International partner, CAB International, plays key role in the fight against invasive blackberry

CDF Scientist Heinke Jäger and Harry Evans from CAB International collecting blackberry samples

Ever since the Galapagos Islands were discovered in the 16th century, alien species have been introduced to the archipelago as a direct result of human activities. Plants are no exception.

Blackberry (Rubus niveus) is the worst plant invader in Galapagos, causing serious problems for species biodiversity and agriculture. Blackberry invades all vegetation types in the wetter parts of the islands, forming dense thickets up to 3 metres tall which have the potential to displace native plant communities such as the unique Scalesia forests.

Blackberry originates from India and was introduced to Santa Cruz in 1968 and later also to San Cristóbal. The plant has become invasive in these inhabited islands, as well as on Isabela, Floreana and Santiago, covering more than 30,000 ha of land area.

Charles Darwin Foundation (CDF) scientists, in coordination with the Galapagos National Park Directorate (GNPD) and other local and international collaborators, are prioritizing research into preventing further spread of blackberry within the archipelago.

The GNPD has been working for many years to control blackberry by cutting off stems and applying herbicides to the regrowth. However, due to the vigorous regeneration and long-lived seed bank of blackberry, success has been limited and control measures are expensive. Additional management strategies are being investigated and one of them could be biological control.

Biological control is a tool used worldwide in the battle against widely-distributed invasive species. The biological control agent is a natural pest found in the native range of the introduced species (usually an insect or a fungus) that only attacks the target species for control, weakening it and reducing its impact.

The fight against blackberry involves many international partners, including CAB International (CABI), based in the United Kingdom. CABI has a worldwide reputation for using scientific expertise to solve problems in agriculture and the environment. Harry Evans, recently described as “a CABI globe-trotting botanical fixer” visited Galapagos in July to provide his expertise.  A specialist in biological control, Harry, and staff members from CDF and GNPD, collected blackberry leaves from Santa Cruz, San Cristóbal and Floreana for subsequent molecular analysis in the UK. The samples will be analyzed to determine the exact geographic origin of the Galapagos blackberry. The next step will be to search for its natural enemies in India (the native range) which could serve as potential biological control agents for blackberry in Galápagos.

In September 2014, CDF Executive Director Swen Lorenz, travelled to the CABI headquarters in Oxfordshire, UK, to discuss this and future collaborations with Carol Ellison, the lead scientist on this project. In addition to blackberry research, we are also currently working together on an investigation into a potential biocontrol agent for the invasive quinine (Cinchona pubescens), working alongside the GNPD.

Swen Lorenz and CABISwen Lorenz visiting CABI, UK

A successful biological control agent will keep the costs of weed control significantly lower and also keep blackberry in check on all sites where present. Thus, it will not only reduce the cost of management for the GNPD and farmers, but also allow the recovery of native vegetation and the subsequent release of agricultural areas for cultivation.

The first steps of this project will be financed by the ‘Fondo para el control de Especies Invasoras de Galápagos’ (FEIG). Since the introduction of a biological control agent in Galapagos can pose many risks to the native flora, rigorous testing of the possible impacts on non-target species have to be carried out and will take between 5-10 years to complete. This also includes testing for possible impacts on related cultivated species, like roses on mainland Ecuador.

We are hopeful of a biological control solution to blackberry due to our previous successes in controlling the cottony cushion scale in Galapagos by introducing the Australian ladybug as a natural enemy. Innovative science and collaborations with local and international partners will once again provide the answer!

The Invasive Plants project is carried out in collaboration with the DPNG, the Biosecurity Agency, the Agriculture, Livestock, Aquaculture and Fishing Ministry and CABI, UK. The project is possible thanks to funding support by Galapagos Conservancy, and the Galapagos Invasive Species Control Fund. The Galapagos National Park Directorate provides in kind support.