The non-native plant, Rubus niveus, is spreading quickly, and destroying the delicate ecosystem of the archipelago, which causes problems for farming and food supply. On 25 August two science organisations from the United Kingdom teamed up with the Galapagos National Park Directorate to work with farmers on weeding out the invader.
Their strategy is to find suitable biological control agents, such as insects or diseases that would keep the plant in check. Once selected and introduced, these agents would make management of the blackberry easier and less expensive for farmers than weeding, helping to recover previously abandoned agricultural areas.
Farmers are expected to play a crucial role, says Carol Ellison, the project’s lead scientist for the Centre for Agriculture and Biosciences International (CABI), one of the UK partners.
“Finding a solution to manage the blackberry would help make the community on the Galapagos more self-sufficient.”
Rachel Atkinson, Charles Darwin Foundation
“Farmers see biological control in action on their farms every day — such as natural enemies eating insect pests — so they were comfortable with the concept,” she says. “They are very supportive of the project.”
Originally from Asia, the blackberry was introduced for farming on Santa Cruz Island in the late 1960s. But after being carried from island to island by trade and travellers, the species has invaded all vegetation types, from grasslands to forests, forming dense thickets up to four metres high. Its aggressive growth displaces native plants, especially forests dominated by Scalesia, also known as daisy tree, which has already been decimated to less than 1 per cent of its original cover due to various environmental threats, the researchers warn.
Watch Rachel Atkinson discuss the threat of invasive species on the Galapagos islands
The blackberry has also caused serious economic problems for farmers, as it kills their harvests and is hard to control by weeding due to its high seed count. In some areas, it has forced them to abandon agricultural land.
The plan now is to give farmers the oversight over releasing and nurturing biological control on their land. Ellison estimates that it would take five to ten years for any natural enemy to have a significant impact on berry growth.
The goal is to reduce prevalence of blackberry to a manageable level rather than to fully eradicate it. An earlier study, carried out by Ecuadorian scientist Jorge-Luis Renteria and colleagues, found that if just 40 per cent of Galapagos land were home to the berry, other plant and animals could thrive. “This management target could act as a guide for the development of any biological control agent,” Renteria said in an article published in PLOS One.
“Finding a solution to manage the blackberry would help make the community on the Galapagos more self-sufficient and reduce the need to send produce from the mainland,” says Rachel Atkinson, a researcher at the Charles Darwin Foundation, the other UK project partner. She adds that reducing food imports is crucial to preserving the archipelago’s environment, as trade and shipping are pathways for the introduction of further pests.