N. N Gichuki

Socio-economic values and traditional strategies of managing wetland resources in Lower Tana River, Kenya

Understanding local peoples socio-economic values of wetlands and traditional mechanisms of managing natural resources forms the basis of conserving them. In order to sustainably manage wetland resources in Tana River National Primate Reserve (TRNPR) and its environs, a study was carried out to document values, threats and traditional strategies of managing natural resources. The target communities were the Pokomo and Wardei who inhabit the TRNPR. The study was carried out in different periods in the year 2000 and 2001 and entailed administration of questionnaires, interviews and focused group discussions. Thirty residents were interviewed from six villages in the west bank of Tana River. The study found that oxbow lakes and Tana River formed the main types of wetlands and provided multiple values such as farming, transportation, security and social-cultural values to the local people. These values formed an important premise for conservation. Farming and fishing were the main economic activities of the Pokomo people while Wardei combined livestock rearing with occasional shifting cultivation. The two communities used different traditional systems in managing resources that they needed for their livelihood. The study concludes that the local people can and indeed must play a central role in the conservation of threatened wildlife and habitats in the Lower Tana River.

Characterization of Environmental Gradients Using Physico-Chemical Measurements and Diatom Densities in Nairobi River, Kenya

Degradation of water resources due to anthropogenic activities is a major problem all over the world. Monitoring changes in water quality is expensive but essential for management of water resources. Diatom assemblages can serve as useful indicators of changes in water quality. In order to determine changes in stream water quality in an urban environment, densities of epilithic diatom communities on both natural and artificial substrates were sampled in Nairobi River, Kenya in September 2000. Sampling of water and diatoms was carried out in almost equidistant sites along a 60 km stretch of the Nairobi River. Environmental (water physico-chemical and nutrients) data was explored by Principal Correspondence Analysis (PCA) and sites split into three groups of upper-, mid- and lower stream. Most abundant diatom taxa on both substrates were selected and their relationship with environmental variables determined. On artificial substrates, Gomphonema parvulum , Nitzschia palea and Nitzschia umbonata were the most abundant and were significantly related with total dissolved solids, nitrate, conductivity and turbidity. Temperature, altitude and pH interacted significantly with dominant diatom species on natural substrates, which included Gomphonema parvulum , Nitzschia palea and Navicula subminuscula . Non-parametric analyses showed that diatom densities in natural and artificial substrates were significantly different and were affected by different environmental variables. Our results indicate that abundant diatom species can be used to describe major types of aquatic environmental gradients and can serve as good indicators of ecological conditions in tropical streams and rivers. This study also showed that diatoms from artificial and natural substrates can be used to provide complementary information.

Participation of Local Communities in the Management of Wetlands in Magadi Area, Kenya

Wetlands are lands that are transitional between terrestrial and aquatic systems where the water is usually at or near the surface of the land or land that is covered with shallow water (Cowardin et al. 1979, Roggeri 1995). In the context of dry lands, wetlands are areas that are permanently, seasonally or occasionally water logged with fresh or saline water that supports characteristic animals and plants. In the dry lands of eastern Africa, wetlands cover about 3 percent of the total land area and include shallow lakes and margin s of deep lakes, swamps and marshes found on upper flood plains of major rivers, coastal river flood plains and high mountain peat bogs and tarns (Omoding 1995). These ecosystems support valuable biodiversity, including large numbers of mammals, reptiles, fishes and birds as well as diverse plant communities (Denny 1993). They also provide valuable resources and environmental benefits, such as biomass cropping for livestock pasture, water supply, agriculture, fisheries and subsistence hunting of wildlife that sustain local economies and communities (Shumway 1999).