Bramble and maqui: how invasive plants colonized 80–90% of the native forest
Rubus ulmifolius (bramble) and Aristotelia chilensis (maqui) have displaced endemic flora from 80 to 90% of the island's forest. Projects led by CABI and CONAF work on active restoration of species unique to the world.
The Juan Fernández archipelago holds one of the most singular botanical ecosystems on the planet: 60% of its flora is endemic, meaning it exists nowhere else on Earth. Yet that extraordinary biodiversity now faces its greatest crisis: two invasive plants have colonized 80 to 90% of the original forest area, displacing native species with devastating efficiency.
The protagonists of the invasion
European bramble (Rubus ulmifolius), introduced unintentionally, forms impenetrable mats that block light and space for native forest regeneration. Maqui (Aristotelia chilensis), a species native to mainland Chile, behaves similarly: it grows fast, produces abundant fruits dispersed by birds, and covers the understory before endemic trees can establish. Together, these two species have transformed the landscape of Robinson Crusoe in just a few decades.
What is lost
Direct victims include unique genera such as Dendroseris — giant lettuce trees — Robinsonia and Rhetinodendron, all endemic to the archipelago. Many of these species have such small populations that any further impact risks permanent extinction. The disappearance of native forest also drags down the fauna that depends on it: the firecrown, endemic pollinator insects, and birds that nest only in specific tree species.
Active restoration
The project led by CABI (Centre for Agriculture and Bioscience International) together with CONAF works on two simultaneous fronts: physical and biological control of invasives, and propagation and replanting of native species in nurseries located on the island itself. The program includes searching for specific biocontrol agents for bramble — insects or pathogens that affect it without harming native flora — a strategy that has worked successfully on other islands worldwide.
The scale of the problem is enormous, but the knowledge exists. What is missing is time, funding, and sustained political will. The flora of Juan Fernández has nowhere else to go.