A day and year for biodiversity

22 May 2009

Today is the International Day for Biological Diversity (IDB). Each year on 22 May, organisations and countries who’ve signed up to the UN's Convention on Biological Diversity (CBD), can raise awareness of different biodiversity themes.

The theme this year is invasive alien species, which are one of the greatest threats to the Earth’s biodiversity. They also have huge economic costs to human activities such as agriculture, forestry and fishing.

Biodiversity is the focus for the whole of next year too as 2010 is the International Year of Biodiversity (IYB). Many organisations, including the Natural History Museum, are taking part in a year of events to celebrate the planet's diversity.

Invasive alien species

Plants, animals and other organisms that are not native to the environment they are in, are alien species. They become invasive when they establish themselves, and start having an adverse effect on the native species or the local environment.

Introduced species

Species can be introduced into new areas in many ways and most are accidental. For example, the ant, Lasius neglectus from western Asia has made its way to the UK in imported soil and plants. It has supercolonies up to 100 times bigger than the common UK garden ant.

Becoming established

Different factors affect how a new species becomes established. Often they have no natural predator in their new environment and so can quickly increase in numbers.

Social behaviour can influence an alien species' success too. The queen of the supercolony ants mates within its own colony, unlike most other ant species that leave the colony and search for new ants and nests elsewhere.

Climate change can make areas that were previously unsuitable, suitable to an alien species. A succession of mild UK winters has increased the survival rate of a number of creatures that would more normally die off in cold winters, such as the non-native false widow spider, Steatoda nobilis. It has increased steadily along the south coast over the last 15 years.


Invasive alien species may out-compete, or prey on, the native species, or introduce new diseases. They can also change their surroundings, for example, mitten crabs originally from China burrow into and damage riverbanks of the River Thames.

Museum collections

The Convention on Biological Diversity states that there could be around 13 million species of plants, animals and organisms living on Earth. The Museum’s 70 million specimens are crucial in helping scientists to identify and classify one species from another, a process called taxonomy.

Museum research

Once identified, scientists can also assess whether a species is likely to become invasive and they can work out ways of controlling the impact of pests in an environmentally friendly way.

For example, accidentally introduced whiteflies in the Canary Islands had grown to enormous numbers. They were leaving nasty deposits on benches, cars and laundry and even caused asthmatic attacks in some locals. Museum research identified where the whiteflies came from and that their natural predator was a parasitic wasp. The wasp was then introduced to help naturally control whitefly numbers.

Sometimes there are commercial solutions too. Museum research on the Chinese mitten crabs living in the River Thames have found them safe for humans to eat. So they could be farmed and sold to the local crab meat trade.

Why conserve biodiversity

Biodiversity is the variety of life on Earth, from micro-organisms to mighty whales, along with the habitats they depend upon.

Many basic natural services, such as fresh water, fertile soil and clean air are supported by biodiversity, as well as flower and crop pollination, waste removal and much more.

No one organism lives in isolation. The millions of organisms on Earth that interact with each other contributes to the balance of the global ecosystem and the overall survival of the planet.

Humans depend on the variety of the living world for their well being and the natural world is dependent on us to take steps to conserve biodiversity before it's too late.

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Further information

  • Find out more about the International Year of Biodiversity

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