Without being aware of it, my previous post about the axolotl in Mexico marked the first of several consecutive posts dealing with salamanders. However, after putting the blogpost online I remembered that this year has been designated ‘year of the salamander’ by several conservation groups and that therefore it would be valuable to write some other blogposts to celebrate this. If I look back at my two years of blogging now, I have given the group of the salamanders relatively little attention (with the exception of my reports on the Fire salamander in the Netherlands), while I cannot really think of a good reason why, except a personal preference towards anurans (toad and frogs). That is certainly not very objective of me! In my defense, the media and also scientists seem to have exhibit this same preference for anurans, probably due to their bright colors and photogenic appearance and the higher biodiversity found among this group. Still, salamanders as a group show great variety and their behavior, ecology and appearance can be just as interesting as that of anurans. I guess my personal preference for small, mainly tropical and hopping creatures should not stand in the way of giving the attention to all amphibians, especially considering that salamanders are not at all faring better than their amphibian cousins. So this blogpost I will devote exclusively to make you understand why we need a year of the salamander.
The organization Partners in Amphibian and Reptile conservation (PARC) has dedicated 2014 exclusively to the salamander to energize salamander education, research and conservation. To this end they have partnered up with many different institutions and organizations who are all contributing to save these animals. They use several approaches towards this goal, by for instance raising awareness on the importance of salamanders to ecosystems and humankind (i will discuss this in a next blogpost as well), on the research that is being carried out to better understand these creatures and what is threatening them and also by taking actions in conserving populations and their habitats. Raising awareness is of vital importance, as even for more mediagenic species like frogs (whose conservation message therefore might come across better), people hardly go beyond thinking of them in terms of ‘cute’ or ‘beautiful’, while thinking of them in terms of ‘important part of the ecosystem’ and ‘crucial for human survival’ would probably put more people into action. Information is essential, so that people can base their actions on solid understanding of their environment.
The PARC has done a great job of making information available on their website and I would just like to briefly summarize it here; for a more thorough review of salamander ecology and diversity I refer gladly to their publication ‘State of the Salamander’. Of the more than 7000 species of amphibians (and counting) 670 species, or roughly 10%, belong to the group of the salamanders. The size ranges from the less than 2 centimeters of the Mexican salamander Thorius arboreus to as much as the 1.8 meters of the Chinese giant salamander (Andrias davidianus). Even though amphibian hotspots are mostly found in the tropics, with for example the Tropical Andes exhibiting a very high diversity of amphibian species, salamanders are mostly found in temperate regions. The USA and Mexico represent the two countries with the highest species richness, while considerable species numbers can also be found in Central America and in the Asian countries of China and Japan. Although lagging behind these countries and regions, Europe is still home to 36 different salamander species.
All species survive on an entirely carnivorous diet with larger salamanders even eating frogs, small mammals and other salamanders. While many species are terrestrial, some of them are strictly aquatic, and all of them rely on water for their survival and reproduction, with at least a need for a moist habitat (desiccation is a great risk for them). Due to their permeable skin they are, just like frogs, sensitive to any pollution and provide a good indication of the health of an ecosystem. And, what might come as a surprise to many, salamanders are considered to be one of the most abundant vertebrates in grasslands, forests and wetlands, although their elusive nature makes them hard to spot.
Even though they are so abundant in some ecosystems, the number of salamander species that is considered to be under threat, according to the IUCN, amounts to almost half of all known species. This number is higher than the 1 in 3 species of frogs that is currently under threat, a group of animals that is already seen as a highly threatened one. In the light of this fact it is an absolute necessity that more conservation and research efforts are directed towards the survival of the salamanders. The causes for their dwindling numbers are manifold, but habitat destruction has been assigned as the major threat to salamanders. Clearing of forests to increase the area of agricultural land or simply converting nature into development areas are activities that have a very negative effect on them and are continuing at an unprecedented rate. Logging of trees or logging a whole forested area has a profound impact on the microclimatic conditions in the leaf litter, where many species live, increasing exposure to the sun and lowering humidity, both unfavorable to salamanders. Among other agents of decline peer the usual suspects like habitat fragmentation, pollution and invasive species. Three others I want to discuss briefly: exploitation of salamanders, climate change and diseases.
In many parts of the world salamanders are captured and sold for the pet trade: in the United States alone 20 million are sold annually. I myself was once owner of a fire-bellied newt (Cynops spp.) and although they are beautiful and interesting animals and I tried to care for it well, I had no idea where it came from exactly, and so it might have been taken from the wild thereby impacting the remaining population. But in Asia people behave even worse towards these animals: they are sold as keychain pets and souvenirs and without food and new water they die a slow and horrible death within weeks. The largest of the salamanders, the Chinese giant salamander, on which I will report in a next blogpost, is highly valued for its meat in China and therefore populations have been decimated.
Climate change can have a large impact on salamander species as well: many species are restricted to a small area, because they can only survive in a particular habitat and are unable to travel large distances. A change in climatic condition in their habitat can therefore have devastating consequences. More extreme weather, for instance hotter and drier conditions, can make breeding ponds unavailable and can hinder migration of salamander species. Luckily every single individual can help abate climate change by choosing a lifestyle with a lower carbon footprint. And finally, diseases like chytridiomycosis and ranavirus have been found to be the causes of mass mortalities in salamanders as well. To add to that, in an earlier blogpost about the Fire salamander I have written about a new fungal disease, comparable to chytridiomycosis, that had been discovered in salamanders in the Netherlands and Belgium and has been proposed as the cause of their decline. Our constant moving around the world and sending goods around the world has probably facilitated the spread of these diseases. In short, salamanders don’t have much to cheer for at this moment, but we can make a difference for their future if we are willing to adopt a more sustainable lifestyle.