Invasive plants like Japanese knotweed and Himalayan Balsam are destroying unique flower ecosystems across the world
- Japanese knotweed seen as a ‘super invader’ destroying UK’s unique mix of flora
- Another offender in Himalayan balsam, an invasive weed of riverbanks, ditches
- They can upset an area’s flora leading to a ‘net loss of global floristic uniqueness’
- Researchers said the UK was hard hit by the phenomenon with high level decline
Invasive plants from other parts of the world such as Japanese knotweed are destroying Britain’s unique mix of flora, say researchers.
The knotweed is seen as a ‘super invader’ capable of colonising new territory and displacing native species, according to the study.
Another offender is Himalayan balsam which was introduced here in 1839 and is now an invasive weed of riverbanks and ditches, where it prevents native species growing.
Such plants can sometimes enrich ecosystems but usually upset a region’s particular mix of plants, leading to a ‘net loss of global floristic uniqueness’, said researchers at the University of Konstanz in Germany.
Invasive plants from other parts of the world such as Japanese knotweed are destroying Britain’s unique mix of flora, say researchers
The ‘super invaders’ are causing the flora in even regions with clear geographic separation to become increasingly similar.
For the paper, published in Nature Communications, the researchers studied 658 regional floras from nearly all parts of the world.
Study author Dr Qiang Yang said the UK is particularly hard hit, with a ‘very high level of decline in floristic uniqueness’.
Wild flowers growing in one country are becoming similar to those grown elsewhere, something that was not the case previously, the research found.
The researchers from the University of Konstanz in Germany said ‘super invaders’ – which are highly effective at colonising new territory and displacing native species – are causing the flora in even distant regions with clear geographic separation to become increasingly similar.
To assess how ‘unique’ each region was, researchers looked at the number of plant species a region shares or does not share with other regions, and the degree to which plant species are related to each other.
Another offender is Himalayan balsam which is an invasive weed of riverbanks and ditches (pictured, volunteers remove the plant from the River Lea, London)
Factors that contributed to the loss of floral uniqueness include having a similar climate.
One example was Eucalyptus – originally from Australia, but now grown in many countries with similar warm climates.
‘The more similar two regions are in terms of climate, the more likely it is that a plant from one region will succeed in establishing itself as a naturalised species in the other region, once geographic barriers have been crossed.
‘In a sense, plants from a region with short climatic distance to their new habitat are “climatically pre-adapted”,’ Dr Qiang Yang, the lead author of the study, said.
Dr Mark van Kleunen, Professor of Ecology in the Department of Biology at the University of Konstanz and senior author of the report, said: ‘These effects are now evident even in the most remote corners of the world.
‘Unless more effective protective measures are taken to counter the ongoing spread and naturalisation of alien plants in the future, they will continue to destroy the uniqueness of our ecosystems – making the world a less diverse place.’