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by the protection of the vegetation and the combating of weeds and invader plants (Section 3). Accordingly, CARA considers as important resources of land, water and related aspects of the veld and the vegetation.
CARA also regulates rehabilitation of wetlands insofar as that activity falls under the definition of “conservation,” which, in relation to the natural agricultural resources, includes protection, recovery and reclamation of those resources (Section1). The Minister of Agriculture prescribes control measures with which all land users must comply (Section 6) (Winstanley, 2001).
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Changane catchment in Mozambique. Riverine swamps are confined to the main stem of the Limpopo and Changane tributary and the lower reaches of the Limpopo River in Mozambique (IWMI, 2003).
Several studies in southern and eastern Africa (Turpie, 2000; McCartney and van Koppen, 2004; Masiyandima, McCarteney and Kopper 2004) have shown that wetlands and their surrounding catchments support rural livelihoods through provision of a large range of natural resources. These include soils, water, plants and animals that are used by rural households in a wide range of activities such as the making of salt and pottery, plants harvested for use in food, medicines, crafts and for the provision of fuel wood and materials for furniture and house building, hunting and fishing.
Apart from harvesting and processing of natural resources, wetlands are also used for the cultivation of crops and for the grazing and watering of livestock. Some of the activities, such as cultivation, fishing and the harvesting of wild foods are clearly economical and are a means of earning income for the household.
Other uses of wetland resources, such as its water for domestic purposes, the soils for decorating houses and its array of wild foods contribute directly to household needs. The contribution of wetlands to the livelihoods of rural households living around them is important: in Zambia and Tanzania, annual incomes from wetlands can be as high as US $1000 per household (90% of the total household income), with high variation across sites and households.
Wetlands also take an essential part in food security, especially during the dry seasons or in drought years, when dry land farming, which is limited to the rainfall season, cannot adequately cater for the needs of these households.
For example, in Kilombero wetlands in south Tanzania, the wetlands contribute to the food intake of 98% of all the households in the villages
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nearby and more than 40% of the households acknowledge using the resources offered by the wetlands as a coping strategy during periods of food shortages (McCartney and van Koppen, 2004). Another interesting feature of wetlands is that they enable a wider range of crops than dry lands, and therefore provide dietary variety and nutrients that are otherwise unavailable among the traditional crops grown in the upland (Masiyandima et al., 2004).
The types of uses and the role that the wetlands play in rural people‟s welfare vary extensively according to natural settings of wetlands sites, the socio- economic characteristics of the communities and households (especially according to their access to various assets enabling them to harness the wetlands resources) and national historical and political context. This research was expected to show the role that wetlands at Mandlanzini play in the lives of the rural people of this area.
McCartney and van Koppen (2004) identify eight major functions of wetlands. These are for storage of precipitation and runoff, groundwater discharge, groundwater recharge, sediment retention, nutrient transformation, biomass production, maintenance of biodiversity, and chemical cycling.
Woodward and Wui (2001) add two other functions: it serves as a habitat for aquatic species and as a habitat for terrestrial and avian species. These functions benefit not only people living on or nearby wetlands but also hold beneficial effects on users downstream. The type and intensity of wetlands uses have potential impacts on these functions. Increasing population is partly due to the resettlement imposed by political regulation (the
“villagisation” process in Tanzania) or by the spontaneous immigration of populations attracted by better natural resources. All of these factors have put a high pressure on wetland ecological processes. In some cases, the phenomenon is even worsened by the fact that access to other surrounding
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natural areas is now denied to local communities due to their incorporation into conservancies.
The increasing frequency of drought has also driven farmers to extend wetlands areas under cultivation. Several negative environmental impacts of human use of wetlands are reported. These include a decline in soil fertility, reduction of biodiversity, a decline in wildlife population, soil erosion leading to increased sediment load downstream, water pollution due to use of agro-chemicals or due to human and livestock waste, and reduced water quantity on-site (productivity of wells) and downstream (reduced flows and rapidly receding water levels during the dry season). If local populations recognize the effects that directly threaten their livelihoods (reduction of water availability, diminution of water quality, reduction of soil fertility), they generally do not acknowledge the impacts on downstream users (McCartney and van Koppen, 2004; Masiyandima et al., 2004).
A major cause of wetland degradation all over the world, and more specifically in developing countries, is precisely the lack of knowledge by government planners, natural resource managers and wetland users of the ecological processes by which wetlands provide their diverse benefits and the ignorance of these benefits themselves. Even in the scientific community, there is a large gap in the understanding of the effects of land and water uses in the wetlands on hydrological processes in the catchments. Previous wetland conservation policies that relied only on protection have shown their limits. Solutions to ensure protection of these fragile environments while maintaining the livelihood benefits to local people need a multi-pronged approach associating all stakeholders, especially local communities, in the decision-making process (Masiyandima et al., 2004).
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In particular, there is a need for more information on: (a) the monetary and non-monetary value of goods and services provided by wetlands systems; (b) the factors that influence peoples‟ access to and control over wetlands resources; (c) the social and economic costs of degradation of wetlands, and (d) the quantitative relationships between different agricultural practices within wetlands and the consequent environmental, social and economic implications. The next section of this study examines the characteristics of wetlands goods and services from an economic point of view and reviews the approaches proposed by economic science to address the issues related to these characteristics.