Bacterial diversity in relation to anthropogenic activities: a case study of Kibale national park wetlands, Uganda

Abstract

Bacterial diversity refers to the vast variety of bacteria in an ecosystem which function in maintaining wetland ecosystem health through nutrient recycling for the trophic status and building symbiotic relationships with other organisms. This system is being threatened in many wetlands of Uganda as a result of an increase in anthropogenic activities such as agriculture and urbanization. The study aimed to examine bacterial diversity in relation to the anthropogenic activities in Kibale National Park (KNP) wetlands. A cross-sectional design was used in data collection. Land Use and Land Cover (LULC) changes were determined in ArcMap 10.8 through unsupervised classification of high-resolution images of twenty years for 2003, 2013 and 2023. The level of wetland degradation was determined using the Anthropogenic Activity Index (AAI) score. Temperature, dissolved oxygen, electrical conductivity and pH were measured with an electrical meter. Meanwhile, composition of bacteria from 50 water samples was determined using Environmental Deoxyribonucleic Acid (eDNA) technologies and metabarcoding. The forest cover of KNP reduced from 78% to 42% in the 20 years while farmland, grassland and built-up all significantly increased. Generally, there was a significant difference in physicochemical properties and AAI between inforest and outforest wetlands of similar types. Outforest wetland were more degraded then inforest wetlands. The dominant bacterial phyla in all wetlands were Proteobacteria and Actinobacteriota where the former dominated inforest wetlands and the later dominated outforest wetlands. Bacterial diversity significantly varied between inforest and outforest wetlands of the same type except for swamps where they were similar. As a result of differences in environmental conditions, bacteria composition was richer in intact wetlands than in degraded wetlands of similar types. Conditions in degraded wetlands abundantly harboured harmful species such as Arcobacter cryaerophilus and those known to thrive in polluted waters like Thiothrix nivea. Reduction in forest cover led to increased anthropogenic activities around the wetlands which altered their physicochemical properties that then negatively influenced their bacterial diversity. The wetlands of KNP should therefore be restored and protected through science backed interventions and policies for improved ecosystem health. This would benefit both the community by providing clean-safe water and improved sanitation as well as saving the biodiversity in these wetlands from damage.