What is biodiversity? Print

What is biodiversity?

Biodiversity has many definitions, but probably the simplest one is that biodiversity is "the variability among living organisms from all sources on earth". It comprises the different plants, animals and micro-organisms, the genetic information they contain and the ecosystems they form. Biodiversity includes diversity within species, between species, and among ecosystems. The concept of biodiversity also covers how this diversity changes from one location to another and over time.

Status of global biodiversity

Photo: © McPHOTO / Still Pictures

In recent years an above average loss in biodiversity has become certain. Worldwide, the loss of biodiversity has accelerated to an unprecedented level. It has been estimated that the current global extinction rate is already 1,000 to 10,000 times higher than the natural background extinction rate. Scientists expect that by the middle of this century we may be losing three species per hour - three unique species which have gradually evolved over hundreds of thousands of years. If humankind is not successful in halting the loss of biodiversity, our generation might become witness to the greatest catastrophe in the history of life since the disappearance of the dinosaurs 65 million years ago.

Why is biodiversity important?

Biodiversity plays an important role in the way ecosystems function and in the many services they provide. Services include nutrients and water cycling, soil formation and retention, resistance against invasive species, pollination of plants, regulation of climate, as well as pest and pollution control by ecosystems. For these ecosystem services high biodiversity levels are vital. For example, the disadvantages of low-levels of biodiversity have become evident in monocultural farming - where entire crops can fall victim to parasites due to lack of variability amongst the plants. Healthy ecosystems with high biodiversity levels have higher resistance and are less prone to fall victim to diseases.

Global threat – What factors lead to biodiversity loss?

There are both natural and human-induced factors which lead to biodiversity loss. However, the biodiversity of our planet is predominantly threatened by an explosion of humanity and its technology.

The overexploitation of our natural resources, land cover change, pollution, deforestation, overfishing, invasive alien species and many other factors have a direct or indirect impact on the loss of global biodiversity.

Photo: © E. Hummel / Still Pictures

A few examples:
  • The exploitation of the world's oceans through overfishing is causing the loss of marine biodiversity at alarming rates.
  • The loss of habitats, for example through the destruction of forests in central Africa, is leading to the extinction of a number of species, such as the Western Gorilla.
  • Invasive alien species, such as the example of rats brought to the Galapagos Islands are threatening a number of endemic bird species.

Migratory birds as indicators for the status of biodiversity

Migratory birds are of great ecological and economic value as they are an integral part of the global biological diversity. Nearly half the world’s 10,000 bird species depend on the forests, wetlands and grasslands  - they are inhabitants of virtually all ecosystems of the world, so that they can be labeled some of the best indicators for the status and trends of wider biodiversity.