Western Indian Ocean Islands and biodiversity

Overview of resources

caption Table 1: The biodiversity features of WIO islands
(Source: Groombridge and Jenkins 2002, Hoekstra and others 2005, Mayaux and others 2004 and WRI 2005)

The Western Indian Ocean (WIO) islands are characterized by significant plant endemism as well as other biodiversity, which is related to their island status. These islands are among the most globally important priorities for conservation, mainly due to the outstanding levels of endemism.

Madagascar has been separated from the African mainland and from India for millions of years. As a consequence, most of the plant and animal species present there have evolved in long isolation. Madagascar’s most striking feature is its exceptionally high endemism in nearly all groups, particularly at the generic and family levels. Many groups also show very high levels of species diversity on Madagascar. Plant species richness is currently estimated to be at least 12,000 species, and possibly as many as 14,000, of which more than 90 percent are endemic. Among vertebrates, the extant mammal fauna comprises 101 native terrestrial species, none of which is found anywhere else on Earth.

By contrast, the other Indian Ocean islands are composed of relatively recent volcanic islands (the Mascarenes and the Comoros) or fragments of older continental material (the main group of the Seychelles). They are biologically closely linked to Madagascar, and reveal important endemic biodiversity. They add important endemic biodiversity for the total land area of 590,000 km2 (including the Iles Esparses, a series of small French-held islands surrounding Madagascar: Les Glorieuses, Juan de Nova, Tromlin and Bassas da India).

The Mascarenes have about 1,300 vascular plant species, of which 585 are endemics, the Comoros have about 1,000 species (150 endemic), and there are about 310 species in the Seychelles of which 75 are endemic. Madagascar and its neighbouring island groups have a total of eight endemic plant families (with seven families endemic to Madagascar and one to the Seychelles), four endemic bird families, and five endemic primate families.

Opportunities for development

The rich biodiversity most of the WIO countries forms a significant natural resource base that provides valuable raw materials for local and commercial use. It is important for tourism, food, construction and shelter. In addition, many plant species are used medicinally and several species are being researched for commercial agricultural or pharmaceutical use. Management of these species, which offer social and economic opportunities for development, plus the management of other threatened species, are features of environmental policy and programmes in the WIO islands.

The 4 million km2 of the WIO Exclusive Economic Zone (EEZ) has offered in the past, the opportunity for economic development through deep-sea fishing, but the stocks are now probably exploited to their upper limit. Biological and ecological research and the evaluation of tuna stocks have emerged in the past decade as major fields for conservation studies. These cover oceanographic and environmental aspects that impact on tuna catches, including conventional and electronic tagging for monitoring migration, numbers and size of species, for scientific and commercial purposes. A regional project on aromatic and medicinal plants has provided an inventory of more than 600 species within the member countries, used in traditional practice, as a basis for further scientific and commercial study and development.

Challenges faced in realizing opportunities for development

caption Mirza zaza, a new lemur species, discovered in Madagascar in 2005.
(Source: D Haring/Duke University Primate Center)

Coastal and marine habitat loss threatens the survival of animal and plant species, and thus undermines livelihood and development options. As small island developing states (SIDS) the WIO islands experience many of the same problems, often linked to tourism, coastal livelihoods and overfishing, waste management, and a high level of vulnerability to natural disasters and humaninduced environmental change. Important drivers of and pressures contributing to environmental change include: unsustainable natural resource exploitation, habitat conversion and destruction, the introduction of invasive alien species (IAS), pollution and soil degradation, coastal erosion, seawater intrusion, bush fires, overfishing in lagoons, long line and fine net fishing, coastal urban tourist development, building on wetlands, water pollution, land reclamation with its degradation of lagoons and coral reefs, sand mining in lagoons, islets and coastal areas, hunting, inadequate management of waste and intensive farming.

Loss of forest cover inland, in particular in upland zones, and the adverse impact of IAS, threaten the survival of endemic species. Freshwater ecosystems have been seriously impacted by IAS such as Eichornia crassipes (water hyacinth). Alien domestic animals, such as cattle, sheep and goats, have caused important changes in native plant communities and have helped drive many endemic terrestrial herbivores to the brink of extinction. Human activities are thought to be primarily responsible for the current pattern of vegetation change: grassland wildfires set by herders either to stimulate regrowth during the dry season or to eliminate unpalatable herbaceous species, and forest clearing for agriculture, timber and charcoal production.

In the Comoros, up to 7 percent of the land has become deforested, and patterns of rainfall and drainage have also changed. The main threats to natural habitats in Madagascar and the Comoros are forest loss through slash-and-burn agriculture and fire, with logging and mining on the rise in Madagascar. In Mauritius and the Seychelles, conversion of land for housing and other uses presents the biggest threat.

These factors adversely affect biodiversity and terrestrial and marine ecosystems, including seagrasses, mangroves and the coral reefs. The prospects for the conservation of rare animal species such as the wandering albatross, turtles, coelacanth, the Mascarene black petrel, the pink pigeon and others, critically depend upon the transformation and scaling-up of intervention from small scientific projects to major mainstream programmes.

Strategies to enhance opportunities for development

Interventions at a national and sub-regional level are important.

There is a need for developing policy-relevant environmental performance indicators for biodiversity. In addition, the identification of sustainable development goals and objectives, with clear objective verifiable indicators, the identification of lead agencies for implementation and results-based budgeting are important planning tools. Greater technical assessment of the most appropriate means of extending pilot and project work into mainstream programmes is also needed. The work of the subregional bodies, such as the Indian Ocean Commission (IOC), indicates how this technical aspect of work can be taken forward, in concert with that being established in other regions with large numbers of islands states, such as the Pacific and the Caribbean.

Regional support is also essential in human resource programmes, especially for professional, technical and managerial development (UN 2005).

At the national level, establishing protected areas is seen as a key strategy for protecting biodiversity.

Considerable progress has been made in Madagascar, where there has been renewed political commitment to conservation. In 2003, at the World Parks Congress in Durban, South Africa, Madagascar declared its intention to triple the total land area managed for conservation purposes. More recently, during the International Scientific Conference on “Biodiversity, Science and Governance”, held in Paris in January 2005, the intention was reiterated and the objective of biodiversity protection was confirmed to be an essential element in decreasing poverty and increasing opportunities. Collaboration at multiple levels supports this. Government, in collaboration with scientists and conservationists, is identifying priority areas for conservation. Additionally, a multidisciplinary group of non-governmental organizations (NGOs) is collaborating with the government in identifying potential priority sites for conservation, the legal aspects of implementing management plans, and the adoption of the World Conservation Union (IUCN) protected area categories. By 2002, Madagascar’s protected areas network included 46 sites covering between 2 percent and 2.7 percent of the country’s total surface. Current approaches for area selection are based on biological collections and on a range of eco-geographic parameters. Thus both large and small areas with unique biodiversity have been identified for protection. During the process of identifying priority conservation areas, scientists identified important data gaps, particularly regarding marine, freshwater and mangrove environments, and also non-vascular plants. Rules have been adopted for a conservation management system that gives the local community an important role. The newly designated conservation sites will operate based on some improved management principles: more dynamic and flexible management will be encouraged than the current system which over-relies on non-use measures.

The Seychelles have about 208 km2 of national parks, in varying degrees of implementation. Taken together, all parks, irrespective of the degree of protection, represent about 42 percent of the land area. There are a further 228 km2 of marine national parks. In Mauritius, there are ten protected areas within the IUCN categories I – II, with a total area of 70 km2. In addition there are 90 km2 of marine protected areas. In the Seychelles and Mauritius, which are economically better off than Madagascar, the factors threatening biodiversity differ substantially from those in Madagascar. Conservation strategies in Mauritius place less emphasis on rural development and poverty alleviation, and more on the political process leading to the establishment of protected areas and improved land-use planning.

In the Comoros, the situation has more in common with Madagascar. There are three protected areas covering 400 km2, which represents 24.3 percent of the total land area. Although levels of diversity and endemism are more modest in the Comoros, biodiversity conservation is nevertheless a high priority. In this context, the approach developed in Madagascar, in which carefully compiled and analysed data are being used to inform the process of identifying new conservation sites, could serve as a valuable model. The principal challenge for the next decade is to convert these projects into mainstream programmes and sustain and improve on the results already achieved. This will depend on long-term political, financial and management support, together with the development of professional and technical services on a local, national and sub-regional basis. Special emphasis is needed in these programmes to link the protection of the environment to the relief of poverty, community and professional education, and the sustained use of natural resources for the benefit of social and economic development at community level. This process of transformation is also vital for continued development of programmes more directly linked to commercial development which depend upon the survival of species used in agriculture, forestry and fisheries, for food, medicine, industry and in the promotion of eco- and educational tourism.

Further reading

  • Dewar, R.E., 1997. Were people responsible for the extinction of Madagascar’s subfossils, and how will we ever know? In Natural Change and Human Impact in Madagascar (eds. Goodman, S.M. and Patterson, D.), pp 364-77. Smithsonian Books, Washington, D.C.
  • Goodman, S.M. and Benstead, J.P. (eds. 2003). The Natural History of Madagascar. University of Chicago Press, Chicago.
  • Government of Mauritius, 2005. Mauritius – Staking out the Future. Ministry of Environment and national Development Unit, Port Louis.
  • IOC, 2004a. AIMS Synthesis Report, progress on the Barbados Programme of Action. Indian Ocean Commission for the AIMS Group, Port Louis.
  • Kull, C.A., 2000. Isle of fire:The political ecology of grassland and woodland burning in highland Madagascar. Ph.D. thesis. University of California, Berkley.
  • IOC, 2004b. Report on Implementation of Barbados Programme of Action,Annex 2. Indian Ocean Commission, Port Louis.
  • Langrand, O. and Goodman, S.M., 1995. Monitoring Madagascar’s Ecosystem :A Look at the Past, Present and the Future of its Wetlands. In Ecosystem Monitoring and Protected Areas (eds. Herman,T.B., Bon-Drup-Nielsen, S.,Willison, J.H.M. and Munro, N.W.P.), pp. 204-14. Sciences and Management of Protected Areas Association, Wolfville.
  • Louette, M., Meirte, D. and Jocque, R., 2004. La faune terrestre de l’archipel des Comores. Sciences Zoologiques, No. 293. Musée Royal de l’Afrique Centrale,Tervuren.
  • Lowry, II P.P., Schatz, G.E. and Phillipson, P.B., 1997. The Classification of Natural and Antropogenic Vegetation in Madagascar. In Natural Change and Human Impact in Madagascar (eds. Goodman, S.M. and Patterson, B.D.), pp 93-123. Smithsonian Books, Washington, D.C.
  • Mittermeier, R. A., Gil, P. R., Hoffman, M., Pilgrim, J., Brooks, T., Mittermeier, C.G., Lamoreux and da Fonseca, G.A.B., 2004. Hotspots Revisited: Earth’s Biologically Richest and Most Endangered Terrestrial Ecoregions. CEMEX Books on Nature Series. CEMEX, Mexico City.
  • National Research Council – Committee on the Formation of the National Biological Survey, 1993. A Biological Survey for the Nation. National Academy Press,Washington, D.C.
  • Randrianandianina, B.N., Andriamahaly, L.R., Harisoa, F.M. and Nicoll, M.E., 2004. The Role of the Protected Areas in the Management of the Island’s Biodiversity. In The Natural History of Madagascar (eds. Goodman S.M. and Benstead, J.P.), pp 1423-32. The University of Chicago Press, Chicago.
  • Republic of Seychelles, 2004. National Assessment of the Barbados Plan of Action +10 Review.
  • Republic of Seychelles, 2000. Environment Management Plan 2000-2010: Managing for Sustainability. Ministry of Environment and Natural Resources, Mahé.
  • Robertson, D.P. and Hull, R.B., 2001. Beyond biology: toward a more public ecology for conservation. Conservation Biology. 15, 970-9.
  • UNEP, 2005a. Atlantic and Indian Oceans Environment Outlook, Special Edition for the Mauritius International Meeting for the 10-year Review of the Barbados Programme of Action. United Nations Environment Outlook, Nairobi.
  • UNEP, 2006. Africa Environment Outlook 2.



This is a chapter from Africa Environment Outlook 2: Our Environment, Our Wealth (e-book).
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Programme, U. (2007). Western Indian Ocean Islands and biodiversity. Retrieved from http://www.eoearth.org/view/article/157067

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