Lorraine Williamson
A fast-spreading invasive reed species, Arundo donax, is becoming a major environmental concern across the province of Málaga. Native to the eastern Mediterranean, this giant reed is now disrupting river ecosystems, blocking waterways, and causing damage along the coast.
Heavy rainfall and strong winds this winter have worsened the situation. Washed-down plant debris has clogged dams, collected at bridges, and been deposited along the beaches of Málaga, creating a costly mess for coastal councils to clear up.
Biodiversity under pressure
The reed grows aggressively along riverbanks, displacing native species such as oleander and tamarisk. This rapid colonisation leads to a sharp drop in biodiversity, as native plants struggle to compete. The regional government, Junta de Andalucía, is working with environmental scientists to identify effective ways to manage the invasion.
Experts say the spread of Arundo donax across Málaga is not only an ecological problem but also a hydrological one. Dams like Casasola and El Limonero have seen reduced discharge capacity due to blockages. This raises the risk of flooding during storms, especially when large clumps of reed get caught under bridges.
Removing the reed is no easy task
Eliminating the plant is proving extremely difficult. Arundo donax produces an allelopathic chemical—one that suppresses the growth of surrounding vegetation. This chemical advantage makes it hard for native plants to return, even after clearance.
Specialists recommend a combination of nearly manual removal methods and immediate replanting with native species. Establishing natural plant barriers along riverbanks is another strategy, designed to prevent re-infestation and stabilise the ecosystem.
Exploring potential uses
Despite the difficulties, some are looking into whether the reed could be repurposed. Its fast growth and fibrous structure make it a candidate for biofuel or as material for garden screens. So far, however, these initiatives have yet to provide viable commercial alternatives or reduce the spread of the plant.
For now, the focus remains on containment and ecological recovery. With climate change likely to bring more extreme weather, the risk posed by Arundo donax will remain high unless effective control measures are implemented.
Also read: Tarifa turns invasive seaweed into energy and fertiliser with innovative project