Invasive species cost the UK £2 million a year to monitor and control. Is this a good use of money? An invasive species is one that has been introduced by humans to an area that it does not live naturally. Starter © Snapshot Science, 2010

Your task: For each animal, award a score out of 5 for each criterion: (0 = no known impact to 5 = maximum possible impact) Criteria: Predation and competition – do they prey on native animals, or compete with them? How many different species are affected? Transmission of diseases – do they carry diseases which can harm other animals? Impact on agriculture – do they damage crops? Distribution – how much of the UK have they invaded? (the dots on the maps show locations of breeding populations) Add up your scores for each animal to give an overall impact score out of 20. Activity © Snapshot Science, 2010

Activity © Snapshot Science, 2010 American MinkRose-ringed parakeet Grey squirrel American bullfrog Images:GBNNSS Feeds, on and competes with, a wide range of prey, including amphibians, fishes, small mammals, ducklings and small bird species, molluscs, crustaceans and insects. This affects populations of native frogs, toads and newts. American bullfrogs may carry the a type of fungus which causes spreads of the disease chytridiomycosis to native amphibians. Significant population declines of ground nesting birds and small mammals have resulted from mink predation. The European mink is threatened by the American mink through competition by means of direct aggression. Little is known about mink as a vector of disease but Aleutian disease has been found in a feral population. Can inflict damage to free ranging chickens, reared game birds, fisheries (salmon farming). In overlap areas, grey squirrel causes the extinction of the red squirrel through competition. Also carries poxvirus, fatal to red squirrels but benign to grey squirrels (and potentially transferrable to humans). Also cause damage to woodland through bark stripping activity. Potential impact on nesting birds. Severe damage to trees by bark stripping. They cause local damage to fruit orchards and nut growers. Rose-ringed Parakeets can compete for nest sites with native cavity nesters. In its native range in India, rose-ringed parakeet is considered one of the most destructive bird pests of agriculture, for example reducing maize yields. In Britain, the species can damage fruit trees and has been reported to have reduced the output of a vineyard. Rose- ringed parakeets can carry diseases that also infect poultry.

© Snapshot Science, 2010 Canada gooseSika deer Harlequin ladybird Chinese mitten crab Images: Chinese mitten crab: Fera, harlequin ladybird: Remy Ware, others: GBNNSS These birds are heavy grazers of aquatic and waterside vegetation, which is food for many other animals. There is concern that the presence of so many large birds in close association with people, for example in urban parks, may be a health hazard. Canada geese are suspected of transmitting salmonella to cattle. Their grazing and trampling on farmland may cause major damage to grassland and crops. Likely to impact native invertebrate populations in freshwater and marine systems, through predation and competition for space. Has the potential to outcompete the native white-clawed crayfish. The Chinese mitten crab carries a number of diseases that can affect native fish. These crabs may cause loss of salmon and trout in commercial fisheries because of predation or competition. Harlequin ladybirds are larger than native ladybirds and devour their larvae. They also eat aphids, leaving less food for them. During winter they gather in buildings and can cause people allergic reactions. Harlequin ladybirds are a pest of apple and pear orchards. They feed on fruit causing blemishing and an associated reduction in market value. Harlequins aggregate in clusters of grapes prior to harvest and when crushed with the grapes the ladybirds impart a disgusting flavour to the juice. Damage is due to ring barking, trampling, erosion due to creation of trails and reduction of water quality in streams. In Eastern Europe, sika play a role in the transmission of a nematode affecting bison, roe deer, red deer and potentially livestock. Both bovine and avian TB has been found in sika deer. Sika are a serious forest pest, causing significant damage to tree plantations. Activity