Over the course of our planets history, thousands upon thousands of species of Fauna and Flora has both flourished and blossomed into marvelous species that can be found today, or they have disappeared off the face of earth, either naturally over the course of time or faced severe threats caused by none other than our very own species.
Homo sapiens throughout its existence, has caused the direct or indirect decline and eventual extinction of hundreds of species and in the past 500 years alone, the number of extinct species was estimated at approximately 869 (IUCN Red List – 2007).
Even today, there are still extinctions occurring and currently, there is an estimated figure of 47,978 species of Fauna and Flora listed on the IUCN Red List of Threatened Species. However, even though the everyday ordinary people in the world are aware of the countless projects to save the Clouded Leopard or the Giant Panda, people rarely know or have even heard of the species of Amphibian that are endemic to the island of Madagascar, or even realise the country itself is real or is home to the vast diversity of wildlife. So I think, it would be best to start this article by writing about the island of marvels itself.
Madagascar – In a Nutshell.
Around 88 million years ago, when the prehistoric supercontinent known as Gondwana or Gondwanaland began to separate its land mass into pieces, a small chunk of land measuring 228,900 square miles started to move away from mainland India, this of course is Madagascar. In modern times, it is believed to be one of the largest and oldest islands on earth, and has had more than enough time to create both an amazing array of beautiful landscapes. Being split partly in two by a vast spine of mountains which runs the islands entire length, this has created a unique range of habitats with the Eastern and Northern parts being mainly Lush Rainforests and Swamps, to the Western and Southern lands being a mixture of arid woodland/forests and parched deserts.
With this drastic combination of extended island isolation and varied landscape, it as created some eccentric wildlife, 90% of which can be found no where else in the world, and of this number over 300 species of Amphibia (99.5% of which) are also solely endemic, however more are still awaiting appropriate description and even discovery out of all the species of Amphibia found on Madagascar, 99.5% of them are completely endemic. According to R. G. B. Perl and other researchers, in the article titled “DNA Bar-coding Madagascar’s Amphibian Fauna”, it is listed that just over 500 species are to be found within their country of origin, but it is believed that Madagascar actually hosts a greater amount than above said quantity, by approximately 200 species.
However, the island is facing severe problems caused by Human Activity, with serious declines in its naturally occurring habitats. It is believed, since the first settling Humans arrived 1500 years ago, the habitats have declined by approximately 90% or more leaving little condensed pockets of National Parks scattered throughout the island and what is even more concerning, is that 40% of the above percentage has in fact occurred in the past 60 years alone. Because of this increased exposure to previously remote landscapes, there are new risks that the beautifully diverse wildlife faces. With risks from highly invasive species such as the Asian Common Toad (Duttaphrynus melanostictus) and the deadly fungal infection, Chytridiomycosis (Batrachochytrium dendrobatidis), which has already caused the major decline in most the worlds Amphibian species, these unique species are in dire need.
Habitat-loss – Disappearing Refuges
Across most of the Eastern Coast of Madagascar, a technique of agriculture has been in
practice for many, many years causing a drastic decline in the Mantella natural habitats; this method is known as “Tavy” or more commonly as Slash-and-Burn Cultivation. This involves Trees and smaller brush and bushes to be cut down and left to dry out over the course of the winter period when precipitation is at an all time low, and eventually being burnt just before the first Rains arrive. This is mainly to allow the cultivation of Rice or Corn Crops within the regions felled and after only a few years of growing the crops, the people will move on and seek another area to cultivate whilst the previous area is left to fallow.
Due to the incredibly damage this method of Agriculture causes, such as Soil Erosion and destruction of a vast amount of Vegetation, this practice was in fact made illegal, in an attempt to slow the decline of Rainforest within these regions but is still practiced by local peoples to this day. This is mainly because of the lack of realisation and knowledge of the issues that are becoming more and more apparent making the education of locals, a primary aim for a majority of Conservation Organisations.
However, this is not the only cause of Habitat destruction, simple mining and logging has definitely played a major role in the disappearance of major and vital biotopes which has severely fragmented certain Mantella populations. A prime example of such is the amazing but unusual locality variations of the Yellow Mantella (Mantella crocea) which exhibits a completely different colouration from its common name, that is in fact Green. This colouration an be found at Ambohitantely Reserve, the Eastern-central region of the island and also at the Zahamena National Park which is in a North-eastern direction from Ambohitantely, making it roughly 188km (116 miles) apart. This goes to show that the habitat loss is far from small, with locality populations being already drastically fragmented from each other.
Chytridiomycosis – The Amphib Killer.
Chytridiomycosis (or commonly known as Chytrid Fungus) is an emerging infectious disease to the class of Amphibians, caused by the aquatic fungal pathogen, Batrachochytrium dendrobatidis (Bd). There are numerous Chytrid fungi members that can be found within the class of Chytridiomycetes. A lot of Chytrids are what is known as Saprophytes, fungi living on the dead decaying organic matter, arguably making one of their most important ecological functions, decomposition. However Bd, is very unique in comparison to other Chytrids.
Having been first described in 1999, this new species was found to infect (with much success) Amphibian species. What makes this even more unusual, is the fact it is the only Chytrid to parasitically attack a vertebrate species and furthermore, specifically only Amphibians. It is often highly contagious and infection predominately occurs inside the cells of the outer skin layers that contain large amounts of keratin. As you may be aware, Keratin is what hair, feathers and claws are made of and helps by making the outside of the skin tough and more resistant to injury. The biggest trait that Amphibians predominately have is a Permeable skin, which is highly important for Gaseous exchange that can take place with some of the class it also helps with the absorption of important salts (electrolytes) like sodium and potassium through the skin. Chytridiomycosis, changes that entirely, forcing the skin to become thicker due to Microscopic changes that are known as “hyperplasia and hyperkeratosis”. Abnormal electrolyte levels as the result of Bd – damage the skin causing the heart to literally stop beating and obviously killing the infected animal (Voyles et al., 2009 and in other species that are entirely dependent on their skin to breathe such as Lungless Salamanders, it causes suffocation.
Both fortunately and unfortunately, not all Amphibians die from this fungal infection, with some species being “resistant” to the adverse effects and instead becoming carriers. These species in particular, such as the African Clawed Frog (Xenopus laevis), are of major concern to all Amphibians susceptible to the fungus Zoospores, due to being able to spread the infection further and cause further damage to other populations and of course cause extinction. In approximately only 30 years, Bd has caused the catastrophic decline or extinction (in many cases within a single year) of at least 200 species of frogs, even in pristine, remote habitats (Skerratt et al. 2007) some of them iconic such as the Australian Gastro-brooding Frogs (Rheobatrachus) and the neotropical Golden Toad (Incilius periglenes).
Conservation Efforts & Association Mitsinjo.
In Madagascar, some organisations are already well established, executing projects with already incredible results for the species in question. One of these organisations is Association Mitsinjo, a community-run conservation project which is situated in and around the small village of Andasibe, located within Eastern-central Madagascar. In is abundant is a vast amount of Anura, with approximately 100 species within a 30km radius of the town, 6 of these species are part of the incredibly beautiful Mantella genus.
As part of the Mitsinjo Amphibian Conservation Programme and Andasibe National Park, a breeding center (the Amphibian Survival Assurance Center of Andasibe) was constructed between the month of November 2010 to March 2011 to allow the captive breeding of certain species to be controlled and the successes to be monitored properly and information recorded for both behaviour and husbandry research. The facility itself is incredibly impressive measuring 185 square meters containing within it, completely bio secure rooms for various captive frog species, live food culturing, Research and even quarantine and isolation facilities, to prevent any potential risks to the already captive populations at Mitsinjo.
Conservation however, doesn’t necessarily have to involve breeding animals, it can also involve the simplest gesture, that is raising awareness and even in some case providing education. The Mitsinjo facility also includes an Educational Center which both foreign tourists and locals can visit to learn more about the work performed at the facility, the species found within the Andasibe Reserve and finally threats that affect all wildlife within the Nature Reserve.
Raising awareness for these small and fascinating frogs has even involved Mascots and Festivals dedicated to them, which tends to take place annually at a small village of Ampahitra. Last year, on the 25th of May the Mangabe Festival took place to raise awareness of the Golden Mantella (Mantella aurantiaca) at the protected site of Ranomena-Sahasarotra and has proved to be a successful attempt of trying to get the local communities around the reserve to engage and contribute towards both the habitats and the species that dwell in them. In this instance the Community organizations involved were rewarded for the efforts they carried out for the conservation of Mangabe’s forests from April 2012 to March 2013. This did include regular monitoring of the Golden Mantella breeding areas, the reporting illegal activities to the relevant authorities and even restoring areas degraded by slash-and-burn agriculture or gold mining.
Joshua S. Ralph