Tackling Invasive Species - Carneddau Landscape Partnership

What are invasive species and how do they impact our environment?

Invasive species are species that can negatively affect native plants and animals.

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

Some species cannot compete against these new, more resilient and robust species and therefore struggle to thrive and in some cases are wiped out from an area entirely.

This can then have a negative impact on animals and insects that evolved to live with them.

What is Himalayan Balsam?

Himalayan Balsam is also an invasive, non-native species that spreads rapidly and causes serious harm to our native habitats including riverbanks and ditches. Himalayan Balsam has large, pink flowers shaped like a bonnet. It is also known as a ‘policeman’s helmet’ because of its appearance. The flowers are followed by hanging, green seed pods. Each plant produces hundreds of seeds each year, which can be projected through an explosive release from the seed pod, causing widespread growth, usually spreading downstream of watercourses. This highly effective method of self-propagation creates dense thickets of Himalayan Balsam up to 2.5m high, leaving little or no space for other native species to compete.

Super spreader

Each plant can produce up to 800 seeds, with the seed pods able to shoot their seeds up to 7m away.

River health

Himalayan Balsam out-competes other important species and weakens riverbanks when it dies back each year, leaving banks bare and prone to erosion. This decreases water quality and increases flood risk in the Autumn and Winter.

Spread by water

Once established in the catchment of a river, the seeds, which can remain viable for two years, are transported further afield by water.

What is Rhododendron Ponticum?

Rhododendron Ponticum is a non-native, invasive species that can grow up to 6m high and has large pink and purple flowers in May and June. It is an introduced species that has spread into woodlands and thrives in damp climates. It outcompetes native plants and significantly reduces biodiversity. This species is difficult to eradicate as its roots can make many new shoots; a single shrub can produce up to a million tiny seeds per year.

Effect on the landscape

Rhododendron blocks sunlight and outcompetes other native plants and trees, which has a negative impacting on biodiversity.

A significant presence

Over the last century in Eryri, Rhododendron has spread over 2,000 hectares and now has a significant presence in the Carneddau area.

Poison

Rhododendron is toxic to most invertebrates and mammals; therefore, it does not support an extensive food chain.

Himalayan Balsam Volunteer Day

Himalayan Balsam

Rhododendron Ponticum

What are we doing?

Having identified priority areas of Rhododendron that have spread in the north areas of the Carneddau, we are working closely with specialist contractors to tackle and eradicate this invasive plant. The process generally takes several visits to physically remove the plant and treat the remaining roots with targeted herbicide via root injection. It can take months, if not years, to fully remove.

We are also working with communities to tackle this increasing problem, ensuring that people feel better equipped and supported to tackle Himalayan Balsam in their local area in the long term. Taking part in practical action ensures that groups can continue to clear local areas beyond the project’s lifetime.

Why is this important?

It is important that the encroaching spread of Rhododendron and Himalayan Balsam is brought under control to stop these plants taking over more native habitats, resulting in significant loss of biodiversity.

If left unmanaged, the increase in invasive species cover will encroach into nationally important areas for nature, including Abergwyngregyn National Nature Reserve and Sychnant Pass.

The uncontrolled spread of invasive species increases exponentially over time. Each year, more and more plants are seeding to larger areas, and this is why invasive species are difficult to control and require intensive intervention to limit their spread.

Planning Invasive Species Control Activities Accredited Training

Volunteer with Snowdonia Society and develop the knowledge and skills to be able to plan community conservation activities relating to the clearance of invasive plant species.

Agored qualification information

Snowdonia Society volunteering events

How can you get involved?

Join a volunteer day through our partners Snowdonia Society

Contact us if you would like more information and support to set up a local invasive species community group.

Join a volunteer day through our partners Snowdonia Society

Contact us if you would like more information and support to set up a local invasive species community group.