Title: Habitat Preferences of Macroinvertebrates in Selected Mount Kenyan Streams (Kenya, East Africa)
Author: Nickson Kipngetich Kiptai
Supervising Institution: BOKU University
Year: 2024
Abstract:
Biomonitoring using benthic macroinvertebrates as indicators of river ecosystem health has gained traction in East Africa, particularly in the context of freshwater management and conservation. This study focused on the habitat preferences of macroinvertebrates in six reference streams on Mount Kenya, sampling eight sites from August 28th to 31st, 2023. The sampling accounted for habitat heterogeneity, including varying flow velocities (pools, runs, riffles) and different substrate sizes, following the AQEM protocol.
Similarity tests and Kruskal-Wallis tests were utilized to investigate the influence of habitat parameters on taxa and Functional Feeding Group (FFG) abundance across different microhabitats. Indicator Species Analysis identified taxa indicative of specific substrate and velocity categories. Habitat Suitability Curves, supplemented by 3D bar charts, were generated to depict the distribution of dominant taxa relative to substrate types and velocity classes.
The study found that substrate size and flow velocity significantly influence the distribution of macroinvertebrate taxa and FFGs. Many taxa showed a preference for either coarse (lithal) or fine substrates. Notably, the low abundance of shredders (1.6% of total abundance) suggests the need for further investigation into functional feeding guilds. Additionally, the bimodal habitat suitability curve of Elmidae and the widespread abundance of Chironomidae across all substrate types and velocities points out to the presence of multiple genera or species in these families, underscoring the necessity for higher taxonomic resolution in future studies.
These findings underscore the critical role of substrate size and flow velocity in shaping macroinvertebrate communities in Mount Kenyan streams, highlighting the importance of detailed habitat characterization in biomonitoring efforts.
Keywords: Kenya, Afrotropic, Afromontane, stream, benthic, macroinvertebrates, bioassessment, habitat preference, suitability, diversity, richness, stream ecology, ecological niche, substrate, sediment, velocity, functional feeding groups, microhabitats, riffles, pools, hydrology, Indicator Species Analysis.