Each year, Invasive Species Week raises awareness of one of the most significant threats facing wildlife and natural habitats across the UK.

At ARC, we work to conserve amphibians, reptiles, and the habitats they depend on. From ponds and wetlands to heathlands, grasslands, and coastal environments, healthy ecosystems are essential for the survival of native species. However, these habitats face growing pressures from invasive non-native species, making awareness and action more important than ever.

Invasive Species Week provides an opportunity for everyone to learn how simple actions can help protect the wildlife and landscapes we all value.

 

What Are Invasive Non-Native Species?

Non-native species are plants, animals, fungi, or other organisms that have been introduced to areas outside their natural range (often through trade, travel, gardening, or transport). While many non-native species coexist harmlessly with native wildlife, some become invasive. These species spread rapidly, outcompete native plants and animals, alter habitats, and can cause significant environmental and economic damage (IPBES, 2023).

Examples found in the UK include Japanese knotweed, Himalayan balsam, signal crayfish, grey squirrels, and the Asian hornet. Once established, invasive species can be extremely difficult and costly to control.

 

Various examples of invasive species - report sightings to irecord.org if you see any in the UK. <Photo: Adobe Stock>.

 

Why Are Invasive Species a Problem?

Healthy habitats are the foundation of biodiversity. Native plants provide food and shelter for wildlife including amphibians and reptiles, creating complex ecological networks.

When invasive species take hold, these natural systems can become unbalanced.

Invasive plants may dominate ponds, wetlands, heathlands and grasslands, reducing the diversity of native vegetation. Invasive animals can compete with native species for food and habitat, introduce diseases, or disrupt food chains.

For organisations like ARC, habitat conservation is at the heart of everything we do. Across the UK, we work to restore and manage habitats that support some of our most vulnerable species. Protecting these environments from invasive species is an important part of ensuring they remain suitable for native wildlife both now and in the future.

The Impact on Amphibians and Reptiles

Many of the UK's amphibians and reptiles rely on carefully balanced habitats.

Ponds need healthy aquatic vegetation and good water quality for species such as great crested newts and common frogs. Reptiles such as sand lizards, smooth snakes, and adders depend on diverse heathland, grassland, and coastal habitats that provide shelter, basking areas, and prey.

When invasive species alter these habitats, the effects can ripple throughout the ecosystem. Changes to vegetation structure, water quality, or prey availability can affect the species that ARC works hard to conserve.

Invasive species can also harm native amphibians and reptiles by introducing disease, competing with natives or disrupting local food webs. Releases of non-native amphibians are a particular risk, as they may carry diseases which could be catastrophic for native species. For example, it is thought that a fungal disease introduced via the international amphibian pet trade has resulted in a 99% decline in fire salamanders in the Netherlands (Spitzen-van der Sluijs et al., 2016).

 

Native to North America, the bullfrog has become invasive in parts of the world outside its natural range. Their large size, voracious appetite, and ability to carry diseases make them a concern for native amphibians and other freshwater species  <Photo: Adobe Stock>.

How Are Invasive Species Introduced and Spread?

Many invasive species are introduced accidentally, for example as “hitch-hikers” with traded goods such as plants. They may also be introduced deliberately, for example when people release unwanted plants or pets into the wild. Once here, invasive species may be easily transported by everyday activities such as the movement of garden waste or transported on a wide range of equipment and materials, including boats, kayaks, paddleboards, canoes, fishing gear, walking boots, outdoor clothing, vehicles, machinery, garden waste, and soil.

Even tiny fragments of some invasive plants can establish new populations in different locations. As people who enjoy nature reserves, waterways, coastlines, and the countryside, we all have a role to play in preventing their spread.

Simple Actions That Make a Difference

Check, Clean, Dry

If you use rivers, lakes, ponds, or coastal waters for recreation, always:

Check equipment for mud, plants, or animals.

Clean everything thoroughly before leaving the site.

Dry equipment completely before using it elsewhere.

This simple routine helps prevent invasive species from moving between water bodies and habitats.

 

Be Plant Wise

Gardeners can make a significant contribution by choosing non-invasive plants, disposing of garden waste responsibly, and never releasing pond plants into the wild. Taking the time to learn about species that may pose risks to local habitats can also help protect native wildlife and ecosystems. Many invasive plants originally escaped from gardens before becoming established in the wider countryside.

 

Pet Dumping

One of the most preventable pathways for invasive species introductions is the release of unwanted pets into the wild, often known as "pet dumping".

While releasing an animal may seem like a compassionate option, it can have serious consequences for both the individual animal and native wildlife. Many exotic pets are unable to survive in the British climate and may suffer from starvation, disease, or predation. Others can establish wild populations, compete with native species, alter habitats, or introduce harmful diseases and parasites.

For amphibians and reptiles, pet dumping poses particular risks. Non-native species such as terrapins, exotic frogs, lizards and snakes are occasionally released into local ponds, heathlands and woodlands. Even when these animals do not survive long-term, they may carry pathogens that native wildlife has little or no resistance to.

If you can no longer care for a pet, seek advice from an exotic pet retailer, breeder, or specialist rehoming service rather than releasing it. Responsible pet ownership helps protect both animal welfare and the health of our native ecosystems.

 

Report Sightings

Early detection is one of the most effective tools in invasive species management.

Reporting sightings helps conservation organisations, land managers, and local authorities understand where invasive species are present and where action may be required.

To report sightings of non-native amphibians and reptiles, use a recognised system such as Record Pool.

 

Supporting Nature Recovery

Conservation is about more than protecting individual species. It is about creating healthy, resilient ecosystems where wildlife can flourish.

At ARC, our work focuses on restoring habitats, managing nature reserves, monitoring wildlife populations, and inspiring people to connect with the natural world. These efforts help create landscapes that are better able to support native biodiversity and withstand environmental pressures.

Preventing the spread of invasive species is an important part of this wider picture. By protecting habitats from invasive threats, we can help ensure that amphibians, reptiles, and countless other species continue to thrive.

By making informed choices about the plants we grow and how we manage our gardens, we can all play a part in reducing the spread of invasive species. Small actions can make a real difference for local wildlife and habitats.

 

Pathway Action Plans

It is now widely recognised that attention on non-native species should increasingly focus on preventing their arrival where feasible. One way to guide such efforts is via “Pathway Action Plans”, which aim to disrupt the route via which non-native species are introduced – i.e. their pathway to arrival. ARC has made recommendations to Government on key pathways that apply to non-native species affecting native amphibians and reptiles, including zoos and aquaria, pet trade and horticulture. You can read more on this topic here: https://www.gov.uk/government/consultations/pathway-action-plans-for-invasive-non-native-species-in-great-britain

References 

• IPBES (2023). Thematic Assessment Report on Invasive Alien Species and their Control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Roy, H. E., Pauchard, A., Stoett, P., and Renard Truong, T. (eds.). IPBES secretariat, Bonn, Germany. https://doi.org/10.5281/zenodo.7430682
• Spitzen-van der Sluijs, A., Martel, A., Asselberghs, J., Bales, E. K., Beukema, W., Bletz, M. C., ... & Lötters, S. (2016). Expanding distribution of lethal amphibian fungus Batrachochytrium salamandrivorans in Europe. Emerging infectious diseases, 22(7), 1286.