Wales’ economy counts £7bn cost of invasive plant species

Himalayan blsam
Himalayan balsam

The total costs in Wales of dealing with invasive species over the years has been put at £7bn by Wildlife Trusts Wales, the collective body for nature trusts throughout Wales.

An inquiry found that Japanese knotweed, Himalayan balsam and rhododendron were having a ‘significant negative economy and environment impact’ on parts of Wales.

See the news story >

Biocontrol of escaped ornamentals

Picking orange balsamA new paper discusses biological control (using natural enemies) of plants that have escaped from gardens and are invading wild habitats in UK. These include Japanese knotweed, Himalayan balsam, Australian swamp stonecrop, floating pennywort, giant hogweed, water fern, rhododendron and buddleja.

Research points to Himalayan balsam as a soil erosion problem

Himlayan balsam root ball with soil
Himlayan balsam root ball with soil

Himalayan balsam (Impatiens glandulifera) promotes soil erosion along watercourses, according to research published in the Journal of Soil Sediments last month (Dec 2013)

Philip Greenwood and Nikolaus Kuhn from the University of Basel show that erosion along riparian zones is statistically greater where Himalayan balsam is present when compared to topographically comparable sites that support natural vegetation. 

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Himalayan balsam distribution data from RINSE

Himalayan balsamVolunteers from RINSE (Reducing the Impact of Non-Native Species in Europe) performed a survey of the River Bure (in the Norfolk Broads), tracking it from source to sea and seeing how many invasive plants such as Himalayan balsam they cam across.

See their website for more information and a map of their results.

Himalayan balsam impact on invertebrates

Himalayan balsam infographic

Himalayan balsam is one of the UK’s most widespread invasive weed species, colonising river banks, waste land, 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.

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New paper published

New paper from the CABI science team:

InvertebrateTanner, R.A., Varia, S., Eschen, R., Wood, S., Murphy, S.T. and Gange, A.C. (2013) Impacts of an invasive non-native annual weed, Impatiens glandulifera, on above- and below-ground invertebrate communities in the United Kingdom. PLoS ONE 8(6), e67271, 13pp. doi:10.1371/journal.pone.0067271