Tackling the Last Frontier: The Lower Orange River

What is the composition of riparian vegetation along the Lower Orange River? How was it affected by the construction of large dams in the 1900’s? These are some of the questions the Arid Lands Node, in collaboration with SANParks and the University of the Witwatersrand, are looking to answer with the Lower Orange River Riparian Project (LORRP). The Orange River system is of great economic importance nationally, and in particular for the Northern Cape Province. Although the negative effects of river damming have been studied globally, the Orange River is so unique in many ways that extrapolations likely do not apply to it.

Due in part to an altered hydrology through increasing water infrastructure development and extraction, and surrounding development pressures, much of lower Orange riparian zone had recently been declared a threatened ecosystem. Yet, despite this declaration, vegetation surveys along this section of the river are non-existent, apart from work by Werger & Coetzee (1977) and Bezuidenhout (1996) in the (now much larger) Augrabies Falls National Park.

Why had these surveys not been done? SAEON’s Marco Pauw, along with fellow field technician Tshililo Ramaswiela and intern Stefan Goets, soon found out when they did the first surveys for LORRP in September and November 2017. Apart from the logistical challenges of reaching remote locations and packing enough supplies with their equipment, the three encountered impenetrable dense and thorny vegetation, dangerously steep banks, and extreme weather conditions. Their reward for crawling through small gaps, ignoring stingy thorns and insect bites, and bearing the heat and paddling against strong headwinds? Doing ground-breaking work in one of the most beautiful landscapes in South Africa, if not the world. They also got to see some unique plants and creatures along the way, such as a water monitor raiding bird nests on rocks in the river, rosy-faced lovebirds in their natural environment, and getting a glimpse of the massive root systems of trees growing in this harsh environment. Marco is also doing this work for his PhD and will write regular updates on the project’s progress here.