Macroinvertebrate and Fish Assemblages as Indicators of Wetland Modification within the SGR Footprint

Abstract

The wetlands outside of conservation areas are threatened by human activities. Tanzania is currently constructing a standard-gauge railway (SGR) from Dar es Salaam to Makutupora, which is expected to impact the area’s ecological condition and biodiversity. Monitoring and preserving these areas’ integrity and ecosystem services require cost-effective tools. This study investigated whether macroinvertebrates and fishes could indicate predictable changes due to construction activities. Using a modified standardized kick-net method and the Fish-based Assessment Method for Ecological Status (FEME), we collected macroinvertebrates at 13 wetlands and fishes at eight selected wetlands. Despite varying degrees of modification, all wetlands supported biodiversity, hosting macroinvertebrates from ten orders and 22 families, and 1139 individual fishes from 23 species, with Tilapia niloticus and Astatotilapia spp. being the most abundant. Both macroinvertebrates and the fishes appeared to reflect the wetlands’ modification levels, suggesting their potential as reliable indicators for assessing human impacts on wetlands, including those affected by SGR construction in Tanzania.