The fate of Data Deficient amphibian species
In 2008, a rather large book titled ‘Threated Amphibians of the World’ was published by the IUCN that contained summaries of all of the amphibians that had been assigned IUCN Red List categories following the Global Amphibian Assessment (GAA). Some 1,900 species are listed in detail including illustrative maps, photographs, information on the threats and notes on species ecology. I personally picked up a copy back in 2012 and then it was already out of date. There is one worrying thing about the whole book and that is the Data Deficient (DD) amphibian species are listed in one of the many appendices. Almost a decade ago, there weren’t so many amphibian species listed as DD, this has since increased due to the rapid rate of new species discovery. One almost paradoxical fact regarding amphibian conservation is that we are a discovering new species on average every 2 days or less. This is something we’ll come back to later.
The DD category of which this post concerns is given to a species within the IUCN Red when it cannot be placed in another category, due to insufficient information. Why is this an issue you may ask? Unfortunately this classification leads to uncertainty about whether these species is in fact safe or actually under threat. A couple of years ago, small team of scientists looked at this in some detail (see Nori & Loyola, 2015). When I first read the paper a couple of years back, one startling fact grabbed my immediate attention. Almost a quarter of all amphibian species which have been assessed on the IUCN Red List are currently listed as DD. If we look back to the encyclopaedia sized ‘Threated Amphibians of the World’, we know that this number was much smaller. So why now, a decade later is there so much uncertainty regarding so many amphibian species? As someone whom has worked on amphibian Red List assessments, the answer is very clear.
As I stated earlier, we are discovering new species of amphibians at an incredible rate. Some of these have been thanks to molecular techniques in helping to unlock the secrets of species complexes; others have been due to expeditions taking place in previously unexplored locations. In 2008 when the book was published, only around 6,500 amphibian species were known to science. Now in the tail end of 2017, that figure stands at over 7,700 species. At best most of these species are only known from a single location or region, their ecology isn’t always known but may be inferred using related species as a model and they may already be quite rare. With this lack of information regarding a new species, it is very hard to write a concrete Red List assessment and even with some concrete assumptions, the likelihood is that a newly discovered species is likely to remain DD until more light has been shed on its biology, ecology and life history.
Going back to the paper authored by Nori & Loyola, there were some trends in the data which should not be ignored. They found that DD amphibians have, on average, 81% of their ranges totally outside of protected areas. Conversely, more than half of DD species have less than 1% of their distribution represented in protected areas. This is worrying for a number of reasons, first is human encroachment on available habitats and secondly, does this mean that protected areas are failing? I’m sure we’re all aware that protected areas have been set-up to help pandas or elephants but by completing a quick internet search I was unable to locate ant areas that had been set-up for amphibians. Amphibians are an integral part of ecosystems and if they start to disappear then it can lead to the whole system becoming unstable.
We do however have time to act on this worrying fate despite everything. In their analysis, the authors estimate that the percentage of overlap between species’ range and human-modified landscapes is high was approximately 58%. If we work now to help make our towns and cities more amphibian friendly, then perhaps we can start to turn the tides on amphibian declines and learn more about the species, informing a more appropriate Red List status. There are challenges ahead, many countries that contain a large number of DD amphibian species unfortunately suffer from a number of socio-political issues, this includes African countries, south-eastern Asia, Central America and in the northern region of South America. Maybe if we were able to help support these countries then by doing so, we can indirectly help those countries with conservation assessments, planning and appropriate policy at different levels of government administration.
This all sounds very promising and the number of DD amphibian species is only going to rise as new species are found and described. There seems to be no slowing down of the discovery of previously unknown species which does pose an ongoing issue, but it is one we can hopefully resolve – with time. By December 2018, the Global Amphibian Assessment 2 will hopefully be complete. This involved reassessing all of the previous assessed amphibian species and assessing all of those discovered since. Some of the previous species will no longer be listed as DD due to expanded knowledge being gained on those particular species. Hopefully a fewer number of amphibians will be listed in the GAA2 as DD partly due to this. My closing thought is in regards to species which have recently been discovered, if they are already threatened and time is needed to correctly assess them as such, will they go extinct before the appropriate data is collected to assess them as such?
Nori, J., & Loyola, R. (2015). On the worrying fate of Data Deficient amphibians. PloS One, 10(5), e0125055.
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