PLATES
3. RESEARCH METHODOLOGY 1. Introduction
4.3. Valuing natural areas
4.3.1. Value of plants
Plants are important in controlling some catchment problems. In catchment areas that are not built on or developed, the ground is still covered with natural vegetation which plays the following roles: (Eco-facts 4 , 1999).
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Plants reduce the speed of runoff water over the ground which allows lots of rain water to sink into the ground and thus replenish the groundwater. The groundwater then slowly feeds the river to ensure that it flows all the year round.;
Plants prevent soil erosion since their roots stabilize the ground and stop it from washing away. Also the plants break the impact of the rain drops before they hit the ground, minimizing the erosion potential; and
Plants in wetland systems and on riverbanks are of special importance since their roots bind the ground, stop erosion, regulate the flow of water and at the same time, purify the water.
When plant cover in catchment areas is stripped from the ground through agricultural or industrial practice, there is an increase in runoff water and erosion. At the same time there is less water sinking in the ground and
less to replenish the aquifiers, with the result that the rivers only run in the rainy season. Much of the siltation in estuaries is due to the washing away of riverbanks that have destabilized due to the removal of plant cover.
The natural vegetation of the environment is usually totally destroyed by urban development. Vegetation in urban environments fulfils the following functions: (Hugo, Viljoen and Meeuwis, 1997).
• Micro-climate modification - shadow effects, windbreaks and lowering air temperatures by evapotranspiration ;
• Control of air pollution - gases like carbon and sulphur dioxide are absorbed by the leaves;
• Noise reduction - plants (including grass) absorb sound;
• Historic value - given to certain trees or tree-lined avenues;
• Social value - plants used as emblems or sought after for social status;
• Ecological value - resettlement and the establishment of animals (especially birds) will take place automatically if a suitable habitat is created. The cost of maintaining an ecologically viable natural park is much lower than the cost of maintaining a traditional urban park; and
• Ornamental/aesthetic value - apparently the most important reason why plants are kept in urban areas.
Direct, consumptive use values apply to natural products that may be harvested and used by the household or traded in the market place. People use woodlands for household needs as well as for raw materials for goods sold in the formal economy.
Forests and woodlands comprise a diverse range of environments which have a significant, but often poorly recognized economic, environmental and social value. The resource is declining, but at an unknown rate and as a result of pressures and changes which are not widely understood. Achieving sustainable management will require a marked improvement in our understanding of the value and status of the resource and the pressures that influence its management (DWAF, 1997).
About 12 000 plant species have been used for food, but only 150 species have been cultivated (Hugo, Viljoen& Meeuws, 1997).
Natural areas also provide a genetic pool for cross-fertilisation of wild plants with modem hybrid varieties.
This is done in order to strengthen the resistance of hybrid varieties to pests. Genetically modified organisms which are becoming more and more important also lean heavily on wild plants and animals for genetic material
Fuel wood, wood for carving, billlding materials and ingredients for traditional ceremonies and medicines are all obtainable from indigenous forests. Bark, roots and bulbs are removed from forests by traditional muti dealers.
Use may be perennial, as a more or less permanent element of the local economy (as in fuel wood), or intermittent, when people fall back on the fruits and other products of the woodlands during times of shortage, or for quality timber (Geldenhuys, 1997). Resource management is poor to non-existent, and prices paid for the raw product are much below their true value.
There are approximately 30 000 isangoma (diviners) and izinyanga (herbalists) that operate in KZN. This large number of herbalists place a great strain on the indigenous plant population, leading to a vast amount of threatened species (Club Card, May / June, 2003).
Each year approximately R26 million rand changes hands in medicinal plant trade in the Bushbuck Ridge area of Limpopo and some drug companies have estimated the national informal medicinal plant trade at between R500 million and RI billion. In 1990 exports of S.A. plants to Europe were estimated at around R52 million (Club card, May / June, 2003).
Anestimated 6 to 10 million tonnes of fuel wood is consumed per annum in SA (van Rensburg et. aI., 1997).
The bulk of this material is collected from natural woodlands, leaving only isolated patches of indigenous bush.
The extent to which the goods and services provided by the indigenous forest of KNR are used by the community is unknown, but indigenous trees and plants are used extensively for medicinal purposes and for fire wood. Commuters between place of residence and work have access to KNR at the Upper and Lower Molweni areas resulting in the potential for abuse of the indigenous vegetation. Efforts to fence off these areas have failed due to the cutting and theft of the fence wire (KNR NCO, pers. comm., 1999).
Although indigenous plants are being removed Idamaged, a total monetary value on these losses cannot be determined. Trees of which bark has been removed for medicinal purposes have been identified, but the removal of other plants e.g. bulbs cannot readily be quantified (KNR NCO, pers. comm., 1999).
Wetlands protect water. They purify it, store and regulate storm flow, ensure water in drought periods, recharge groundwater, control soil erosion and reduce flood destruction (Gowans, 1997). Wetlands influence the quantity and quality of run-off water and, if lost, have an estimated replacement value of R185 000 per hectare per annum (Botanical Society of SA, the Durban Unicity Environmental Management Branch, the Durban Parks Department and WESSA, 2000).
Consumption of water from the Emolweni River occurs outside KNR, but the quality (and quantity) of the water depends on its purification and release by wetlands within KNR. Thus KNR has an indirect ecological function that provides value for water consumption, the purity of which may be indirectly affected by pollution and erosion stemming from KNR. The wetlands in KNR effectively purifies the water that feeds the Emolweni river from which the Molweni community abstract their drinking water. Although consumption does not take place directly in KNR, the integrity of the reserve has an indirect effect on the value of the commodity.
Wetlands, apart from protecting wildlife, maintaining bio-diversity, having a high domestic stock grazing potential, are also valuable producers of fibre for handicraft and construction, and are of value for education and recreation. An estimated 50 percent of South Africa's wetlands have already disappeared (Gowans,
1997).