Spatial Distribution of Benthic Macro-Invertebrates as Indicators of Anthropogenic Pollution in Makupa Creek, Mombasa

Coastal ecosystems, including lagoons, creeks, and estuaries, are increasingly threatened by anthropogenic pollution arising from urban, industrial, agricultural, and atmospheric sources. These inputs degrade water and sediment quality, resulting in biodiversity loss, disruption of aquatic food webs, and potential risks to human health. Benthic macro-invertebrates are valuable bio-indicators of environmental quality because they integrate the effects of contaminants over time. This study assessed the spatial distribution of benthic macro-invertebrates in Makupa Creek, Mombasa, to evaluate the influence of anthropogenic disturbances on benthic community structure. Results indicated that sewage effluents from domestic and industrial activities, leachates from solid waste disposal sites, and restricted hydrological exchange significantly influence benthic macro-invertebrate assemblages compared with those found in relatively pristine coastal environments. Analysis of Similarity (ANOSIM) revealed no significant differences among sampling stations (Global R = 0.018, −0.026, and −0.196; p > 0.05), suggesting the presence of several common species across the study area. However, Similarity Percentage (SIMPER) analysis identified Limnodriloides barnardi, unidentified nematodes, Mesanthura catenula, Heterodrilus jamiesoni, Olavius geniculatus, Aktedrilus monospermathecus, unidentified polychaetes, and Lucifer chacei as the taxa contributing most to community dissimilarity among stations. The findings highlight the ecological importance of estuarine and coastal wetlands as biodiversity hotspots that support energy transfer within aquatic ecosystems and mitigate the impacts of land-based disturbances on aquatic and benthic environments. Conservation and effective management of these ecosystems are therefore essential for maintaining ecological integrity and ecosystem functioning.