Influence of Water Quality on Macroinvertebrate Diversity in Nairobi River, Nairobi City County, Kenya
| dc.contributor.author | Ndichu, Naomi Nyambura | |
| dc.date.accessioned | 2024-09-26T06:14:45Z | |
| dc.date.available | 2024-09-26T06:14:45Z | |
| dc.date.issued | 2024-06 | |
| dc.description | A Thesis Submitted in Partial Fulfilment of the Requirements for the Degree of Masters in Biogeography (Department of Geography) In the School of Humanities and Social Sciencies of Kenyatta Universitty, June 2024 | |
| dc.description.abstract | Globally anthropogenic activities have resulted in water pollution threatening aquatic life. This study aimed to analyze the influence of water quality on macroinvertebrate diversity. The study's specific objectives were: i) to analyze selected physical-chemical quality of water ii) to assess the abundance and diversity of macroinvertebrates iii) to establish the relationship between macroinvertebrate diversity and water quality and iv) to determine the effect of rehabilitation on macroinvertebrates' diversity along Nairobi River. Data on the physico-chemical parameters of water and the type and number of macroinvertebrates were determined in the field and in the phytotherapeutic laboratory using laboratory standard procedures. Data collection methods also included direct observation and interview guides. Data analysis was done using: ANOVA, T-test, Shapiro-Wilk test, multiple regression tests, and Pearson's correlation in SPSS version 29 and descriptive data analysis was done in Excel. Study results indicate a significant variation in water quality parameters between rehabilitated and non-rehabilitated zones (P< 0.05) during the dry days. However, the wet days' results indicate no significant differences in water quality among sample plots (P > 0.05). The number of macroinvertebrates was not significantly different (P > 0.05). Using Pearson's correlation, a significant negative relationship between macro- invertebrates’ diversity with nitrates and phosphate levels was established (r = -0.863 and -0.603, P < 0.05). Although not statistically significant at P ≤ 0.05, a negative relationship was found between macro invertebrates' diversity with water temperature, electrical conductivity, total dissolved solids, and water turbidity. Dissolved oxygen and pH positively correlated with macroinvertebrates' diversity. Species evenness was significantly positively affected by the levels of nitrates in the waters (r = 0.360, P = 0.043). Other positive relationships with the species' evenness were recorded in water, turbidity, and phosphates in water (P > 0.05). Electrical conductivity (r = 0.360, P = 0.043) had a significant positive correlation. Total dissolved solids also increased the number of macroinvertebrates. The diversity of macro-invertebrates in the mean rehabilitated area (310) was not significantly different from the non-rehabilitated area (mean 222.18), t = 0.478, P = 0.636. Species evenness in the rehabilitated (middle course) compared to the non-rehabilitated area (upper and lower courses) showed a significant difference, t = 2.35, P = 0.0255). Water pH and Dissolved Oxygen were slightly high in the rehabilitated area. Electrical conductivity, total dissolved solids, and turbidity were high in non-rehabilitated areas. Nitrates and phosphates were significantly higher in the non-rehabilitated area than in the rehabilitated area (P < 0.05). The study found that 25% of the respondents said that the water quality had deteriorated while 75% reported problems to human as well as macroinvertebrates. The predominant parameters in the study area were dissolved oxygen, nitrates, and phosphates. Macroinvertebrates were more abundant and diverse in the middle course. The predominant parameters had a significant effect on the diversity and abundance of macroinvertebrates where oxygen had positive correlation and phosphates and nitrates had negative correlation with macroinvertebrates’ diversity and abundance. Rehabilitation was noted to have a positive impact to aquatic life since diversity was higher in the rehabilitated areas. Measures to prevent pollution such as proper disposal of wastes, imprisonment, and penalizing those who will be found polluting the river should be enhanced. More research should be done to establish distribution of other species in the river, their adaptability as well as identifying the extinct species. Citizens should be educated on the impact of pollution on aquatic life. Rehabilitation activities should be extended to cover larger or the whole section of the river. The study findings will make people living along the river to be aware of the harm caused to biodiversity in the water. | |
| dc.description.sponsorship | Kenyatta University | |
| dc.identifier.uri | https://ir-library.ku.ac.ke/handle/123456789/28872 | |
| dc.language.iso | en | |
| dc.publisher | Kenyatta University | |
| dc.title | Influence of Water Quality on Macroinvertebrate Diversity in Nairobi River, Nairobi City County, Kenya | |
| dc.type | Thesis |