Biodiversity

From Wikipedia, the free encyclopedia.

Biodiversity or biological diversity is a neologism from bio and diversity. It is the diversity of and in living nature. Diversity, at its heart, implies the number of different kinds of objects, such as species. However, defining biodiversity or measures of biodiversity, is not so simple.
The word biodiversity was first coined by the entomologist E.O. Wilson in 1986, in a report for the first American Forum on biological diversity organized by the National Research Council (NRC). The word biodiversity was suggested to him by the staff of NRC, to replace biological diversity, considered to be less effective in terms of communication.
The term biological diversity itself, was coined by Thomas Lovejoy in 1980. Since 1986 the term and the concept have achieved widespread use among biologists, environmentalists, political leaders, and concerned citizens world-wide. This use has coincided with the expansion of concern over extinction observed in the last decades of the 20th century.

Biodiversity definitions

The three levels of biodiversity

Biological diversity (in short, biodiversity) has no single standard definition. One definition holds that biological diversity is a measure of the relative diversity among organisms present in different ecosystems. 'Diversity' in this definition includes diversity within species, among species, and comparative diversity among ecosystems. Another definition, simpler and clearer, but more challenging, is the totality of genes, species, and ecosystems of a region. An advantage of this definition is that it seems to describe most instances of its use, and one possibly unified view of the traditional three levels at which biodiversity has been identified:

The lattermost definition, which conforms to the traditional five organisation layers in biology, provides additional justification for multilevel approaches.

If the gene is the fundamental unit of natural selection, thus of evolution, some, like E.O. Wilson, say that the real biodiversity is the genetic diversity. However, the species diversity is the easiest one to study.

Biodiversity and approaches

What are biodiversity's roles?

Biodiversity has contributed in many ways to the development of human culture, and, in turn, human communities have played a major role in shaping the diversity of nature at the genetic, species, and ecological levels.

For all humans, it is first a resource for daily life, providing food (crops, livestock, forestry, and fish), fibers for clothing, wood for shelter and warmth, medication, and energy. Such 'crop diversity' is also called agrobiodiversity.

Ecosystems also provide us various supports of production (soil fertility, pollinators, predators, decomposition of wastes...) and services such as purification of the air and water, stabilisation and moderation of the climate, decrease of flooding, drought and other environmental disasters.

If biological resources represent an ecological interest for the community, their economic value is also increasing. New products are developed thanks to biotechnologies, and new markets created. For society, biodiversity also is a field of activity and profit. It requires a proper management setup to determine how these resources are to be used.

Finally, the role of biodiversity is to be a mirror of our relationships with the other living species, an ethical view with rights, duties, and education.

See also: ecotourism, cultural diversity, local food.

Evaluation of biodiversity

How to measure biodiversity?

From the viewpoint previously defined, no single objective measure of biodiversity is possible, only measures relating to particular purposes or applications.

For practical conservationists, this measure should quantify a value that is at the same time broadly shared among locally-affected people.

For others, a broader and more economically defensible definition is that measures should allow to ensure continued possibilities both for adaptation and future use by people, assuring environmental sustainability. As a consequence, biologists argued that this measure is likely to be associated with the variety of genes. Since it cannot always be said which genes are more likely to prove beneficial, the best choice for conservation is to assure the persistence of as many genes as possible.

For ecologists, this approach is sometimes considered inadequate and too restricted.

Biodiversity: time and space

Biodiversity is not static: it is a system in constant evolution, from a species, as well as from an individual organism point of view. The average half-life of a species is around one million years and 99% of the species that have ever lived on earth are today extinct.

Biodiversity is not distributed evenly on earth. It is consistently richer in the tropics. As one approaches polar regions one finds larger and larger populations of fewer and fewer species. Flora and fauna vary depending on climate, altitude, soils and the presence of other species. For a listing of distinct ecoregions based on these distributions, see the WikiProject Ecoregions.

Species inventory

Systematics assesses biodiversity simply by distinguishing among species. At least 1.75 million species have been described; however, the estimates of the true number of current species range from 3.6 to more than 100 million. Some also say that the knowledge of the species and the families became insufficient and must be supplemented by a greater comprehension of the functions, interactions and communities. Moreover, exchanges of genes occurring between the species tend to add complexity to the inventory.

'Hotspots' of biodiversity

See also: biogeography, Amazonian forest, species inventory, extinction.

Economic value of biodiversity

Ecologists and environmentalists were the first to insist on the economic aspect of biological diversity protection. Thus, Edward O. Wilson wrote in 1992, that la biodiversité est l'une des plus grandes richesses de la planète, et pourtant la moins reconnue comme telle.

Most people see biodiversity as a reservoir of resources to be drawn upon for the manufacture of food, pharmaceutical, and cosmetic products. This concept of biological resources management probably explains most fears of resources disappearance related to the erosion of the biodiversity. However, it is also is the origin of new conflicts dealing with rules of division and appropriation of natural resources.

Economic estimation of the value of biodiversity is a necessary precondition to any discussion on the distribution of biodiversity richnesses. This goal must also make it possible to determine financial means to devote to its protection. This new field of study is called: economic value of biodiversity.

Is biodiversity threatened?

During the last decades, an erosion of biodiversity was observed. A majority of biologists believe that a mass extinction is under way. Although divided over the numbers, many scientifics believe that the rate of loss is greater now than at any time in history.

Some studies show that about one of eight known plant species is threatened with extinction. Every year, between 17,000 and 100,000 species vanish from our planet. Some people say that up to 1/5 of all living species could disappear within 30 years. Nearly all say that the losses are due to human activities, in particular destruction of plant and animal habitats.

Some justify this situation not so much by a species overuse or ecosystem degradation than by their conversion in very standardized ecosystems (e.g., monoculture following deforestation). Before 1992, others pointed out that no property rights or no access regulation of resources necessarily lead to their decrease (degrading costs having to be supported by the community).

Among the dissenters, some argue that there are not enough data to support the view of mass extinction, and say abusive extrapolations are being made on the global destruction of rainforests, coral reefs, mangrove swamps, and other rich habitats.

Biodiversity management: conservation, preservation and protection

The conservation of biological diversity has become a global concern. Although not everybody agrees on extent and significance of current extinction, most consider biodiversity essential. There are basically two main types of conservation options, in-situ and ex-situ conservation. In-situ conservation. In-situ is usually seen as the ultimate conservation strategy. However, its implementation is sometimes unfeasible. For example, destruction of rare or endangered species' habitats sometimes requires ex-situ conservation efforts. Furthermore, ex-situ conservation can provide a backup solution to in-situ conservation projects. Some believe both types of conservation are required to ensure proper preservation. An example of an in-situ conservation effort is the setting-up of protection areas. An example of an ex-situ conservation effort, by contrast, would be planting germplasts in seedbanks. Such efforts allow the preservation of large populations of plants with minimal genetic erosion.

The threat to biological diversity was among the hot topics discussed at the UN World Summit for Sustainable Development, in hope of seeing the foundation of a Global Conservation Trust to help maintain plant collections.

See also: conservation, seedbank, IUCN, Global 200.

Juridical status of biological diversity

Biodiversity must be evaluated and its evolution analysed (through observations, inventories, conservation...) then it must be taken into account in political decisions. It is beginning to receive a juridical setting.

The 1972 UNESCO convention established that biological resources, such as plants, were common heritage of mankind. These rules probably inspired the creation of great public banks of genetic resources, located outside the source-countries.

New global agreements (Convention on Biological Diversity), now gives sovereign national rights over biological resources (not property). The idea of static conservation of biodiversity is disappearing and being replaced by the idea of a dynamic conservation, through the notion of resource and innovation.

The new agreements commit countries to conserve the biodiversity, develop resources for sustainability and share the benefits resulting from their use. Under these new rules, it is expected that bioprospecting or collection of natural products has to be allowed by the biodiversity-rich country, in exchange for a share of the benefits.

Sovereignety principles can rely upon what is better known as Access and Benefit Sharing Agreements (ABAs). The Convention on Biodiversity spirit implies a prior informed consent between the source country and the collector, to establish which resource will be used and for what, and to settle on a fair agreement on benefit sharing. Bioprospecting can become a type of biopiracy when those principles are not respected.

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