Environmental degradation is a serious problem in Lesotho, Africa. The majority of
studies dealing with soil loss and gully erosion have mainly focused on the mechanics of
the erosion. However, mountain watersheds are sensitive and vulnerable to degradation
and in so being, have large inherent environmental implications. Gully erosion diversifies
the micro-topographical and hydrological environment. The severe changes and eventual
system degradation incurred as a result of gullying has rarely been quantified. This paper
specifically highlights mire phytogeographic responses to valley head degradation at
selected sites in eastern Lesotho by comparing patterns observed in gullied mires to those
seen in other non-gullied mires. Soil and vegetation belt transects are set up across five
mires (2 gullied) in the highlands of eastern Lesotho. The response of many of the plant
species to the overall environmental gradient was asymmetrical and unimodal in pattern.
The spatial distribution of the soil’s physical properties, topography and vegetation
community patterns were found to reflect the spatial mosaic of the soil moisture gradient.
The negative impact that gullying has on the ecohydrological regime of the valley heads
is evident and is allowing for shrub encroachment. Both the wetland and dryland
vegetation communities correlate strongly with the changes in the surface soil moisture
gradient. Gully erosion is clearly a threshold phenomenon. Continued grassland
degradation, accelerated soil erosion and subsequent gullying of the wetlands will lead to
plant and animal diversity loss, decreased livestock productivity, sediment-laden water
and shortened dam life-span.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/5836 |
| Date | 11 November 2008 |
| Creators | Deschamps, Christine L. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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