The United Nations proclaimed May 22 The International Day for Biological Diversity (IDB) to increase understanding and awareness of biodiversity issues. Biodiversity is the degree of variation of life. This can refer to genetic variation, species variation, or ecosystem variation within an area, biome, or planet. Biologists most often define biodiversity as the “totality of genes, species, and ecosystems of a region”. The theme “Island Biodiversity” was chosen to coincide with the designation by the United Nations General Assembly of 2014 as the International Year of Small Island Developing States (SIDS).
Islands and their surrounding near-shore marine areas constitute unique ecosystems often comprising many plant and animal species that are endemic — that is to say, are found nowhere else on Earth. The legacy of a unique evolutionary history – these ecosystems are irreplaceable treasures. They are also key to the livelihood, economy, well-being and cultural identity of 600 million islanders—one-tenth of the world’s population.
Island Biodiversity – Why is it Important?
Many islanders are endowed with unique cultures and derive much of their economic, environmental and cultural well-being directly and indirectly from the rich natural resources in their immediate environment. Islands harbour numerous discrete ecosystems, from mountain forests to wetlands and beyond, that provide food, fresh water, wood, fibre, medicines, fuel, tools and other important raw materials, in addition to aesthetic, spiritual, educational and recreational values, that support island livelihoods, economies and cultures. Island ecosystems also contribute to the maintenance of ecosystem functions: they provide defence against natural disasters, support nutrient cycling, and soil and sand formation; and they contribute to the regulation of climate and diseases.
While much the same can be said of biodiversity in other settings, the components of biodiversity and the ecosystem services they provide is all the more critical on islands. Island economies, particularly those of Small Island Developing States (SIDS), are among the most vulnerable in the world because of the relative lack of economic alternatives available and such factors as:
- Small populations and economies,
- Weak institutional capacity in both the public and the private sector,
- Remoteness from international markets,
- Susceptibility to natural disasters and climate change (including in particular sea-level rise from climate change),
- Fragility of land and marine ecosystems,
- High cost of transportation,
- Limited diversification in production and exports,
- Dependence on international markets, export concentration, and income volatility,
- Vulnerability to exogenous economic shocks.
Aerial view of Marovo Lagoon, Solomon Islands. Credit: Convention on Biological Diversity
What is the problem?
The unique characteristics that make island biodiversity so special also leave it particularly fragile and vulnerable. Island species are present in relatively small numbers, making them very vulnerable to extinction. Furthermore, as island species have diminished dispersal capability and evolve in competition with relatively few other species, they develop survival strategies based on interdependency, co-evolution, and mutualism rather than defence mechanisms against a broad range of predators and competitors which arrived with human colonization in the form of cats, rats, mongoose, pigs, snakes and others.
Many island species have become rare or threatened, and islands have a disproportionate number of recorded species extinctions when compared to continental systems so that of the 724 recorded animal extinctions in the last 400 years, about half were of island species. At least 90% of the bird species that have become extinct in that period were island-dwellers, including the famous dodo. Over the past century, island biodiversity has been subject to intense pressure from:
- Invasive alien species,
- Tourism development,
- Climate change and variability,
- Natural disasters,
- Overexploitation and unsustainable uses,
- Pollution and waste disposal.
What needs to be done?
A number of international forums on sustainable development in recent years have outlined workplans to address the challenges faced by islands, particularly SIDS. Sustainable development is key to improving the economic, social and environmental resilience of islands. This will require increasing knowledge, techniques, data and information, plans and response strategies, technology, human resources development, community organisation and capacity-building, with the cooperation and assistance of the international community.
What can you do?
Read more about island biodiversity and check out the relevant facebook pages at https://www.facebook.com/BiodiversityDay and https://www.facebook.com/UNBiodiversity. Birdlife International runs a Preventing Extinctions Programme for critically endangered and endangered bird species, many of which are found on islands.
