Encyclopedia > Biodiversity

  Article Content

Biodiversity

Biodiversity or biological diversity is a neologism from biology and diversity. It is the diversity of and in living nature.

Table of contents

Biodiversity definitions

Origin of the term biodiversity

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. 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.

Since 1986 the term and the concept have achieved widespread use among biologists, environmentalists, political leaders, and concerned citizens world-wide. It coincided well with the expansion of concern over extinction observed in the last decades of the 20th century.

The three levels of biodiversity

Biological diversity (in short, biodiversity) has no single standard definition; some are:
Biological diversity is a measure of the relative diversity between organisms present in different ecosystems. This definition includes diversity within species, between species, and between 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 described:

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

The gene is the fundamental unit of natural selection, thus of the evolution, and 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

  • for geneticists[?], biodiversity is the diversity of genes and organisms. They study processes such as mutations, gene exchanges, and genome dynamics that occur at the DNA level and authorize evolution.

  • for biologists, biodiversity is the diversity of organisms and species, but also the way these organisms function. Organisms appear and disappear; sites are colonized by organisms of the same species or by another. Organisms and species do not use the same strategies of reproduction, depending on their environment. Some species develop social organisations[?] to improve their reproduction goals or use neighbor species that live in communities.

  • for ecologists, biodiversity is also the diversity of durable interactions between species. It not only applies to species, but also to their environment and the ecoregions the organisms live in. In each ecosystem, living organisms are part of a whole, they interact with one another, but also with the air, water, and soil that surrounder them.

What are biodiversity 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, ecosystem, and landscape 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. The biodiversity related to food and agriculture uses 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 economical 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 Evaluation of biodiversity

How to measure biodiversity ?

From the view point previously defined, no single objective measure of biodiversity is possible, only measures relating to particular purposes or applications.
For conservationists, this measure should quantify a value that is at the same time broadly shared among people for whom they are acting and considered as being in need of protection.
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 production and environmental sustainability in a changing and ever adapting world. 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 of years and 99% of the species that have ever lived on earth are today extinct.

Biodiversity is not distributed evenly on earth. Flora and fauna are different depending on climate, altitude, soils and other species. For a listing of distinct ecoregions based on these distributions, see the WikiProject Ecoregions.

Species inventory

Systematic[?] is a way of analyzing the biodiversity in its capacity to distinguish an species from another. 1,75 million species were described; however, the estimates of the true number of alive species go 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 occuring between the species tend to complexify the inventory.

Biodiversity-rich countries

  • Brasil is said to represent 1/5 of the world biodiversity, with 50.000 plant species, 5.000 vertebrae, 10-15 millions of insects, millions of microorganisms
  • India is said to represent 8 % of the recorded species, with 47.000 plants species and 81.000 animals.

See also : biogeography -- Amazonian forest -- species inventory[?]

Economical value of biodiversity

Ecologists and environmentalists were the first to insist on the economical aspect of biological diversity protection. Thus, Edward O. Wilson wrote in 1992, that la biodiversité est l'une des plus grandes richesses de la plančte, et pourtant la moins reconnue comme telle.
Most people are seeing in biodiversity a reservoir of resources, usable to manufacture food, pharmaceutical, 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 ressources.

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 ways. 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 1 over 8 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, other pointed out that no properties rights or no access regulation to 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. Though not everybody agree on today extinction event extent, most consider essential that this diversity be preserved, as a precaution. There are basically two main types of conservation options, in-situ and ex-situ conservation. In-situ conservation is usually seen as the ultimate conservation strategy. However its implementation is not always feasible. For example, habitats destruction of rare or endangered species requires ex-situ conservation efforts. Besides, ex-situ conservation can provide a back-up solution to in-situ conservation projects. Some believe both types of conservation are required to ensure proper preservation. An example of in-situ conservation effort is the setting-up of protection areas. Storing germplasts in seedbanks is an example of an ex-situ conservation effort, which allow the preservation of large populations of plants with minimal genetic erosion.

The threat to biological diversity was one of 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.

  • "Law and ecosystems" relationship is very ancient and has consequences on biodiversity. It is related to properties rights, private and public. It can define protection for threatened ecosystems, but also some rights and duties (for example, fishing rights, hunting rights).
  • "Laws and species" is a more recent issue. It defines species that must be protected because threatened by extinction. Some people question application of these laws.
  • "Laws and genes" is only about a century old. While the genetic approach is not new (domestication, plant traditionnal selection methods), progress made in the genetic field in the past 20 years lead to the obligation to tighten laws. With the new technologies of genetic and genetic engineering, people are going through gene patenting, processus patenting, and a totally new concept of genetic resource. A very hot debate today seeks to define whether the resource is the gene, the organism, the DNA or the processus.

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 of 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 diseappearing and being replaced by the idea of a dynamic conservation, through the notion of resource and innovation.<br> The new agreements commit countries to conserve the biodiversity, develop ressources 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.

See also :

External link : Text on the Convention on biodiversity : http://www.biodiv.org/convention (http://www.biodiv.org/convention/articles.asp)



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Rubiaceae

... ...