Invasive Non-native Species

With guidance from Sussex’s leading naturalists, Sussex Biodiversity Record Centre have compiled a list of 49 invasive alien species which occur in Sussex.

American Mink

Photo: Hugh Clark/Sussex Wildlife Trust

More information about the Sussex Invasive Alien Species Report

What do the Brown Hare, Red-legged Partridge and Horse Chestnut have in common? None of them are native to the UK. They were in fact introduced here by people hundreds of years ago and have since gone on to naturalise – they have formed populations that can survive and reproduce in the wild without human help.

There are 2271 non-native species found in England. Many of these were deliberately introduced for purposes such as agriculture and forestry, and have contributed to our social and economic well-being. There are however, a small number of invasive non-native species which are extremely damaging to our natural environment, and can create huge economic costs.

So what’s the problem?

Invasive non-native plant and animal species are the second greatest threat to biodiversity worldwide (after habitat destruction). They can negatively impact on native species, can transform habitats and threaten whole ecosystems causing serious problems to the environment and the economy GB Non-native Species Secretariat

  • Non-native species didn’t evolve here. This means they have none of the usual predators, parasites and pathogens that keep populations of our native species in check, which can give them a distinct advantage.
  • Invasive non-native plants often form a dense monoculture, which removes habitats for other plants and animals, and can also reduce food supplies.
  • Invasive non-native animals can severely impact our native species through competition or by feeding on them. Our native species can be vulnerable as they have not evolved strategies to outwit these new predators.
  • Invasive non-native plants are often fast growing and adaptable so can take advantage of many situations. This could further increase with climate change.
  • Non-native species sometimes reproduce with native species producing a hybrid. These hybrids are sometimes infertile, but those that are not can begin to alter the genetic pool, endangering native species.

Giant Hogweed

Photo: Tony Buckwell/Sussex Wildlife Trust

What can be done?

  • Know your non-natives! Current species alerts include Carpet Sea-squirt, Water Primrose, Killer Shrimp and Asian Hornet.
  • Report invasive non-native species through Sussex Biodiversity Record Centre. Plants such as Giant Hogweed and Japanese Knotweed on public land should also be reported to your local council.
  • Many non-natives escape from gardens or ponds. To prevent this, use native species local to your area. Flora locale provide information on finding native plant species.
  • Never release any plants or animals in to the wild – it is against the law Your local council can advise you on how to dispose of garden waste correctly.

Harlequin Ladybird

Photo: Graeme Lyons/Sussex Wildlife Trust

More information about invasive non-native species

GB Non-native Species Secretariat