An annual national event to raise awareness of the impacts of invasive non-native species. Aiming to highlight some of the simple things that everyone can do to prevent their spread, and highlight some amazing work being done across the UK and Ireland to protect the environment and reduce the impact of invasive species.
But what are invasive non-native species?
They are plants, animals or any other organism that are introduced to an ecosystem and cause harm to the environment, economy or human health. These species often spread rapidly and outcompete native species. The UK has experienced its fair share of invasive species, which pose a threat to the country’s biodiversity.
Some of the common plant species found in UK were introduced for ornamental purposes. Plants such as Japanese Knotweed, Rhododendron and Himalayan balsam alter the soil conditions and reduce the habitat available for wildlife.
Japanese knotweed was introduced in the 19th century as an ornamental plant and is one of the most invasive plants in the UK. Able to grow up to 20cm a day and can damage concrete, tarmac and even buildings making it difficult to eradicate and can take years to completely remove. Also introduced in the 19th century, Himalayan balsam spread to riverbanks from gardens and outcompetes native species. These species create a monoculture whilst others like Giant Hogweed can cause severe skin burns and blindness.
Other invasive plant species you may see in the UK are
Rhododendron, a plant originally from the Iberian Peninsula, was introduced in 1763 for use in gardens in Great Britain. However, it has now become an invasive species and is present in almost every area of the country. This plant blocks out light, preventing other species from growing beneath it, and carries diseases that can be fatal to native trees.
Water primrose is a freshwater weed from South America that was introduced to Europe for its yellow flowers. In France, it has become widespread and blocks waterways, takes over ponds and lakes, and causes flooding. Although it is only established in a small number of sites in England and Wales, if it were to spread widely, it would cost millions to manage. The Environment Agency is working to eradicate existing populations, and gardeners are asked to avoid dumping aquarium or pond plants in the wild.
American skunk cabbage, another invasive plant from North America, was introduced in 1947 by ornamental plant collectors who admired its flowers. It has become established in some wet woodlands, where it crowds out native plant species and emits a strong skunk-like odour.
Floating pennywort, a North American aquatic plant, was first recorded in the wild in Great Britain in 1990, having spread from garden ponds and aquaria into the wild. It can grow up to 20cm in a day, quickly covering whole water bodies, harming aquatic wildlife by blocking out light and reducing available oxygen, and interfering with recreational activities like angling and boating.
Pitcher plant, a carnivorous plant from North America, is a threat to bog communities as it reduces the cover of native plant species, including mosses, and impacts insect communities. Volunteers from the New Forest Non-native Plants Project are helping to clear this plant from the New Forest.
With over half the plant species found in the UK are non-native now is the time to act. From removing them from your garden to joining work parties that remove them from your local green spaces.