Non-Native species: A-Z

Here’s an alphabetical list of non‑native species established (resident) in the British Isles, grouped by major taxonomic categories and including scientific names.

This list focuses on species known to have self‑sustaining wild populations rather than species that have been seen only sporadically or in captivity.

This is not a full list of all non-native species. Authorities such as the GB Non‑Native Species Secretariat (NNSS) list over 2,000 non‑native species established in Great Britain, including animals, plants and other organisms.

Non-Native Species Secretariat

A — Birds, Animals & Plants

African sacred ibis — Threskiornis aethiopicus (wild populations recorded)

Alligator weed — Alternanthera philoxeroides (invasive aquatic plant)

American bullfrog (pictured) — Lithobates catesbeianus (established populations; invasive threat)

American skunk cabbage — Lysichiton americanus (listed invasive plant)

Asian hornet (yellow‑legged hornet) — Vespa velutina nigrithorax (spreading non‑native wasp)

C — Crustaceans, Mammals & Plants

Chinese mitten crab — Eriocheir sinensis (widely spread invasive crab)

Coati — Nasua nasua (non‑native mammal occasionally established)

Cotoneasters (various species) — Cotoneaster spp. (naturalised shrubs, some invasive)

E — Birds & Shrubs

Egyptian goose — Alopochen aegyptiacus (naturalised waterfowl)

F — Aquatic & Terrestrial Plants

Floating pennywort — Hydrocotyle ranunculoides (invasive aquatic plant)

G — Plants, Mammals & Fungi

Giant hogweed — Heracleum mantegazzianum (widely invasive plant)

Grey squirrel — Sciurus carolinensis (abundant non‑native mammal)

Gunnera (Chilean rhubarb) — Gunnera tinctoria (listed invasive plant)

H — Plants & Other Organisms

Himalayan balsam — Impatiens glandulifera (highly common invasive plant)

I — Plants

Indigo bush (Amorpha fruticosa) and similar ornamental shrubs — naturalised in some areas (not on formal lists but present widely).

M — Fishes, Insects & Mammals

Marbled crayfish — Procambarus virginalis (parthenogenetic crayfish)

Muntjac deer — Muntiacus reevesi (established deer species)

N — Plants & Amphibians

Nuttall’s waterweed — Elodea nuttallii (invading aquatic plant)

O — Birds, Fishes & Reptiles

Orange‑bellied slider and other terrapins (e.g., red‑eared slider) — Trachemys scripta (established releases in waterways)

Orfe — Leuciscus idus (introduced fish species present in some waters) (commonly listed in introduced fish records)

P — Fish & Worms

Percottus (Chinese sleeper / Amur sleeper) — Percottus glenii (non‑native fish)

Pumpkinseed — Lepomis gibbosus (introduced fish)

R — Birds, Rodents & Crustaceans

Raccoon — Procyon lotor (non‑native mammal species)

Raccoon dog — Nyctereutes procyonoides (listed invasive mammal)

Red swamp crayfish — Procambarus clarkii (invasive freshwater crayfish)

Ruddy duck — Oxyura jamaicensis (formerly widespread waterbird; now largely controlled)

S — Crayfish, Crustaceans & Other Vertebrates

Signal crayfish — Pacifastacus leniusculus (substantial invasive freshwater crayfish)

Spiny‑cheek crayfish — Orconectes limosus (Faxonius limosus) (invasive crayfish)

Striped eel catfish — Plotosus lineatus (tropical fish recorded in UK waters)

T — Fish, Mammals & Reptiles

Topmouth gudgeon (stone moroko) — Pseudorasbora parva (invasive fish species)

V — Insects

Non‑native flatworms and planarians (e.g., Arthurdendyus, Obama, Australoplana spp.) — landscape‑impacting invertebrate invaders (widely recorded)

Plants & Horticultural Escapes (Additional Examples)

Many non‑native garden plants have naturalised across the British Isles. These are common in the wild but not all are formally legislated “invasive species”:

Balloon vine — Cardiospermum grandiflorum

Broad‑leaved bamboo — Sasa palmata

Japanese knotweed — Reynoutria japonica (seriously invasive)

Pirri‑pirri bur — Acaena novae‑zelandiae

Rhododendron (invasive horticultural hybrids) — Rhododendron spp.

Spanish bluebell & hybrid — Hyacinthoides hispanica and hybrids

Winter heliotrope — Petasites fragrans (naturalised flowering plant)

Notes on Interpretation

According to official biodiversity records:

• Over 3,000 non‑native species have been reported in Great Britain.

• Around 2,000 of these are classified as established.

Non‑native species are those introduced by human action to areas outside their historical range.

Only a subset are classed as 'invasive' in terms of causing ecological or economic harm, though many naturalised species persist without major negative impact.

Legally listed invasive species in England and Wales include both “widely spread” and “non‑widely spread” taxa (animals and plants), such as grey squirrel, Asian hornet, curly waterweed and many more.

Numerous other naturalised species occur that aren’t on legal schedules but are recorded as established (e.g., ornamental garden escapes).

Further Resources

For a far more extensive inventory, the GB Non‑Native Species Information Portal provides searchable data on over 3,000 non‑native species present in Great Britain, including detailed records on origin, introduction pathway and distribution.

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