… as knotweed drives out our native plants

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.

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’.