Alien plants in South Africa consume more water than indigenous vegetation, particularly in dense stands along rivers. This results in a 4% reduction in water availability, a figure that could escalate exponentially if these plants spread unchecked. The uncontrolled growth of alien plants has further negative side effects, including the loss of rare species, displacement of indigenous populations, increased fire intensity, soil erosion, interception of catchment runoff, and detrimental impacts on biodiversity and the functioning of aquatic ecosystems.

To promote the resilience of tributaries in the Upper Breede River as ecological corridors and providers of ecosystem services, critical interventions such as alien clearing and rehabilitation projects are essential. Ecosystem services are recognized as vital to society and hold significant economic value. The benefits of restoring natural capital include improving water security, diluting pollution, recharging groundwater, and supporting ecological resilience. Therefore, alien clearing and rehabilitation projects in the Upper Breede River region are crucial for restoring natural capital.

Due to the invasion of woody alien plants and the subsequent disruption of natural fire regimes, many majestic indigenous trees and shrubs that once populated the forested banks of the Breede River—such as the Breede River Yellow Wood (Podocarpus elongatus), Wild Olive (Olea europaea subsp. africana), Wild Almond (Brabejum stellatifolium), and Palmiet (Prionium serratum)—have all but disappeared from the system. The project aims to grow these plants in the Worcester Field Reserve nursery to reintroduce them into their native habitat. These reintroductions occur as part of a structured project and also through landowners who purchase the plants to establish them in their campsites along the riverbanks.

The reintroduction of these indigenous trees provides competition for returning alien plants and enhances the functional diversity of the riparian zone. Without this active intervention, the ecosystem will not achieve the level of ecological resilience necessary to thrive independently. Today, there are few places where these trees are cultivated, and without a concerted effort to re-establish them, they will not be able to return to their original habitats.