What Is Biodiversity?

Biodiversity is the measure of variety of the Earth's animal, plant and microbial species; of genetic differences within species and of the ecosystems that support those species.

The term first came to public attention in 1992 at the Rio Earth Summit at which a convention for the preservation for the maintenance of biodiversity was signed by over 100 world leaders [excluding the USA as they feared it would undermine the patents and licences of US biotechnology companies]

The maintenance of biodiversity is important for ecological stability and maintaining the gene pool, and as a resource for research into, for example, new drugs and crops

What is causing a reduction in biodiversity in both the developed [EDC] and less developed [ELDC] worlds?

Most of the threats currently faced by species of plants and animals are linked to human action. In some cases this action, for example, hunting, deliberately aims to reduce species numbers[ e.g. White Rhino-sole purpose of which is to cut the horn off for illegal sale to Asian (mainly China) who mistakenly believe it has aphrodisiac powers]. There few Rhinos left and some subspecies have disappeared altogether e.g. Javan and Sumatran. Similar fate is facing the tiger e.g. Bengal down to 1,500 in number, Siberian circa 250 left.

In other situations species are inadvertently affected, for example, where habitats are destroyed or modified by people wishing to use the land for other purposes [For example , Korean Hyundai Company has just been given concession for deforestation and mineral exploration in key Siberian Tiger territory].

In extreme cases, a species may become extinct- this is irreversible- a loss of biodiversity. Extinction in the wild means that some individuals may still exist in captivity or in a seed bank. Extirpation is localized loss.

Habitat destruction and modification is the most serious threat to biodiversity. Some indication of the extent of this problem is given in the table below:

COUNTRY FOREST %LOSS GRASSLAND % LOSS WETLAND/MARSH % LOSS

ETHIOPIA 85 60 0

FRANCE 99 NO DATA NO DATA

MALAYSIA 42 0 35

NAMIBIA 50 60 10

THAILAND 73 0 96

The reasons for human action are well known- land cleared for farming, herding, settlement and industry. Although much attention has been focused on the biologically rich ecosystems such as rainforests, coral reefs and mangrove swamps, widespread alterations have already occurred in the habitats of temperate latitudes such as in the UK.

In the UK, farmland occupies 72% of the [present land area. 5000 years ago, UK was almost entirely covered in forest. Today, the Uk is 0ne of the least wooded countries in Europe. [8% land cover in England and Wales- most of this is recent conifer planting]; land covered by ancient woodland e.g. oak/beech/ash/elm is 2.5%.

There are many examples of species driven to edge of extinction because of habitat destruction. Possibly the best known is the Giant Panda, once found all over China, now confined to a few sites near the city of Chengtu in the Province of Szechwan in western China. The giant panda relies heavily on a diet of bamboo but China's bamboo forests have been converted to farmland. Despite conservation attempts by WWWF [World Wide Fund for Nature (panda emblem)] and breeding programmes in zoos [largely unsuccessful], genetic biodiversity so reduced that species will probably die out.

Fragmented destruction of habitats as well as total destruction can also bring about reductions in biodiversity by reducing the chances of normal dispersion and colonization processes of species and reduces areas for foraging

Hunting

People have been responsible for the extinction of species through hunting for food for a long time. Such affects can be traced back to the Stone Age. The loss of large mammals such as the mammoth and sabre toothed tiger has been linked to over hunting.

Large animals which are easy to see coupled with the use of a firearm enhanced out ability to exterminate species in large numbers. For example in the USA the passenger pigeon declined to the point of extinction by