Gilbert Kosgei
University of Nairobi / Kenya Wetlands Biodiversity Research Group
An MSc in Biology of Conservation student and a member of KENWEB. Has wide experience in fish biology. Has also participated in wetlands monitoring initiatives and as such got exposed to biomonitoring initiatives thus the current project.
Macroinvertebrates have been key indicators of changes in physical and chemical Rivers and streams flowing through semi-arid areas of Kenya fluctuate seasonally in water quantity and quality. Such areas also experience high water demand for humans, agriculture, livestock and wildlife. There is need to effectively conserve water resources and monitor changes in quantity and quality.
This presentation will discuss results from a study of ecological responses of aquatic organisms as bio-indicators of the impacts of land use and water quality changes in rivers Burguret and Nanyuki in Kenya. The effects of various land and water uses on water quality and quantity in upper, mid and lower sections these streams will be compared.
Assessment of land use, vegetation cover assessments, physico-chemical parameters of water and composition of aquatic invertebrates have revealed the effects of deforestation, crop cultivation, urban settlements, livestock ranching and wildlife conservation on aquatic ecosystems. Land use characterization as forest, mixed use and conservation was too broad to pinpoint any direct relationship among physical-chemical parameters and biological data.
In the forested valleys of the fast flowing River Burguret, river water temperature and dissolved oxygen differed significantly (F 0.05, 2, 8=7.95 and F 2, 8 =4.68) across all the three sections of the river. In Nanyuki valley, river water dissolved oxygen and temperature varied significantly from upper to the lower sections of the river (F 0.05 3, 11=5.51 and F 0.05 3, 11=3.94). Further, the two rivers were significantly different in temperature (t (19, 0.05) =3.715), dissolved oxygen (t (19, 0.05) =4.713), pH (t (19, 0.05) =1.824) and conductivity (t (19, 0.05) =2.05).
The abundance of major taxonomic orders correlated well with physical chemical-parameters. Pearson correlation test showed that EPT/N ratio was positively and significantly correlated with all the water quality parameters. However, dissolved oxygen was negatively but not significantly correlated at p>0.05. Land use characterization as forest, mixed use and conservation was too broad to pinpoint any direct relationship among physical-chemical parameters and biological data.
