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| Titel |
Extent and drainage status of organic soils in the Lake Victoria catchment |
| VerfasserIn |
Reni Barthelmes, Alexandra Barthelmes, Hans Joosten |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250135856
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| Publikation (Nr.) |
 EGU/EGU2016-16772.pdf |
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| Zusammenfassung |
| When considering peatlands and organic soils in the tropics, the huge areas in SE Asia prevail
in public and scientific perception, whereas Africa has largely been out of focus. However,
East Africa contains large areas of organic soils as well. They basically occur in the high
altitudes of the uplifted flanks of the East African Rift System, isolated volcanoes and the
Ethiopian highlands, in the Zambezian floodplains (e.g. Zambia), and in coastal environments
(e.g. Mozambique and Madagascar).
We used a mapping approach that integrates old field data and maps, specialized landscape
and peatland-related knowledge, and modern RS and GIS techniques to elaborate a
comprehensive and rather reliable overview of organic soils (incl. peatlands) in the Lake
Victoria catchment. Maps at a scale of 1:25,000 have been prepared for Burundi, Kenya,
Rwanda, Tanzania and Uganda. The land use intensity has been estimated for all organic soil
areas based on satellite and aerial imagery.
Feeding the Nile River, sustaining a fast growing and widely poor population and already
facing climatic changes, organic soils of the Lake Victoria neighbouring countries are
partially under heavy threat. We mapped 10,645 km2 of organic soils for the entire area of
which 8,860 km2 (83.2%) seem to be in near natural condition. We assume slightly drainage
and low degradation for 564 km2 (5.3%) and intensive drainage and heavy degradation for
1,222 km2 (11.5%). Degradation hotspot is Burundi with 522 km2 (79.5%) of heavily drained
and degrading organic soils. This area assessment has been quite conservative to not
overestimate the extent of organic soils. A reserve of 5-7,000 km2 of wetlands in the Lake
Victoria catchment may include peatlands too, which needs to be confirmed in field
surveys.
Considering the key role of peatlands and organic soils for water provision and
regulation and their rapid degradation due to drainage and inappropriate use, this
inventory might be a step towards organic soil protection, and the development
(or rediscovery) of sustainable land use options for undrained or future rewetted
areas. |
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