Himalayan balsam (Impatiens glandulifera) is a non-native annual plant that was introduced into parts of Europe during the mid-nineteenth century as an ornamental plant for parks and gardens.
This plant species was first recognised as an invasive species and a threat to ecological stability in the 1930’s. However, since then the problem has escalated and is now of international concern, due to its negative impact on ecosystem biodiversity. This is primarily due to its ability to out-compete and overcrowd native vegetation. Himalayan balsam has now naturalised in many countries, resulting in a shift in management strategies from attempting to remove the invasive plant, to limiting its territory and further spread.
Alan Gange, Amanda Currie & Nadia Ab Razak (Royal Holloway, University of London), Carol Ellison, Norbert Maczey & Suzy Wood (CABI ) and Robert Jackson & Mojgan Rabiey (University of Reading) discuss the threat of invasive species to biodiversity, including the biological control of Himalayan balsam
Invasive species are one of the main threats to biodiversity across the world, being second only to habitat destruction in causing biodiversity decline. In the UK, they cost the economy £1.7 billion annually, through costs of control, losses to agriculture and damage to infrastructure.
Building on CABI research into the biological control of Himalayan balsam (Impatiens glandulifera) using a rust fungus (Puccinia komarovii var. glanduliferae), a Natural Environment Research Council (NERC) funded collaboration between Royal Holloway, CABI and the University of Reading is investigating the role of the microbial community associated with the plant and how these microbes may be exploited to enhance biocontrol efficacy and aid in the recovery of invaded sites. It is hoped that the findings of the study may be applicable to biocontrol programmes more widely.
Himalayan balsam is one of the UK’s most widespread invasive weed species, colonising river banks, wasteland, damp woodlands, roadways and railways. Research by CABI scientists has shown local invertebrate biodiversity is negatively affected by the presence of Himalayan balsam. This leads to fragmented, destabilised ecosystems, which has serious consequences on processes and functioning, and complicates habitat restoration unless remedial actions are implemented.