We analysed the extent of ecological damage of gully and inter-gully erosion in a sub-catchment situated in the drylands (300mmyr(-1)) of the winter rainfall area of South Africa where small-stock farming on rangeland is the main source of income. We applied low-cost measures to revegetate the bare sites of the inter-gully erosion and stabilised gully erosion by loosening soil surfaces and applying geotextile and constructing check dams to reverse gully erosion. We compared vegetation cover, silt accumulation and penetration resistance of the soil upslope of the check dams with the situation downslope of the check dams and untreated gullies as controls. For the treated bare patches, we compared penetration resistance and vegetation cover with untreated controls. Two years after implementation, the restoration measures resulted in increased soil depth and vegetation cover upslope of the check dams and increased vegetation cover on the treated bare patches. We calculated the net present value of the restoration measures based on the financial benefit that a landowner can realistically expect under current economic and governance conditions (i.e. payment for additional livestock and for C sequestration). At the current rates of return for livestock production or carbon sequestration over a 20-year period, rehabilitation of this sort is not financially feasible for private landowners. Either the current payment for carbon sequestration would have to be increased by a magnitude of 40-80, or restoration measures would have to be funded by the public or private sector to make them financially viable for landowners.
In 2008, the farmland was purchased by the World Wide Fund for Nature South Africa to conserve its unique biodiver- sity and to restore erosion damage...soil and water conservation measures (i.e. gul- ley check-dams and bare-patch treatments, see succeeding text for details) were implemented on a section of the property with badly eroded soils... bare patch treatment: The bare patches were restored by loosening the exposed subsoil with a pickaxe to a depth of approximately 15 cm. Organic material (sawdust of Pinus spp.) and seed-rich top- soil taken from the site was introduced and the surface sub- sequently covered by the same geotextile as used for the check dams. The geotextile was secured by weighing the edges down with rocks from the surrounding farmland.... check dams treatment: constructed in the winter months (April–August) of the year 2011 from rocks, wooden poles, geotextile and brush. The wooden poles were largely pro- duced by clearing alien tree stands (pine and poplar species) elsewhere on the property and were placed horizontally across the gullies at intervals of between 10 to 20m. Pieces of geotextile (Soil Saver 292 ®, 100% natural jute fibres from Kaytech, South Africa) of about 1·20 m × 2 m in size were folded over the poles and secured on the upstream side by weighing them down with stones and soil to prevent them from being washed out by run-off water. These structures were then bolstered by packing rocks below the check dams. To further calm the flow of the run-off water and promote in- filtration, brush packs using the branches of shrubs from the farm secured by rocks were placed on the upstream side of the check dams. An intended effect of these check dams was to filter the run-off water, retaining most silt, seed and organic material behind the geotextile and within the brush packs.
|Climate change impacts||Effect of Nbs on CCI||Effect measures|
|Biomass cover loss||Positive||Vegetation total (live and dead) Live plants Grass (live) Annual dicots (live) Perennial herbaceous dicots (live) Dead plants Total cover (dead) Grass (dead) Perennial herbaceous dicots (dead) Woody litter|
sub-catchment on the farm Avontuur (31°15′37′′S, 19°04′04′′E) on the Bokkeveld Plateau of South Africa. The 1300-ha farm is located in the Namakwa District of the Northern Cape Province, 15 km north of the town Nieuwoudtville.