Biodiversity

Humans are part of a much wider web of life. How wide no one really knows. We have 'seen and named' between one and two million species, but researchers estimate that the total number of organisms on Earth is anywhere between ten and one hundred million - the margin of ignorance is extraordinary. Of course, most of these unknown species are pretty small - microbes, plants, fungi and invertebrates - but they are also the ones that do a lot of the work of keeping the Earth ticking over, cycling air, water and nutrients and trapping energy from the sun.

The IUCN (sometimes known as the World Conservation Union) Species Survival Programme says, 'The world's species face an unprecedented crisis. The rate at which they are being lost is alarming, even when compared with the [fifth] extinction episode of 70 million years ago when the dinosaurs disappeared. Recent calculations by leading scientists put it [the current extinction rate] at between 1,000 and 10,000 times greater than it would naturally be.'

In 2003 the World Conservation Monitoring Centre Red List showed that 12,000 species out of the 40,000 assessed, including 13 per cent of all flowering plants, faced extinction.

What is causing this crisis? In the last fifty years our numbers have doubled, leaving less room for other species. We are not managing our planet sustainably. Threats we are imposing that lead to loss of biodiversity include:

• habitat destruction
• climate change
• pollution
• disease
• urbanization
• agriculture
• overharvesting of economically/culturally valuable wild plants
• spread of alien invasive species knocking out the local species

The list goes on. Most of these threats are not intentional. They are by-products of the way we live. The rich nations consume, making the demands on the natural environment that cannot be met. The poor nations are forced to adopt lifestyles that also lead to the destruction of critical habitats.

Biodiversity loss is an issue to us because if it goes too far, despite the fact we are currently bucking the trend we will be among its first victims. An analogy sometimes used is that of a pilot who is flying along and notices that the rivets holding the wing together are falling out one by one. It's impossible to say with certainty how long you've got but you know it can't carry on.

Finding a way to live on Earth and meet our needs, while sustaining the richness of other life, is one of the most important challenges of the the twenty-first century. Eden's single most important messages to its visitors is to remind them of the myriad ways in which we depend on the natural world, every single second of every day, and to encourage people to reflect on what we need to do to sustain the world that sustains us.