THE Earth supports five to ten million species, of which only 1.75 million have been categorised in any great detail. However, many species of animals and plants are under threat from habitat loss, pollution, changes in weather and unsustainable use of resources by humans.
The 2005 Millennium Ecosystem Assessment estimates that by the end of this century climate change will be the main driving force of biodiversity loss. We must never forget that this loss is not purely a matter of sentimentality or aesthetic appreciation.
Loss of biodiversity and destruction of fragile ecosystems are being felt across the world already. This has intensified over the last few decades and loss of ecosystems is fast becoming an existential threat, exacerbating problems of population growth, food security and climate change.
Today's population of 6.8 billion is estimated to reach around nine billion by the middle of the century. Yet of the 7,000 plant species that have been cultivated for food since agriculture began 12,000 years ago we only use about 15 plant and eight animal species to supply 90 per cent of our food.
Ecosystems provide valuable services necessary for human well-being; such wood for fuel, water purification and food production; many of which we are using unsustainably.
But there are many other less obvious services we depend on. Ecosystems provide supporting services like nutrient cycling, oxygen production and soil formation. All these are vital if we are to feed our growing population without further degrading our environment.
Climate change is taking its toll, primarily through changes in rainfall and temperatures.
Some species will not be able to keep up with the pace of change and will simply die out. Flooding sea level rises and changes in temperature are also likely to trigger substantial changes in the structure and functioning of all ecosystems.
Complex maritime ecosystems such as coral reefs are suffering losses due to higher water temperatures. Higher temperatures will also have an effect on the geographical dispersal of species and change reproduction timings.
The equilibrium of ecosystems in this country could become unbalanced if insect pests previously unknown in Britain are able to survive warmer winters. At the moment invasive non-native species are the second greatest threat to biodiversity in the UK after climate change.
Another problem closer to home is the phenomenon known as Colony Collapse Disorder. Seemingly healthy honey bee colonies have been going into steep decline since its identification in 2006. This decline is a cause of deep concern. Many crops are highly dependent on honey bees as pollinators.
Fortunately, governments have recognised the harmful impact this is having on food production and has put £10 million into a research programme and a dedicated Bee Unit at the Food and Environment Research Agency.
But it is the poorest people in the developing world, despite contributing less to the emission of pollutants and carbon, who suffer most from the impact of climate change.
Many of these countries lie in regions most at risk from changes in weather and these people usually depend heavily on climate-sensitive sectors like fishing and agriculture.
A UN-sponsored ecosystems report calculated that environmental degradation is costing $2-5 trillion per year, mainly in the poorest parts of the world.
But all is not lost. There is research to suggest that conservation efforts made across the globe are having a noticeable effect.
Biodiversity conservation and the maintenance of ecosystem integrity are central to improving the ability of the poor to cope with climate change.
Ecosystems that are filled with a variety of unique ecological roles are more stable and usually better able to adapt to climate change than impoverished systems.
For example. genetic diversity can be used as part of the climate change adaptation process. Wild relatives of food crops can be used to breed new varieties that can cope with changing weather conditions.
But as well as being victims of climate change, properly functioning ecosystems can also help mitigate the effects of climate change. Ecosystems like salt marches can provide a cleaning function by absorbing nutrients, heavy metals and oil from estuary systems and also have an increasingly important role in coastal protection against erosion.
Salt marshes are a cost-effective way in the long run to protect coastal areas from extreme weather conditions like tidal surges and floods.
Loss of biodiversity has added a new dimension to the climate change debate and how we can cope in the future. Biodiversity is not just suffering from our changing climate; its loss is also making it harder for us to deal with the challenges ahead.
This is the official Year of Biodiversity, and as I write this, delegates at the UN Biodiversity Convention in Japan are setting out new targets to reduce biodiversity loss. This is certainly a step in the right direction.
We have the scientific knowledge necessary to tackle biodiversity loss; now let's get on and do something about it.
Source: This is Exeter [November 05, 2010]