A view of the Mawddach Estuary on a clear spring day with woodland lining the shores.
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One of the National Park’s major challenges 

Invasive species are a significant problem worldwide, and natural habitats are dying out as a result. Native plants are also dying out, along with the animals that have evolved to live with them. 

Impact of Invasive Species

Biological systems are in constant competition for nutrition, water and light. Introducing non-native species to these systems can make them more competitive. 

Other species cannot compete against these new, more resilient and robust species. Some of these species can become invasive species that destroy other plants. 

Rhododendron ponticum is one of Eryri’s most harmful invasive species. Without intervention, Rhododendron ponticum could cause considerable problems in the National Park, including the decline of wildlife habitats. 

Rhododendron Ponticum
Rhododenron ponticum
Very few plants can live alongside Rhododendron, and it is poisonous to many animals. Rhododendron ponticum has extremely effective survival methods. One bush can produce about a million seeds. Successful germination of the seeds requires particular conditions, but a single established seed from a bush can lead to propagation on a massive scale.
Himalayan balsam
Himalayan Balsam
Himalayan Balsam has become so widespread that it is not possible to eradicate it entirely at this time. The species has pods full of tiny black seeds. When someone brushes against these pods, they explode, allowing the seeds to disperse.
Japanese knotweed
Japanese Knotweed
In recent years, Japanese Knotweed has become a notorious species, mainly for its remarkable ability to spread. This species is so troublesome that it is illegal to let it grow in the wild. Japanese Knotweed does not spread through its seeds but rather through the rhizomes at the roots of the plant.
Invasive Species

An overview of invasive species.

Over the past century, Rhododendron ponticum has spread over 2,000 hectares.
Most invasive species came to Britain as plants to grow in gardens.
Japanese Knotweed is an invasive species notorious for its stubborn roots that allow the weed to spread easily.
An area of ​​400 rugby pitches has been cleared of Rhododendron ponticum

Responding to the challenge

Although it is not illegal to grow species considered invasive in gardens, it is illegal to cause the spread of these species to ‘wild’ places. 

Great care needs to be taken when disposing of garden waste that may contain seeds or roots of invasive species. 

In the case of Japanese Knotweed, the roots of this species can easily be carried on the soles of shoes or on garden tools. Japanese Knotweed spreads through these roots. 

The National Park Authority and other organisations involved in the management of Eryri have been working together for many years to tackle the problem of invasive species. 

The most popular method of controlling the species is cutting back the plant and using herbicides to kill the plant. The National Park Authority’s conservation team has also been using drones to explore large areas of land for new growth of species such as Rhododendron ponticum. 

The Authority’s work

The National Park Authority has a duty to protect Eryri’s wildlife and landscapes. 

The Authority is leading the way internationally in terms of tackling invasive species, pests and infections. A large part of the Authority’s work involves organising meetings and conferences, offering grants and managing the invasive species in our woodlands.