The aim of this study was to assess the influence of urban waste, sewage and other human centred activities on the microbiological quality of the river Subin, which flows through the metropolis of Kumasi, Ghana, and serves as drinking water for communities downstream. Three sites, Racecourse, Asafo and Asago, on the Subin were monitored over a year for total coliforms, faecal coliforms, enterococci and biochemical oxygen demand. Bacterial indicator numbers (geometric mean 100 ml(-1)) varied from 1.61 x 10(9) to 4.06 x 10(13) for total coliforms, 9.75 x 10(8) to 8.98 x 10(12) for faecal coliforms and 1.01 x 10(2) to 6.57 x 10(6) for enterococci. There was a consistent increase in bacterial loading as the river flows from the source (Racecourse) through Kumasi. Bacterial numbers were significantly (p < or = 0.05) higher during the rainy season compared with the dry (harmattan) season. The biochemical oxygen demand ranged from 8 mg l(-1) at the source of the river to 419 mg l(-1) at Asago; none of the sites achieved internationally accepted standards for water quality. The River Subin becomes grossly polluted as it flows through Kumasi and at Asago, a rural community downstream of Kumasi that abstracts water from the river for drinking, this probably contributes to the observed high levels of diarrhoeal disease.

Globally, grasslands are affected by climate change and unsustainable management practices which usually leads to transitions from stable, degraded and then to desertification. Spatial vegetation patch configurations are regarded as key indicators of such transitions. Understanding the relationships between this grass-land vegetation and its environment is key to vegetation restoration projects. Spatial vegetation patch patterns were chosen across different soil and topographic conditions. Patch numbers, perimeter, and cover of each patch were measured along transects of each patch type. Using field surveys and multivariate statistical analysis, we investigated the differences in vegetation biomass and distribution and soil properties of four typical alpine plant species patches along with a range of environmental and topographic conditions. It was found that topographic conditions and soil properties, particularly soil moisture explained most of the variation in spatial patch vegetation characteristics and thus control vegetation restoration in the alpine grassland. The Kobresia humilis, Blysmus sinocompressus and Iris lactea patches under the drylands recorded small patch sizes, large patch numbers, low connectivity, and large total perimeter per unit area. Generally, species within the high moisture sites recorded small patch numbers, a large fraction of vegetation cover and a small total perimeter per m2. Patches in limited soil moisture areas recorded patch configurations indicating they are unstable and undergoing degradation and therefore need urgent restoration attention to forestall their further degradation and its resultant effect of desertification. These results would provide quantitative easy-to-use indicators for vegetation degradation and help in vegetation restoration projects.

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Vegetation patchiness is common in degraded grasslands. Vegetation patchiness enhances the spatial variability of grassland soil organic carbon and total nitrogen. Stripped vegetation patches have a great impact on ecosystem carbon (C) and nitrogen (N) storage. Using field surveys, we examined the effects of patches on the ecosystem carbon and nitrogen storage of four typical alpine grass species patches (viz: Leymus secalinus, Koeleria pers, Stipa aliena, and Leontopodium nanum). The results indicated that ecosystem C, N, and respiration were significantly higher in intact vegetation patches than in stripped vegetation patches. Also, stripped vegetation patches recorded higher quantities of soil gravel content than the intact patches. In Leymus secalinus and Koeleria pers species patches, soil approximately contributed about 62% and vegetation about 38% to ecosystem carbon and nitrogen storage, whereas in Stipa aliena and Leontopodium nanum species patches, close to 80% of ecosystem carbon and nitrogen were found in the soil while close to 20% were stored in the vegetation. Soil total phosphorus (TP), total potassium (TK), available phosphorus (AP), soil microbial biomass carbon (MBC), and soil microbial biomass nitrogen (MBN) were higher in intact vegetation patches than in the stripped vegetation patches. Ecosystem carbon and nitrogen were observed to have a significant correlation with soil gravel content and vegetation productivity. Stripped vegetation patches resulted in decreased plant biomass input and an increased rate of soil erosion. We conclude that grassland patchiness resulted in the decline of ecosystem carbon and nitrogen storage due to a reduction in vegetation input and an increase in soil erosion. Grasslands are likely to have a higher possibility of serving as a C sink if the input of organic matter exceeds its output via sustainable management practices.