Stop Invasive Species from Destroying Our Celtic Rainforests

Invasive Alien Species have wreaked havoc on the health of our Celtic Rainforests; the globally rare Temperate Rainforest habitats also known as Atlantic Oak Woodlands.

This week (15th - 22nd May) is Invasive Species Week, a world-wide event to raise awareness about the dangers of invasive species, and how to prevent them from damaging our precious ecosystems.

In this blog we will discuss the threats caused by invasive species, and what we can do to save our Celtic Rainforests from further deterioration. We will hear about successful projects in the fight against Invasive Alien Species, and also about what you can do to help us tackle them.

What are invasive species?

"Invasive species" refers to non-native plants, animals, fungi, and micro-organisms, which have been introduced to an area outside their natural range, either intentionally or accidentally. They compete against native species for resources such as water, sunlight and nutrition, they can spread diseases and destroy habitats, as well as cause damage to natural ecosystems, threaten endangered species, reduce biodiversity, reduce crop yields, and of course increase the cost of their control. It has been estimated that the cost to the UK economy of tackling invasives is almost £1.9 billion a year!

Invasive species pose a serious threat to conservation efforts, particularly the species-rich understory flora in our Celtic Rainforests.

Controlling the spread of invasive species and preventing the introduction of new ones is essential in our fight to protect nature. By being vigilant about invasive species, and actively managing the risks associated with their presence, we can protect our natural habitats, ensure biodiversity, and promote a more sustainable ecosystem. By working together and supporting conservation efforts, we can reduce the impact of invasive species and preserve our Celtic Rainforests for future generations to enjoy.

Slider Images: Rhododendron ponticum in flower / American Skink Cabbage by Annette Meyer @Pixabay / Himalayan balsam (c) GBINNS

How are they destroying our Celtic Rainforests?

One of the main invasive species causing significant damage to our Celtic Rainforests is Rhododendron ponticum. Introduced to Britain in the 1700s, and a firm favourite of Victorian Country Houses, it thrives within the gorges and ravines to be found in our Celtic Rainforests, and has become a blight on the land.

Invasive Non-Native Species (INNS) or Invasive Alien Species (IAS) are considered invasive because they out-compete native plants or animals for resources, occupying and taking over their habitat. Rhododendron ponticum is a fast-growing shrub that can reach a height of up to ten feet. One mature plant can produce up to a million tiny seeds each year, which are easily dispersed by the wind. Once their branches touch the ground, they can take root, boosting their strength and distance they can spread, over and over again. This aggressive invader spreads quickly and forms dense thickets that block sunlight from reaching the forest floor. This means that other plants, such as the native Bluebells and Wood Anemone, are unable to grow in areas dominated by the Rhododendron ponticum, and what should be a light, dappled forest floor full of life, turns into dark dank mess.

In addition to this, Rhododendron ponticum can also release toxins into the soil, which makes it harder for other plants to grow, and their honey is toxic to the European Honeybee. This can have a cascading effect on the entire ecosystem, harming native animal species that depend on the forest for survival, as well as inhibiting our native flora from growing. The conservation of our Celtic Rainforests is essential to protect nature and the myriad of life forms it supports. Unfortunately, invasive species such as Rhododendron ponticum are a major threat to these fragile ecosystems.

If left unchecked, is can have a vastly detrimental effect on the biodiversity and the whole ecosystem within our Celtic Rainforests. It is imperative that we take steps to control these invasive species and restore our rainforests to their natural state. This is where conservation and protection efforts come in - by actively eradicating invasive species such as Rhododendron ponticum and replanting with native species, we can restore our rainforests to a healthier state and protect them for future generations.

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Wouldn't you prefer these types of dappled glades as opposed to the dense dark shadow of Rhododendron ponticum?

What are we doing in the fight to restore our Celtic Rainforests?

The Welsh Celtic Rainforests

The project, worth £7.5 million, aims to improve the conservation status of Wales’ ancient oak woodlands – a very special habitat with a wealth of rare mosses, liverworts and lichens of international importance. Primarily funded through the European Commission’s LIFE Nature and Biodiversity Programme and the Welsh Government, the project aims to tackle many of the threats that this habitat is facing – such as invasive alien species, lack of appropriate grazing, and conifer infestation.

Managing invasive species such as the Rhododendron ponticum

One of the project’s main objectives is to eradicate Rhododendron ponticum from 5 Special Areas of Conservation including Snowdonia, Meirionnydd Oakwoods, Coed Cwm Einion, Coed Cwm Elan and Cwm Doethie – Mynydd Mallaen. It will also be working within a substantial "buffer-zone" around these SACs - in the hope of removing seed sources and future re-infestations. For years the Eryri National Park Authority has been actively managing this pest in parts of Eryri, and our project will continue on the groundwork previously done, be it on a much larger scale!

Conservation grazing

This project will also use hardy breeds of cattle to improve the condition of some of the woodlands – after all, wild animals or livestock have a long history of grazing these woodlands. It’s important to strike the right balance: grazing too heavily and the trees will be damaged and a lack of young saplings: too little and bramble will start to suffocate any other plants. With the right levels grazing it will be possible to sustain the wealth of lower plants and all associated wildlife.

Plantation on Ancient Woodland Sites (PAWS) Restoration

We will also be working on PAWS sites where many tree species commonly seen are not considered native to these particular habitats. This includes all commercial conifer species, in addition to some deciduous trees such as sycamore (Acer pseudoplatanus)and beech (Fagus sylvatica). Careful and gradual restoration management can secure and enhance the remnants of the original ancient woodland, moving it towards a revitalised, more natural state and slowly transforming it back into precious Celtic Rainforest habitat.

Examples of the successful treatment of Invasive Species

One of the UK's most notorious invasive species is Rhododendron ponticum, a beautiful but destructive plant that can quickly take over entire ecosystems, displacing native vegetation and threatening biodiversity. Fortunately, there have been successful attempts to get rid of it. One such case is the project carried out in Killarney National Park in Ireland, where the plant was cut down and its roots removed, together with the use of herbicides and careful monitoring to prevent regrowth. The results were amazing, with the ecosystem recovering and thriving with native plants and wildlife.

Another success in controlling invasive species was the mink eradication program in the Cairngorms National Park. The program became the world's largest mainland species eradication program and involved hundreds of Citizen Scientists volunteering their time. The researchers used data collected by conservation volunteers to predict where mink was likely to recolonize and targeted these areas with ecological traps used to humanely remove the mink from large areas of land. In 3 years, the project had removed 376 mink from 10570 km2, and 186 volunteers took part.

The project helped secure the future of the water vole, and the project is now being used as a template for invasive mink management in other initiatives in Scotland and also around the world.

Finally, there was an interesting experiment by the Canals and Rivers Trust on the treatment of Himalayan Balsam at Penarth Feeder, by first dredging the waterway, placing the silt in a layer on top of a hessian membrane above the Hb, it acts as a weed suppressant! You can see the success of this method on their webpage: https://canalrivertrust.org.uk... -2025 /remove-himalayan-balm-in-new-eco-friendly-trial

These successes show that it is possible to control and remove invasive species, but it requires careful planning, expertise, persistence, and a great deal of patience.

How you can help...

One of the most important ways you can help is through education; of ourselves and others, on the harmful effects of invasive species. Changing the narrative takes time. The more people who are aware of the damage invasive species cause, the more likely they are to take action to stop their spread.

As members of the community, we all have a responsibility to help stop the spread of invasive species. Here are the ways you can get involved:

Be Plant Wise

If you are a gardener or plant in public spaces, be careful about the species you choose. Avoid non-native plants and look for local alternatives that will thrive in the environment without taking over. A diverse native hedge in the springtime is a sight to behold!

Biosecurity

If you work or spend time in a high-risk area, be aware of the steps you can take to avoid the spread of invasive species. This could include washing your equipment, cleaning your shoes, or avoiding certain areas altogether.

Species Alerts

Be aware of the species included on this list - some are Species that are not yet troublesome in Britain but have the potential to cause great harm if given the opportunity to establish. The Asian hornet is currently one of the Species on the watch list.

Species Alerts

Invasive Species Reporting

If you see a potential invasive species in your local area, report it to the relevant authorities as soon as possible. This will allow for prompt action and may help prevent further damage.

Report Invasive Species

Follow us

On social media, share our website and spread the word! Tell your colleagues, friends, and family about the valuable work we do against the invasives threat to our Celtic Rainforests!

By taking these simple steps, we can all help protect our Celtic Rainforests and other natural habitats. So, let us do our part and make a difference today!