USING SATELLITES TO MONITOR WORLD HERITAGE SITES

The forest habitat of Africa's great apes dwindles each day under the assault of logging and mining companies, poachers and human settlement. Such activities, which could lead to the extinction of such endangered species, is hard to monitor in mountainous and other inaccessible regions. To fill the gap, UNESCO has just completed - using satellite images - the first 1:200,000 scale map of the Virunga National Park, an officially-endangered World Heritage site in the Democratic Republic of Congo that is home to a colony of 350 mountain gorillas.

A recent UN Environment Programme (UNEP) report said 90 per cent of great ape habitats will have disappeared by 2030 if nothing is done to preserve them. The UNESCO map, produced with the help of the European Space Agency (ESA) and the University of Gent (Belgium), means forest rangers can see exactly where they need to increase their activities and try to stop human incursions.

The map, part of a pilot project begun in October 2001 by UNESCO and the ESA, was made from pictures taken from 800 km above the Earth and from data gathered on the ground by environmental activists. The two kinds of data were combined using computer tools such as Geographical Information Systems (GIS).

The Virunga National Park and its mountain gorillas - half of the 600 or so remaining in the world - are now covered. The mapping has now been extended to neighbouring forest reserves where the other mountain gorilla colonies live - the Bwindi Impenetrable and Mgahinga Gorilla national parks in Uganda, and the Volcanoes National Park in Rwanda.

In recent years, remote sensing, combined with new technology to interpret data has been much used in environmental monitoring. But it has only been useful for monitoring large areas because satellite picture resolution is limited.

A new generation of civilian satellites has changed this. The IKONOS satellite, for example, can give much better resolution while ERS or Radarsat radar satellites can take pictures that are not affected by cloud cover or poor light. In addition, pictures from once ultra-secret spy satellites such as CORONA are now available for scientific use.

This means remote sensing can be used in future to monitor cultural World Heritage sites, especially to check on looting or other damage to sites. Some 200 space technology and world heritage protection experts from all over the world will meet at a conference in Strasbourg (France) from November 5 to 8 to discuss how this technology can best be used and how much it will cost.