29. Loss of Biodiversity
CHAPTER 29: LOSS OF BIODIVERSITY - INTRODUCTION
The Earth's genes, species, and ecosystems are the product of over 3000 million years of evolution, and are the basis for the survival of our own species. Biological diversity (often shortened to 'biodiversity') is a measure of the variation in genes, species and ecosystems. It is valuable because:
* diversity is the base of the stability and sustainable functions of natural systems;
* of its enormously wide range for potential and unexplored uses;
* here there is evidence that a removal of ecosystem components can have negative impacts; and
* variety is inherently interesting and more attractive.
Chapter 9 attempts to give a first broad assessment of nature and wildlife on a pan-European scale by examining the state and distribution of ecosystems and species.
A large variety of European landscapes, described in Chapter 8, forms the ecological base for a number of semi-natural habitats for many species of flora and fauna. By encompassing also many important natural habitats (relatively untouched areas), European ecosystems are composed of more than 2500 habitat types (according to the CORINE Habitat Classification) (CEC, 1991) and include about 215 000 species, of which more than 90 per cent are invertebrates (animals without backbones).
Worldwide, about 1.4 million living species of all kinds of organisms have already been scientifically catalogued, but it is estimated that the actual number might be 20 to 30 times higher. Of the 1.4 million classified thus far, approximately 750 000 are insects, 40 000 are vertebrates and 250 000 are vascular plants and bryophytes (eg, mosses) (Parker, 1982). The remainder consists of a complex array of invertebrates, fungi, algae and microorganisms. Each species is the repository of an immense amount of genetic information. The number of genes range from about 1000 in bacteria and 10 000 in some fungi to 400 000 or more in many flowering plants and also in some animals (Hinegardner, 1976).
Although Europe appears to feature a rather modest range of flora and fauna, biodiversity is not defined by number alone. Each biogeographic region of the world has a different and typical set of environmental conditions and its own equilibrium or optimum. Hence, for example, it is impossible to base qualitative assessment of an oligotrophic bog in Ireland on the number of species: this highly specialised habitat is naturally poor in species, and species richness would indicate the presence of a 'sub-optimal' habitat condition probably due to eutrophication.
This example illustrates that biodiversity cannot be understood soley by comparing species; the 'optimal' state of individual habitats and their naturally occurring species must also be taken into account. Such a definition makes biodiversity as much a crucial principle of oligotrophic bogs as of tropical rainforests.
Within Europe, the distribution of species and ecosystems is widely variable, with the least richness found in the far north. Centres of biodiversity are found in the Mediterranean basin and on the margins of Europe in the Caucasus Mountains (Ukraine, Georgia, Armenia), with about 5000 plants being endemic to individual countries. Almost every European country has endemic species (that is, species found nowhere else), but many other species are found in more than one country and require international cooperation for their conservation. Since many of the domesticated plants of Europe originated in countries other than those where they are cultivated today, the genetic material that would be most useful in improving their characteristics is also found in other countries or even in other continents. This indicates the critical importance of developing productive links between and among countries.
Contents:29.1 - Introduction
29.2 - Genetic diversity
29.3 - Trends
29.4 - Sustainable goals
29.5 - Strategies