefore that the greatest diversity is found within the tropics in regions of high rainfall. Interestingly through, newt and salamander diversity is greatest in the cooler northern latitudes of North America and Eurasia.
Poytnon’s River Frog (Amietia poyntoni) adjacent to a mountain river in South Africa’s Drakensberg Mountains.
The word amphibian stems from an ancient Greek term amphibios ἀμφίβιος meaning a “double life” in reference to the general lifecycle of most amphibians which return to water to breed, and have the tadpole to adult metamorphosis.
Reproductive strategies in amphibians are truly astonishing and range from fully aquatic to species who nest inside ground chambers, where the young fully metamorphose inside the egg, hatching out as miniature replicas of their parents. Others breed high up in the canopy of trees. Some breed in stagnant water and yet others in fast-flowing ice-cold mountain streams. Advanced levels of parental care have also been observed, such as nest guarding and supplying tadpoles with protein in the form of unfertilized eggs, such as in the South and Central American poison dart frogs.
It is this dependence on aquatic habitats that make amphibians excellent environmental monitors. Sadly, the prognosis is not looking good and the rapid decline in many species is testament to how much we have damaged natural habitats. Added to the fray, habitat destruction, climate change, and disease are wreaking havoc on amphibian populations.
The IUCN publication is dedicated to the late Professor Phil Bishop who played a leading role in global amphibian conservation. Here he is photographed with the author at the 9th World Congress of Herpetology, Dunedin, New Zealand, 6 January 2020.
Amphibian Conservation Action Plan
The IUCN’s Amphibian Specialist Group has just published the latest issue of the Amphibian Conservation Action Plan. This is a collaborative effort by hundreds of amphibian biologists, conservation managers and scientists who have put forward a best practices roadmap for global amphibian conservation. (The link to this publication is provided below.)
Chapter 1 provides a lovely summary overview of amphibian biology and conservation and is an excellent guide to those not familiar with amphibian diversity. It highlights the two global pandemics impacting amphibians – the fungal diseases Batrachochytrium dendrobatidis and Batrachochytrium salamandrovorans.
Amphibians are the most threatened vertebrate class with over 40% listed by the IUCN as threatened. Some estimates are that we have already lost over 200 species to extinction, and despite public awareness and unprecedented conservation efforts, this trend is ongoing. We are going to need a massive investment and commitment from government agencies and the corporate world to reverse this trend.
The Axolotl (Ambystoma mexicanum) is a paedomorphic salamander from Mexico which is highly threatened in its natural habitat around Mexico City but is very popular in the aquarist trade with thousands kept in captivity.
Climate change, with unpredictable changes in rainfall patterns, is also having a detrimental impact, especially on range-restricted species. For example, the East African forest remnant patches which are found from Malawi and Mozambique, north through Tanzania and Kenya, have dozens of unique species found in small, isolated patches. Climate change, harvesting of timber, and slash and burn agricultural practices have placed many of these species on the brink of extinction, along with many reptiles, forest birds, and invertebrates.
Chapters 3 through to 7 outline the major threats, including climate change, ecotoxicology (chemical exposure), habitat loss, infectious diseases, and trade.
Chapters 8 to 10 discuss informed decision making and stakeholder engagement, including advocacy and communications.
The remaining chapters 11 to 14 discuss the latest advances in species management. This includes conservation breeding, assisted reproductive technologies, the use of genomics in amphibian conservation, and challenges, and management of amphibian translocations.
A Natal Sand Frog (Tomopterna natalensis) in a rain-filled pan, Gauteng Province, South Africa.
Globally, there are some excellent ex situ conservation programmes carried out by many zoological gardens and aquariums. This forms a vitally important conservation strategy to ensure species survival, and the idea is to reintroduce them back into their natural environment as soon as the threats can be mitigated and managed. This is where restoration ecology and conservation of wetlands play important roles.
Losing our spectacular amphibian diversity would be a major blow to humankind on so many levels. It would highlight our inability to coexist sustainably with biodiversity and would make us culturally poorer. Water is essential to life and our health and wellbeing, and if we can’t take care of our wetlands from source to sea, we will suffer the consequences. Amphibians also consume thousands of metric tons of pest insects annually, many of which spread diseases like malaria or destroy crops.
A Forest / Natal Tree Frog (Leptopelis natalensis) from Mtunzini, KwaZulu-Natal, South Africa.
Amphibians, especially frogs, have dominated our childhood fairytale stories and opened up a sense of wonder and amazement. Let’s continue telling the story of amphibians in a positive light, and stand in unity for amphibian, and by extension, global biodiversity conservation.
IUCN Amphibian Conservation Action Plan:
https://portals.iucn.org/library/sites/library/files/documents/SSC-OP-057-En.pdf
Text and photographs: Warren Schmidt
