An assessment of the ecological impacts of anthropogenic activities on Palala River, Limpopo, South Africa

The Palala River in the Limpopo Province of South Africa is a non-perennial river that flows through a diverse catchment area including mountainous springs, grasslands, extensive wetlands, the Lapalala Wilderness Reserve, agricultural lands, and human settlements, before it joins the Limpopo River at the Botswana boundary. Human activities across this gradient influence water quality differently along the river’s course, with particular concern during the rainy season. Notably, increased turbidity has been recorded within sections of the Lapalala Wilderness Reserve, while nutrient levels remain poorly studied in regions downstream of agricultural fields and human settlements.This study assessed how various land-use activities affect water quality in the Palala River. Using multivariate ordination and multimetric approaches, it examined environmental variables and macroinvertebrate communities as bioindicators of water quality, using the South African Scoring System (SASS5). Results revealed that areas near human settlements exhibited the highest levels of chloride, total dissolved solids, and electrical conductivity. Increases in these environmental variables corresponded with a decline in macroinvertebrate diversity, taxa richness, and abundance, indicating degraded water quality.The findings underscore the significant impact of anthropogenic activities on river health and highlight the protective role that nature reserves like the Lapalala Wilderness play in maintaining ecological integrity.