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Observing Terrestrial Biodiversity, Robert Scholes

Currently there is no reliable baseline,
at a global scale, for the rate
of biodiversity loss


Biological diversity - the variety of life on Earth - is one of the five focal areas of the GTOS mandate. As GTOS moves from concept to operation, the focal areas are one by one being elaborated into comprehensive programmes. Now that the climate-related observation system has gained momentum, it is time to concentrate on biodiversity.


At a global scale, the principal potential beneficiaries of such observations are the international treaties that deal with aspects of biodiversity. These include the UN Convention on Biological Diversity (CBD), the Ramsar Convention on Wetlands, and the recently-signed Convention on Migratory Species. Many other treaties have an indirect interest in biodiversity, including the UN Framework Convention on Climate Change, and the Convention to Combat Desertification. The concept of biodiversity extends beyond "wild" species in natural and semi-natural ecosystems. It also addresses the diversity of domesticated species that are the source of most food and fibre production.

The vast bulk of the diversity in the modern world exists outside of formal protected areas, in the same environments that humans use for agriculture, forestry and settlement. Loss of habitat is one of primary reasons for biodiversity erosion, at rates estimated to be ten times or more faster than the background rate of species turnover. Other contributing factors are overharvesting, persecution, deliberate or accidental poisoning, and - increasingly - climate change.

Recognizing the widespread threats to biological diversity, and its links to human well-being, the UN Millennium Development Goals have a target to reduce the rate of biodiversity loss, by the year 2010. An impediment in reaching this goal is knowing the degree to which it has been achieved. Currently there is no reliable baseline, at a global scale, for rate of biodiversity loss. This is clearly an area where a harmonized, reliable observation system is called for.


One of the main problems in tackling the issue of biodiversity observations is that "biodiversity" is not a single, easily measured thing. First, by definition, it is about many things, and their awesome range of differences. Second, diversity occurs at a range of levels of organization. Obviously one hears about the diversity of species (some 14 million, of which the majority are scientifically undescribed), but equally important are the diversity of ecosystems (assemblages of species, in interaction with their environment), and the genetic diversity that occurs within species. Finally, the diversity at each of these levels can be expressed in terms of composition (what types of things are there), structure (what is their spatial pattern) and function (how do they work) (See Figure 1). Simple measures, such as the rate of species extinction, are easily grasped but hard to prove, and tend to provide information when it is too late to intervene.


As in other GTOS focus areas, elements of an observing system exist already at local, national and international scales. Thus most countries have records of biological diversity in herbaria, museums, libraries and various databases, frequently associated with protected areas. At a local scale, worldwide, thousands of voluntary citizen-based organizations make observations of birds, mammals, frogs, insects, fish, reptiles and plants. Many of the observation sites in the TEMS database routinely include biodiversity observations. GOFC-GOLD activities in mapping land cover is an example of a relevant global activity, along with international databases maintained by the International Union for the Conservation of Nature and other organizations.

The role of GTOS, in collaboration with many partners, is to help organize these fragments into an efficient and effective integrated system. This will involve promoting harmonization of observations, encouraging the sharing of data, identifying critical gaps, and helping to fill gaps where possible. The key partners in this endeavour are national governments; international research initiatives, such as Diversitas; international biodiversity-related NGOs, such as IUCN and WWF; international treaty organizations; and UN bodies such as FAO and UNEP.


GTOS has been involved in helping to bridge the gap between emerging research and policy needs. On the one hand, GTOS has participated in the redesign of the Diversitas research programme, and, on the other, discussed with treaty bodies and national experts ways to quantify biodiversity and its loss.

The next steps are to establish a GTOS working group to help expand the TEMS biodiversity module into a fully-fledged package of well-considered variables, and then to document and develop, where necessary, agreed protocols for making the observations and sharing the data. A start was made on these activities at the International Symposium on Global Biological Diversity, in Berlin, 1 - 4 December 2003, where a workshop co-hosted by GTOS and DIVERSITAS was planned to map out the key issues and initiate a process to address them.

Figure 1. The components of biodiversity, at various levels of organization, and in relation to composition, function and structure.

Source: Adapted from Noss. 1990.
Indicators for monitoring biodiversity:
A hierarchical approach.
Conservation Biology, 4: 355 - 364.

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