: Professor Timothy Dube, a senior researcher at UWC’s Institute for Water Studies, is part of the team whose recent study examined the impacts of invasive alien plants on groundwater-dependent ecosystems in the Western Cape.

New research from the University of the Western Cape (UWC) has provided critical insights into how invasive alien plant species significantly affect groundwater reserves, with implications for water security in South Africa’s water-scarce landscapes.

The study, conducted by researchers from UWC’s Institute for Water Studies, UWC PhD student Mmasechaba Moropane, and Prof Cletah Shoko from Wits University, and published in the International Journal of Applied Earth Observation and Geoinformation, examined the long-term spread of groundwater-dependent invasive plants in the Nuwejaars catchment in the Western Cape. Using high-resolution multi-date satellite imagery, machine learning and explainable artificial intelligence techniques, the research tracked vegetation changes over 12 years from 2013 to 2024.

The findings showed a marked expansion of invasive species, including Acacia, Eucalyptus and Pinus, which increasingly displaced native vegetation in groundwater-dependent ecosystems. Over the study period, invasive plants expanded from just over 40% to nearly 64% of the monitored areas, drawing heavily on groundwater reserves, particularly during prolonged drought conditions.

Researchers found that the most rapid expansion occurred after the 2015–2018 drought, highlighting how climate stress can weaken indigenous vegetation while favouring deep-rooted invasive species with higher water demands. This shift not only threatens biodiversity, but also reduces groundwater availability for agriculture, ecosystems and communities that rely on these resources.

Importantly, the research demonstrated that targeted clearing of invasive plants had measurable hydrological benefits. Periods of intensified clearing under government-supported initiatives were associated with a partial recovery of native vegetation and reduced dominance of invasive species in some areas.

The findings align closely with South Africa’s Working for Water Programme which aims to control invasive alien plants, improve water security and support ecosystem restoration. By providing long-term, spatial evidence of how invasive plants alter groundwater dynamics, the study offers a scientific basis to strengthen and refine such interventions.

This research underscores the urgent need to integrate invasive species management into national strategies on climate resilience, water conservation and sustainable resource management. The study also highlights UWC’s growing role in producing research that supports evidence-based environmental policy and addresses pressing societal challenges.