Ecological health assessment of Lukosi River using macroinvertebrate and riparian vegetation indicators in Iringa, Tanzania
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Date
2025-12-30
Journal Title
Journal ISSN
Volume Title
Publisher
Water Institute
Abstract
The health of river ecosystems is increasingly threatened by human activities such as agriculture, urbanization, and
industrialization. This study evaluates the ecological status of the Lukosi River Catchment (LRC) in Kilolo District, Iringa,
Tanzania, using macroinvertebrates and riparian vegetation as bioindicators. We employed a cross-sectional design,
sampling at upstream, midstream, and downstream sites. Macroinvertebrates were collected via the kicking-bottom method
and analyzed using the Shannon–Wiener diversity index and the Average Score Per Taxon (ASPT). Riparian vegetation
was surveyed through belt transects and assessed by species distribution and proportional cover. Fourteen
macroinvertebrate taxa were identified, dominated by water scavenger beetles and snails. Biodiversity was moderate (H′ ≈
1.98). ASPT scores declined spatially: upstream (good quality), midstream (moderate), and downstream (poor), indicating
worsening water quality downstream. The riparian zone was heavily modified: about 58% grasses, 28% shrubs, and 14%
trees, reflecting human disturbance and land-use change. The results reveal progressive ecosystem degradation along the
river, strongest downstream, likely driven by pollution and catchment alteration. These results call for integrated
catchment management policies, stricter land-use regulation, and community-based riparian restoration programs to
enhance water quality, biodiversity, and long-term ecological resilience of the LRC.
Description
Journal of Water Resources, Engineering, Management and Policy, pp. 204-222
Keywords
Ecological health, Lukosi river Catchment, Macroinvertebrates, Riparian vegetation, Bioindicators
Citation
DOI:https:doi.org/10.56542/wi.jwempo.v2.i2.a13.2025