Threats to Madagascar's biodiversity and ecosystems



Madagascar is among the world's poorest countries. As such, people's day-to-day survival is dependent upon natural resource use. Most Malagasy never have an option to become doctors, sports stars, factory workers, or secretaries; they must live off the land that surrounds them, making use of whatever resources they can find. Their poverty costs the country and the world through the loss of the island's endemic biodiversity.

Madagascar's major environmental problems include:

  1. Deforestation and habitat destruction.
  2. Agricultural fires.
  3. Erosion and soil degradation.
  4. Overexploitation of living resources including hunting and over-collection of species from the wild.
  5. Introduction of alien species.

DEFORESTATION

Deforestation in Madagascar is largely the result of three activities:
    Tavy or slash-and-burn agriculture

    Tavy is the lifeblood of Malagasy culture and the Malagasy economy. Tavy is mostly used for     converting tropical rainforests in Madagascar into rice fields. Typically, an acre or two of forest is cut, burned, and then planted with rice. After a year or two of production the field is left fallow for four to six years before the process is repeated. After two or three such cycles, the soil is exhausted of nutrients and the land is likely colonized by scrub vegetation or alien grasses. On slopes, the new vegetation is often insufficient to anchor soils, making erosion and landslides a problem.

    Tavy is the most expedient way for many Malagasy to provide for their families, and where day-to-day subsistence is a question there is little concern for the long-term consequences of the actions. From this perspective, as long as there is more forest land freely available for clearing, you might as well use the land before a neighbor does. Tavy for rice also has spiritual and cultural ties that transcend the economic and nutritional value of rice as a crop.

    Logging for timber

    Logging for timber is especially a problem in the rainforests of eastern Madagascar, particularly on the Masoala peninsula. The high value for Malagasy hardwoods (mostly ebony and rosewood, which may fetch $2,000 a ton in international markets) makes illegal logging a significant problem in some protected areas.

    Fuelwood and charcoal production

    The endemic spiny forests of Madagascar are being cut at an alarming rate for charcoal production. In eking out a living selling little piles of charcoal along roads in southwestern Madagascar, local people turn towards the nearest plant source, which in this case is often Alluaudia trees.

AGRICULTURAL FIRES

Every year as much as a third of Madagascar burns. Fires set for land-clearing and pastureland spread into adjacent wildlands, causing damage to the island's unique ecosystems.

EROSION

With its rivers running blood red and staining the surrounding Indian Ocean, astronauts have remarked that it looks like Madagascar is bleeding to death. This insightful observation highlights one of Madagascar's greatest environmental problems—soil erosion. Deforestation of Madagascar's central highlands, plus weathering from natural geologic and soil conditions, has resulted in widespread soil erosion, which in some areas may top 400 tons/ha per year. For Madagascar, a country that relies on agricultural production for the foundation of its economy, the loss of this soil is especially costly. more >>

OVEREXPLOITATION OF LIVING RESOURCES

Madagascar's native species have been aggressively hunted and collected by people desperately seeking to provide for their families. While it has been illegal to kill or keep lemurs as pets since 1964, lemurs are hunted today in areas where they are not protected by local taboos (fady). Tenrecs and carnivores are also widely hunted as a source of protein.

Reptiles and amphibians are enthusiastically collected for the international pet trade. Chameleons, geckos, snakes, and tortoises are the most targeted.

The waters around Madagascar serve as a rich fishery and are an important source of income for villagers. Unfortunately, fishing is poorly regulated. Foreign fishing boats encroach on artisanal fishing areas to the detriment of locals and the marine fauna. Sharks, sea cucumbers, and lobster may be harvested at increasingly unsustainable rates.

INTRODUCTION OF ALIEN SPECIES

The introduction of alien species has doomed many of Madagascar's endemic species. The best example of damage wrought by introduced species can be found in the island's rivers and lakes. Adaptable and aggressive tilapia, introduced as a food fish, have displaced the native cichlids.

There is really little use bemoaning past environmental degradation in Madagascar. Now the concern should be how to slow this ecological decline and how to best utilize lands already degraded so they support productive activities today and for future generations. Without improving the well-being of the average Malagasy, we cannot expect Madagascar's wildlands to persist as fully functional systems and continue to cater to the needs of their people.

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