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Risk assessment

Last edited: Mar 31, 2022, 5:10 PM

Risk assessment is used to assess the risk of a non-native species entering, establishing, spreading and causing impacts in GB. These pages provide information on GB risk assessment scheme developed and used in GB. Completed risk assessments are also posted here. 

Jump to a list of risk assessments

About risk assessment 

Risk assessment is a key tool in the armoury against invasive non-native species.  It can be used to aid prioritisation, to help enable effective rapid responses and for underpinning decision-making.  The Non-native Risk Assessment (NNRA) scheme was established in December 2006 (Baker et al 2008 (external link)Mumford et al 2010 (PDF)).  Within this scheme risk assessments on non-native species are carried out by independent experts, which are then reviewed by one peer reviewer and GB's independent panel of risk analysis experts (known as the NNRAP).  Following this process risk assessments are available for comment before being finalised.

Common misconceptions about risk assessments:

To address a number of common misconceptions about non-native species risk assessments, the following points should be noted:

  • Risk assessments consider only the risks posed by a species. They do not consider the practicalities, impacts or other issues relating to the management of the species. They therefore cannot on their own be used to determine what, if any, management response should be undertaken.
  • Risk assessments are advisory and therefore are part of the suite of information on which policy decisions are based.
  • Completed risk assessments are not final and absolute. They are an assessment based on the evidence available at that time. Substantive new scientific evidence may prompt a re-evaluation of the risks and/or a change of policy.

Information for those undertaking risk assessments:

Period for comment

The risk assessments that have completed the process are available from these pages.  They are open for stakeholders to provide comment on the scientific evidence which underpins them for three months from the date of posting on this website (to send in your comments contact us). 

If you require an accessible version of a risk assessment please contact us with the following:

  • the risk assessment required 
  • your name and email address
  • the format you need, for example, audio CD, braille, BSL or large print, accessible PDF

We’ll consider your request and get back to you in 15 working days.

If you would like to be informed when new risk assessments are put online, contact us and ask to be put onto the risk assessment alert e-list.

Risk assessments

Common name Scientific name Document type Type Status
A marine copepod Acartia tonsa PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
A nemertean worm Cephalothrix simula PDF Risk Assessment Complete Open
African clawed toad Xenopus laevis PDF Risk Assessment Complete Open
Alpine newt Icthyosaura alpestris PDF Risk Assessment Complete Open
American bullfrog Rana catesbeiana PDF Risk Assessment Complete Open
American lobster Homarus americanus PDF Risk Assessment Complete Open
American skunk cabbage Lysichiton americanus PDF Risk Assessment Complete Open
Andean watermilfoil Myriophyllum quitense PDF Rapid Risk Assessment Complete Open
Argentine ant Linepithema humile PDF Rapid risk assessment Complete Open
Asian clam Corbicula fluminea PDF Rapid Risk Assessment Complete Open
Asian date mussel Arcuatula senhousia PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Asian hornet Vespa velutina PDF Risk Assessment Complete Open
Asian shore crab Hemigrapsus sanguineus PDF Rapid Risk Assessment Complete Open
Atlantic oyster drill Urosalpinx cinerea PDF Rapid Risk Assessment Complete Open
Australian blackwood Acacia melanoxylon PDF Risk Assessment Complete Open
Australian swamp stonecrop Crassula helmsii PDF Risk Assessment Complete Open
Bar-headed goose Anser indicus PDF Rapid Risk Assessment Complete Open
Black bullhead Ameiurus melas PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Black swan Cygnus atratus PDF Rapid Risk Assessment Complete Open
Black tailed prairie dog Cynomys ludovicianus PDF Rapid Risk Assessment Complete Open
Blackcrowned night heron Nycticorax nycticorax PDF Rapid Risk Assessment Complete Open
Brazilian giant rhubarb Gunnera manicata PDF Rapid Risk Assessment Complete Open
Bumblebee Bombus terrestris sp PDF Risk Assessment Complete (updated 2013) Open
Bumblebee Bombus terrestris sp PDF Risk Assessment Original draft Open
Butterfly bush Buddleja davidii PDF Rapid Risk Assessment Complete Open
Canada goose Branta canadensis PDF Risk Assessment Complete Open
Canadian pondweed Elodea canadensis PDF Risk Assessment Complete Open
Cape pondweed Aponogeton distachyos PDF Rapid Risk Assessment Complete Open
Carolina fanwort Cabomba caroliniana PDF Rapid Risk Assessment Complete Open
Carpet sea-squirt Didemnum vexillum PDF Risk Assessment Complete Open
Chinese mitten-crab Eriocheir sinensis PDF Risk Assessment Complete Open
Chinese mystery snail Cipangopaludina chinensis PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Chinese Water Deer Hydropotes inermis PDF Risk Assessment Complete Open
Cider gum Eucalyptus gunnii PDF Risk Assessment Complete Open
Coati Nasua nasua PDF Risk Assessment Complete Open
Common wall lizard Podarcis muralis PDF Risk Assessment Complete Open
Cork ant Crematogaster scutellaris PDF Rapid Risk Assessment Complete Open
Creeping water primrose Ludwigia peploides PDF Risk Assessment Complete Open
Curly waterweed Lagarosiphon major PDF Risk Assessment Complete Open
Demon shrimp Dikerogammarus haemobaphes PDF Rapid Risk Assessment Complete Open
Doctor fish Garra rufa PDF Rapid Risk Assessment Complete Open
Dungeness crab Metacarcinus magister PDF Rapid Risk Assessment Complete Open
Eagle owl Bubo bubo PDF Risk Assessment Complete Open
Eagle owl Bubo bubo PDF Risk Assessment Original draft Open
Edible dormouse Glis glis PDF Risk Assessment Complete Open
Egyptian goose Alopochen aegyptiacus PDF Risk Assessment Complete Open
False acacia Robinia pseudoacacia PDF Rapid Risk Assessment Complete Open
Floating pennywort Hydrocotyle ranunculoides PDF Risk Assessment Complete Open
Garden dormouse Eliomys quercinus PDF Risk Assessment Complete Open
Giant cane Arundo donax PDF Risk Assessment Complete Open
Giant knotweed Fallopia sachalinensis PDF Risk Assessment Complete Open
Giant resin bee Megachile sculpturalis PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Giant rhubarb Gunnera tinctoria PDF Rapid Risk Assessment Complete Open
Giant salvinia Salvinia molesta PDF Rapid Risk Assessment Complete Open
Golden club Orontium aquaticum PDF Risk Assessment Complete Open
Gulf wedge clam Rangia cuneata PDF Rapid Risk Assessment Complete Open
Himalayan knotweed Persicaria wallichii PDF Rapid Risk Assessment Complete Open
Indian house-crow Corvus splendens PDF Risk Assessment Complete Open
Invasive garden ant Lasius neglectus PDF Rapid Risk Assessment Complete Open
Italian crested newt Triturus carnifex PDF Risk Assessment Complete Open
Japanese knotweed Fallopia japonica PDF Risk Assessment Complete Open
Japanese skeleton shrimp Caprella mutica PDF Risk Assessment Complete Open
Killer shrimp Dikerogammarus villosus PDF Rapid Risk Assessment Complete Open
Large flowered waterweed Egeria densa PDF Risk Assessment Complete Open
Manilla clam Ruditapes philippinarum PDF Risk Assessment Complete Open
Marbled crayfish Procambarus sp PDF Risk Assessment Complete Open
Marbled newt Triturus marmoratus PDF Rapid risk assessment Complete Open
Marsh frog Pelophylax ridibundus PDF Risk Assessment Complete Open
Monarch butterfly Danaus plexippus PDF Rapid Risk Assessment Complete Open
Monk parakeet Myiopsitta monachus PDF Risk Assessment Complete Open
Monkey flower Mimulus guttatus PDF Rapid Risk Assessment Complete Open
Muntiacus reevsii Muntjac deer PDF Risk Assessment Complete Open
New guinea flatworm Platydemus manokwari PDF Rapid Risk Assessment Complete Open
New Zealand mudsnail Potamopyrgus antipodarum PDF Risk Assessment Complete Open
Noble crayfish Astacus astacus PDF Risk Assessment Complete Open
Northern river amphipod Crangonyx pseudogracilis PDF Risk Assessment Complete Open
Nuttall’s waterweed Elodea nuttallii PDF Risk Assessment Complete Open
Orange balsam Impatiens capensis PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Pacific oyster Crassostrea gigas PDF Risk Assessment Complete Open
Pacific oyster Crassostrea gigas PDF Risk Assessment Original draft Open
Pampas grass Cortaderia selloana PDF Rapid Risk Assessment Complete Open
Paper wasp Polistes nimpha PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Parrots feather Myriophyllum aquaticum PDF Risk Assessment Complete Open
Pink salmon Oncorhynchus gorbuscha PDF Risk Assessment Complete Open
Pirri-pirri burr Acaena novae-zealandia PDF Rapid Risk Assessment Complete Open
Ponto-caspian goby Babka gymnotrachelus PDF Rapid Risk Assessment Complete Open
Ponto-caspian goby Proterorhinus marmoratus PDF Rapid Risk Assessment Complete Open
Ponto-caspian goby Neogobius melanostomus PDF Rapid Risk Assessment Complete Open
Pumpkinseed Lepomis gibbosus PDF Rapid Risk Assessment Complete Open
Purple pitcher plant Sarracenia purpurea PDF Risk Assessment Complete Open
Quagga mussel Dreissena rostriformis bugensis PDF Risk Assessment Complete Open
Raccoon Procyon lotor PDF Risk Assessment Complete Open
Raccoon dog Nyctereutes procyonoides PDF Rapid Risk Assessment Complete Open
Ragweed Ambrosia artimisiifolia PDF Risk Assessment Complete Open
Rapa whelk Rapana venosa PDF Risk Assessment Comment period over Open
Red king crab Paralithodes camtschaticus PDF Risk Assessment Complete Open
Red-eared terrapin Trachemys scripta elegans PDF Risk Assessment Complete Open
Red-swamp crayfish Procambarus clarkii PDF Risk Assessment Complete Open
Rhododendron Rhododendron ponticum PDF Risk Assessment Complete Open
Ring-necked parakeet Psittacula krameri PDF Risk Assessment Complete Open
Ruddy duck Oxyura jamaicensis PDF EU Risk Assessment Complete Open
Ruddy shelduck Tadorna ferruginea PDF Rapid Risk Assessment Complete Open
Rusty crayfish Orconectes rusticus PDF Risk Assessment Complete Open
Sacred ibis Threskiornis aethiopicus PDF Risk Assessment Complete Open
Sea walnut Mnemiopsis leidyi PDF Rapid Risk Assessment Complete Open
Shining gum Eucalyptus nitens PDF Risk Assessment Complete Open
Siberian chipmunk Tamias sibiricus PDF Risk Assessment Complete Open
Signal crayfish Pacifastacus leniusculus PDF Risk Assessment Complete Open
Sika deer Cervus nippon PDF Risk Assessment Complete Open
Slipper limpet Crepidula fornicata PDF Risk Assessment Complete Open
Spiny-cheek crayfish Orconectes limosus PDF Risk Assessment Complete Open
Striped barnacle Amphibalanus amphitrite PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Striped skunk Mephitis mephitis PDF Risk Assessment Complete Open
Three-cornered leek Allium triquetum PDF Risk Assessment Complete Open
Tingiringi gum Eucalyptus glaucescens PDF Risk Assessment Open
Topmouth gudgeon Pseudorasbora parva PDF Risk Assessment Complete Open
Tree of heaven Ailanthus altissima PDF Rapid Risk Assessment Complete Open
Turkish crayfish Astacus leptodactylus PDF Risk Assessment Complete Open
Virile crayfish Orconectes virilis PDF Risk Assessment Complete Open
Wakame Undaria pinnatifida PDF Rapid Risk Assessment Complete Open
Water fern Azolla filliculoides PDF Risk Assessment Complete Open
Water hyacinth Eichhornia crassipes PDF Risk Assessment Complete Open
Water lettuce Pistia stratiotes PDF Rapid Risk Assessment Complete Open
Water primrose Ludwigia grandiflora PDF Risk Assessment Complete Open
Wels catfish Silurus glanis PDF Rapid Risk Assessment available for comment until 27 May 2022 Open
Western green lizard Lacerta bilineata PDF Risk Assessment Complete Open
White river crayfish Procambarus acutus PDF Risk Assessment Complete Open
Wireweed Sargassum muticum PDF Risk Assessment Complete Open
Worm wart weed Gracilaria vermiculophylla PDF Rapid Risk Assessment Complete Open
Zander Sander lucioperca PDF Rapid Risk Assessment Complete Open
Zander Sander lucioperca PDF Rapid Risk Assessment Original draft Open
Zebra mussel Dreissena polymorpha PDF Risk Assessment Complete Open

Contact us to submit your comments on the risk assessments.

Other Risk Assessment Schemes

The European and Meditteranean Plant Protection Organisation (EPPO) carries out pest risk analysis at the European and Mediterranean scale. Find risk analysis for plant pests (external link) and risk analysis for invasive plants (external link).

The Aquatic Species Invasiveness Screening Kit (AS-ISK (external link) has been developed by Cefas and colleagues to support the identification and management of invasive non-native aquatic species (Copp et al. 2016 (external link)) and has been applied to a wide range of taxa (Vilizzi et al. 2019 (external link)).