US undertakes African ecosystem survey

A group of scientists and students has begun a 600 mile journey across southern Africa to explore the links between soil, vegetation and atmospheric emissions and how these affect the functioning of the ecosystems of southern Africa.

The research caravan is part of the Southern African Regional Science Initiative 2000 (SAFARI 2000), a three-year study of southern Africa’s ecology, air quality and land use.

In addition to the field study, the US space agency, NASA, will provide images from its Terra, Landsat 7 and SeaWiFS satellites plus aircraft measurements, measurements from observation towers, ozone-measuring balloons and collaborative research with African scientists.

Researchers will travel to five different ecosystems along a north-south route from Mongu in Zambia to Tshane, Botswana. This area, dubbed the ‘Kalahari Transect’ for its underlying sandy soil, has been identified as a key global change study area by the International Geosphere-Biosphere Program. A final caravan sets off from Mongu early next year heading east to survey the Miombo Forest region.

At each survey site, participants will stake out a 1km2 plot and measure the type, density and height of all the vegetation. They will also record the way sunlight is absorbed and reflected by the plants and soil in order to corroborate NASA’s satellite imagery. This is intended to improve NASA’s ability to monitor global climate change.

The caravan survey will produce the first co-ordinated measurements of several different ecosystems, from woodlands in the north to shrubland in the south. This data combined with chemical analysis of rainfall and atmospheric particles will help to explain how the nutrient-poor soil in this region can support vegetation. One current hypothesis is that nutrients sent into the atmosphere by extensive fires are blown here by winds and deposited in the soil.

Ozone in the lower atmosphere will also be monitored using balloon-borne instruments.

A six-week airborne campaign will begin in August at the height of the dry season. Aircraft will conduct flights over nine southern African countries to study the circulation and composition of the atmosphere and pollution from biomass burning and industrial emissions. Southern Africa is subject to some of the highest levels of biomass burning in the world.

The first SAFARI field campaign in 1992 produced information on biomass burning and the long-range movement of air pollution.

In 1998 President Clinton announced the ‘Southern Africa Environmental Review’ during his trip to Africa in response to the increasing pressures on the environment caused by the rapid growth in population and economic activity in the region.

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