Biological Control of Invasive Non-Native Riparian Weeds

Descriptions

Defra has invested in research to support the management of invasive, non-native species (INNS) for several years. It is a key aspect of the GB INNS Strategy, which Defra is committed to delivering under the 25 Year Environment Plan. The Environmental Audit Committee recently recommended a rapid expansion of support for it. This contract will enable us to continue to fund such research to enable cost-effective, long-term and species-specific control of priority INNS plants, which cost Great Britain approximately £2 billion a year by having significant impacts on biodiversity, infrastructure, flooding, the economy and safety. The invasive non-native riparian weeds Japanese knotweed (JK, Fallopia japonica), Himalayan balsam (HB, Impatiens glandulifera), floating pennywort (FP, Hydrocotyle ranunculoides) and Australian swamp stonecrop (ASSC, Crassula helmsii) can have major impacts on invaded water bodies and connected habitats by reducing biodiversity, restricting access, increasing flood risks and impeding transport and recreation. These weeds have also been a key constraint to compliance with requirements of invasive alien species legislation, which specifically names HB and FP as invasive alien species (IAS) of Union concern. They are likely to remain highly problematic for the UK. Due to their proximity to water, the options for conventional control are limited, thus classical biological control using damaging and host-specific natural enemies from the respective native ranges of the plant species can offer a suitable alternative. Since 2011 Defra has funded research into biological control of HB, FP and ASSC under the contract "Assessing the potential for biological control for weeds impacting on Water Framework Directive targets (Biocontrol for WFD weeds)" awarded to CABI. Research for JK, funded initially (2003 onwards) by a consortium including Defra, has been mainly supported by Defra since 2013. The most recent contract "Biological Control of Invasive N