The Conservation Of Madagascar And Its Lemurs Biology Essay
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The extraordinary island of Madagascar is unlike anywhere else on earth. Roughly the size of France, with an area of 226,658 square miles, it is the world's fourth largest island. It lies in the Indian Ocean, approximatly 250 miles off the coast of Southern Africa. Madagascar, and the tiny island of Comoro, provide the only present-day native habitat to lemurs (Butler, 2009).
"Nicknamed the 8th Continent" because of its diversity of species" (Hooper, 2005), Madagascar lacks the dominant form of primates distributed worldwide. Instead, their niche has been filled by an older group of primates, the Lemurs. Due to Madagascar's isolation, lemurs have an interesting evolutionary history.
Madagascar was originally "part of the super continent Gondwanaland. As Gondwanaland began to break apart around 160 million years ago, Madagascar broke away from Africa" (Carwardine, 2009). The Island continued to drift, moving away from Africa and by the evolution of monkeys, 17-23 million years ago, Madagascar was already isolated. As highly intelligent and adaptive primates, monkeys, quickly became the dominant primates around the rest of the world.
The Strepsirhini, the suborder that includes the lemurs, lorises, bushbabies, and pottos, were driven away and towards extinction by these advanced primates. The lorises, bushbabies, and pottos were able to relatively successfully coexist with the monkeys, largely due to their nocturnal and insectivorous traits. They did not compete with the monkeys; however, the lemur lineage was driven to find a new home, Madagascar (Baines, 1997).
As the island of Madagascar drifted futher from Africa, the lemurs were then isolated from the rest of the world and its evolutionary changes. They are now "By far the most renowned and diverse group of Madagascar's mammals" (Sauther, 2009). They have spread throughout Madagascar, filling the niches without much competition or predators. Today lemurs are found in "almost all of the ecosystems of Madagascar" (Carwardine, 2009), many have adapted in amazing and bizarre ways to ensure their survival.
Higher primates or homo-sapiens did not reach Madagascar until around 2,000 years ago, when they learned to navigate the seas (Oldfield, 2002). Once there, humans began to systematically destroy the previously untouched island .15 species of lemur are known to have become be extinct, but many more are thought to have disappeared before they were even discovered. Currently all lemurs are in danger, largely due to habitat destruction and hunting.
Madagascar's terrain is as diverse as its wildlife with coastal plains, mountain ranges, dramatic escarpments, and dense rainforest. As such, there is a great diversity of ecosystems, each with differing vegetation and therefore: different species. This is usually in accordance with relief, geology and rainfall.
The first humans to arrive on Madagascar were the ancestors of the Sakalava people, who originated in Indonesia and now live in the West of the island. These early settlers practiced shifting cultivation, burning the previously untouched vegetation. In the 9th and 13th centuries respectively, the ancestors of the Merina people and Betsileo tribes of Northern Madagascar also arrived from Indonesia, and began farming rice. During the last 1,200 years people from Africa and the Arabian Peninsular have also settled in Madagascar, bringing with them Zebu cattle. Many traditional ceremonies and rituals are based around Zebu cattle, even today many Madagascians measure their wealth by the number of Zebu they own. As such there is now more Zebu than people on Madagascar. Every year vast areas of vegetation are burnt in an attempt to improve pasture for these animals (Oldfield, 2002).
In 1895 Madagascar became a French colony. These new settlers "began harvesting valuable hardwoods for export, such as ebonies and rosewoods, the harvesting of these trees continues today. The endangered Dalbergia delphinensis tree is one of over 30 rosewoods threatened due to selective felling" (Oldfield, 2009). The restricted distribution of this species also coincides with a "proposed site for a titanium mine which threatens all the remaining coastal forest in Southeast Madagascar" (Kimball, 2009). Also to it's detriment, Madagascar's rainforests contain valuable minerals, such as gold and sapphires. Attempts to extract these poses further threats.
Mining is one of the many threats to Madagascar's forests and the many species that rely on them. Wood is also cut for fuel and many logging companies are keen to acquire forest concessions. Another threat is the local form of shifting cultivation known as tavy. Most of Madagascar's 13 million human inhabitants depend on the land for their livelihood. Massive amounts of forest are cleared every year by cut and burn techniques for rice cultivation, maize and cassava. Many areas are exhausted of their nutrients and then abandoned, the secondary vegetation that then grows is known as savoka, this is eventually replaced by grassland (Oldfield, 2002).
Madagascar is home to a massive 10,000 or so plant species, 80% of which are endemic to the island (Carwardine, 2009). Although Madagascar's animal diversity is less striking, many species are unique to the island. "Over 250 bird species, nearly half of which are endemic to the island, 300 species of reptiles, over 90% of which are found only on Madagascar" (Oldfield, 2002). The islands only amphibians, 178 frog species, all of which are endemic and more than 33 known species of lemur inhabit Madagascar, more than half in its depleting rainforests. According to the Botanist, Henri Perrier de la Bathie, writng in 1921, "The once mighty rainforests of Madagascar have declined dramatically. As early as 1921, felling had destroyed ninety per cent of Madagascar's forests" (Sauther, 2006 ).
Biologically, "it is regarded as one of the richest areas on the planet" (Green, 1990), however, no one has ever managed to make a full evaluation of Madagascar's many threatened rainforest species. Conservation-status information on some species of animals and trees has been assembled, but is nowhere near complete. Of the rainforest species of lemurs alone, threatened species include the Indri, as well as the Aye-aye, Hairy-eared Dwarf Lemur, Golden Bamboo Lemur and the Red-bellied Lemur.
According to Ian Tattershal in Michelle Sauthers report, Lemurs: Ecology and Adaptations, "there is general agreement that the lemurs, including the recently extinct subfossil forms, should be classified into seven families: Cheirogaleidae, the dwarf lemurs with five living genera; Lemuridae, the true lemurs and their close relatives, with five genera (one extinct); Lepilemuridae, with two genera (one extinct); Indriidae, with three living genera, Archaeolemuridae, with two genera (both extinct); Palaeopropithecidae, with four genera (all extinct) and Daubentoniidae, the aye-ayes, with a single living genus and species."
Depending on whose classification is accepted, living lemurs may number up to forty different species and possibly even up to seventy two species, if subspecies are included in the count. With these numbers, and despite recent extinctions, Madagascar "ranks third highest on the list of high-primate diversity countries worldwide" (Sauther, 2009), despite being only one tenth of the size of the world leader, Brazil.
All of these species of lemur are endemic to Madagascar. According to the ICUN Red List of Threatened Species, each of these species has different threats to their survival. Many lemurs, such as the Red-ruffed Lemur, and many types of bamboo lemurs are critically endangered. With a drastically reduced habitat there are few left in the wild. The Hairy-eared Dwarf Lemur, Golden-brown Mouse Lemur, and the Black and White Ruffed Lemurs are not as close to extinction, but are listed as endangered. Some of the lemurs listed as vulnerable include the Black Lemur, Crowned Lemur, and a number of Fork-marked Lemurs. Perhaps the most remarkable lemur species have long been extinct. These included the Archaeoindris, which was larger than an adult male gorilla, the Babakotia and the Magaladapsis.
All lemurs are protected by law, and in many communities it is considered taboo to kill an Indri, but elsewhere, the Indri, and many other species of lemur, are hunted for food and sometimes sold as bush meat or pets (Carwardne, 2009).
Madagascar has suffered environmental degradation over a significant part of its land mass. Once covered with rainforests, most of the Eastern third of Madagascar is now, either barren, or reduced to shrub land. As indigenous vegetation is cut and burned for fuel many areas such as the Spiny forest, which contains many rare plant and animal species endemic to the island, have given way to cactus scrub. "Around eighty per cent of the original plant cover has been destroyed and much of the terrain is now degraded grassland" (Oldfield, 2002).
Each year, a further 1% of Madagascar's forests are levelled. This mass deforestation not only affects the land and its inhabitants directly, but also indirectly. Without vegetation to absorb moisture the soil is eroding away at an alarming rate. Enviromental regulations have been in place to protect the forests and species of Madagascar since 1881 and at present, more money is put towards the conservation of Madagascar, than any other part of Africa (Butler, 2009).
Madagascar is one of the world's poorest nations, with a per capita income of approximately $240 per year. About 80 percent of the population are subsistence farmers, many of whom depend entirely on "natural capital" to support their way of life. The people's dependency on the land and natural resources is of major consequence to Madagascar's ecosystems and endemic biodiversity (Kremen, 2010).
The major environmental problems of Madagascar include deforestation, and thus loss of habitat, agricultural fires, erosion and soil degradation and the over exploitation of resources.
The deforestation of Madagascar can be mostly attributed to three activities. Tavy, or slash and burn agriculture, logging for timber, and fuel wood and charcoal production. "Tavy is a large part of Malagasy culture, and has been since the arrival of humans on the island. It is used to convert tropical rainforest into rice fields. An acre or two of land may be cut or burned; it is then planted with rice. After several years production the land is then left fallow for up to six years before replanting" (Kremen, 2010). After several of these cycles the land is exhausted of all its nutrients and no primary vegetation will grow. The land then becomes barren and only scrubs and a few grasses will grow. This vegetation is often insufficient to anchor the soil, especially on slopes, making erosion a problem.
According to the ICUN, "the high value of Malagasy hardwoods also makes logging for timber a significant problem in many areas of Madagascar, especially in the rainforests of Eastern Madagascar". Even the few areas that are protected are often illegally logged and even the endemic spiny forests of Madagascar are being cut at an alarming rate for charcoal and fuelwood production. Every year, as much as a third of what remains of Madagascar's forest burn. Fires set for land clearing and pastureland often spread into adjoining forests ,causing much damage and further reducing the habitat of many species of flora and fauna.
For Madagascar, a country that relies on agricultural production as the foundation of its economy, the loss of this soil, due to erosion, is a massive problem. The deforestation of Madagascar's central highlands plus weathering has resulted in massive soil erosion accounting for up to 400 tons per year. Every yea,r the cost of environmental damage is approximated to between 100 and 290 billion US dollars. Deforestation represents 75% of this loss and 15% due to the erosion that effects agricultural and pastoral production (Oldfield, 2002).
Due to the factors mentioned throughout, and many more, Madagascar's species are among the most threatened in the world. Since the arrival of man Madagascar has lost a known 16 species of lemur, including one the size of a gorilla; a pygmy hippo, the largest land bird to ever walk the planet, and giant tortoises, a species that had survived for 200 million years. The ICUN Redlist currently includes 472 Malagasy species at risk of becoming extinct, although this number is probably massively optimistic. Today, Madagascar is arguably the world's highest conservation priority (ICUN, 2011).
Ensuring the survival of lemurs is not only important because they are endemic to Madagascar, but also because they benefit plants and other animals. Many species of lemur are very important seed dispersers for forest trees and pollinators for many of the plants that are also endemic to Madagascar. They are also an important source of food for other animals.
The National Association for the Management of Protected Areas in Madagascar (ANGAP) was founded in 1990 to manage Madagascar's protected areas system. ANGAP's mission is to safeguard Madagascar's ecosystem, research the potential of Madagascar's biodiversity, develop environmental education programs for local people, promote potential commercial applications of Madagascar's biodiversity, for example ecotourism, and to support sustainable development activities in areas surrounding protected zones. One of ANGAP's goals is to enable local communities to directly benefit from the conservation of Madagascar. Half of the entrance fees to the conservation parks go directly to local communities and visitors can not enter a park without hiring a local guide. ANGAP also works closely with many other organisations and scientists to asses the impact of visitors to the parks and reserves and study the biodiversity of Madagascar. The ANGAP manages the protected areas network in Madagascar (Butler, 2009).
The network includes three types of protected area. Strict nature reserves, national parks, and wildlife reserves. In 2003, at the ICUN's world parks congress, Marc Ravalomanana, the Malagasy president, announced a bold plan to expand the amount of area under protection from approximately 1.7 million hectares to over 6 million hectares. In 2005 the first 10,000 km2 of the new protected areas system of Madagascar was granted protection status and in 2006 1 million hectares was added, both contributing to the overall goal of 10% of Madagascar being protected. This plan also involved broadening the definition of protected areas in Madagascar and legislation has since been passed to allow four new categories of protected area, natural parks, natural monuments, protected landscapes, and national resource reserves (Butler, 2009). Madagascar currently has 19 terrestrial national parks, 2 marine national parks, 5 complete natural reserves, and 21 special reserves.
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