Mark Iley Biodiversity Coordinator 01621 862975 marki@essexwt. org. uk www. essexbiodiversity. org. uk
Killer shrimp!
Only 10% thought that ‘plants, animals and insects not normally found in the UK’ had an effect on biodiversity. (only 50% of those questioned had heard of or understood the term biodiversity) 2009 DEFRA report on ‘Public attitudes and behaviour towards the environment’
What are invasive non-native species? • There are 2, 721 non-native species living in England of which the majority (1, 798 or 66%) are plants. • Most non-native species do not cause problems. Only a minority have become invasive and have negative impactson agriculture, forestry or biodiversity interests. • Invasive non-native species are the second biggest threat to biodiversity worldwide. Globally, invasive species cost an estimated £ 914 billion pa and are the cause of half all extinctions. Considered even more damaging than pollution or climate change.
What are invasive non-native species? • Invasive non-native species come from all over the world, some from continental Europe (e. g. Zebra Mussels) some from Asia (e. g. Chinese Mitten Crab), some from America (Grey Squirrel, Mink, Ruddy Duck, Ludwigia, Signal Crayfish), some from Africa (Hottentot Fig) and some from Australia (Australian flatworm) and New Zealand (NZ Pigmyweed, NZ flatworm). • intentional (e. g. deliberate release of non-native species like ) and some • unintentional (e. g. by ‘hitch-hiking’ on food or other goods imported into Britain or by escaping from captivity (e. g. American mink)). • Some marine species are transported large distances on ships or in ships ballast water (e. g. Chinese mitten crabs). • Many plant species are brought in intentionally as part of the horticulture trade but some then become established in the wild after that are disposed of irresponsibly or ‘escape’.
Are they increasing and spreading? • Yes, the number of non native species becoming established in the UK is likely to increase due to the growth in world trade and global tourism. • Climate change may also allow species that are currently benign in Britain to become invasive. • The risks associated with invasive non-native species are therefore likely to remain a feature of our lives.
Should I care - how do they affect me? • They are expensive! Recent estimates suggest that their total cost is about £ 2 billion pa (Pimentel, 2002). Increased flooding risk and damage to infrastructure, bridges, water treatment facilities, impact on fisheries etc. The cost of control of invasive water weeds alone is over £ 3 million pa • The biodiversity impacts of invasive non-native species are severe and growing, challenging the survival of our rarest species – for Red squirrel, Water vole, White clawed crayfish etc and damaging some of our most sensitive ecosystems, particularly freshwater • Some species have a direct impact on our health (eg Giant Hogweed, oak processionary moth, terrapins (which can carry Salmonella) • Unlike some other serious environmental problems, such as pollution, the effect of an invasive non-native species is not a one off event. Once a species has been introduced the problems persist and escalate as the species spreads. • If we don't act, the problem of invasive non-native species will continue to escalate at an ever increasing rate, causing us to feel more of the impacts and incur more cost every year.
Are all non-native species going to be eradicated? • No, The UK non-native species framework strategy is concerned primarily with prevention • The UK strategy is concerned with addressing only those non-native species that are thought to present a significant risk of being invasive. • It is recognised that eradication is usually only practically feasible and financially affordable in the early stages of an invasion. • Once invasive species are well established, it is usually a case of mitigation measures and localised or possibly regular removal.
Japanese Knotweed • Japanese knotweed is one of the most notorious invasive alien species in Britain today. Native to Japan, Taiwan and Northern China, it was introduced to Britain in the 19 th century as an ornamental plant. • It spreads solely by vegetative means (it does not produce viable seeds) and a new plant can grow from a tiny fragment of root or stem. • The plant has negative impacts on biodiversity through the smothering of native vegetation. • DO NOT FLAIL MOW this plant. Do not use mechanical control as this is likely to spread and increase infestation unless coupled with chemical control of the residues or burning on site. . Digging, ploughing and dredging are unlikely to have any long-term benefit because of the extensive nature of the rhizome system and because of the ability of even small fragments to regrow. • • • The only herbicide approved for use in or near water which controls this plant is glyphosate. Spray in August - October during the flowering period. Control is usually improved if the herbicide is applied to both sides of the leaves. • Herbicides containing picloram (Tordon 22 K), imazapyr (Arsenal) and triclopyr (Garlon 4) are more effective away from the water’s edge.
Giant Hogweed • Giant hogweed was first introduced to the UK in 1893 as an ornamental plant. Each plant can grow up to 5 m in height and produce up to 50, 000 seeds. It forms dense colonies which shade out native vegetation. • This species also poses a threat to public health. A toxic chemical in the sap sensitizes the skin which can lead to severe blistering when exposed to sunlight. THIS REACTION CAN RECUR FOR MANY YEARS. • Hand cutting should never be undertaken unless the operator is wearing full protective clothing to prevent skin contamination by the sap. Machine operators should take similar precautions because the sap can be spread onto machinery and subsequently come into contact with skin • The only herbicide which is known to control Giant Hogweed and which is approved for use in or near water, is glyphosate. • Spray individual plants or whole colonies with glyphosate in April or May. Spot treat new plants as they appear.
Himalayan Balsam • Himalayan balsam was introduced to the UK in 1839 as an ornamental plant at Kew gardens and was first recorded in the wild in 1855. It forms dense stands of vegetation 2 -3 m in height that shade out native plant species. • Himalayan balsam is also a prolific nectar producer, meaning that bees will preferentially visit these plants. This reduces seed production in native plant species and biodiversity as a whole. • The plant is easy to cut, either by hand or machine, provided there is adequate access. Unless the plant is cut below the lowest node, it will regrow and flower later in the season. Thus, a single cut is only effective if made very close to the soil level. Small infestations can be controlled by hand pulling as the plant is shallow rooted. • The seedbank lasts for approximately 18 months, so two years control should eradicate the plant if there is no further infestation from upstream • Control existing infestations of Himalayan Balsam by spraying with glyphosate, 2, 4 -D amine or by regular cutting. Carry out regular inspections of the banks in spring and hand pull or spot treat any germinating seedlings with a weed wiper or knapsack sprayer.
Floating Pennywort • Floating pennywort is native to North America. After being introduced as an aquatic garden plant in the Eighties, this 'water triffid' soon went wild The species was first found in the wild in Britain in 1990 at a site in Essex. • It grows in huge, dense mattresses that choke waterways, starving the water of light, oxygen and nutrients. Under UK conditions mats of vegetation have been observed to grow up to 15 metres from the bank in a single season, growing at approximately 20 cm per day! • The plant reproduces principally by asexual, vegetative means and a new plant can grow from a single node • For effective long-term control Reglone should be employed. Follow up any treatment programme with an inspection after a period of one month incorporating spot treatments of herbicide or physical removal where necessary. • When mechanical cutting the affected areas should be fenced off to prevent the downstream spread of the plant. All cut foliage should be removed from the water body. • Physical control methods are likely to have limited effect other than a short-term reduction in the local extent of the plant. Remove this plant as soon as it is observed.
Australian/NZ Swamp Stonecrop ‘Crassula’ • Also known as New Zealand Pygmy Weed, this aquatic plant was introduced to Britain from Tasmania in 1911 and was first recorded in the wild in 1956. Crassula is an extremely invasive species which is not easy to control. • It forms dense mats on water bodies that shade out other aquatic vegetation, consequently having a negative impact upon fish and invertebrate communities. • Crassula can also increase the risk of flooding and restrict amenity activities, such as fishing. • DO NOT PRACTICE MECHANICAL CONTROL ON THIS PLANT. The fragments that are produced by cutting and tearing can regrow and spread the infestation downstream or re-infest the treated area. Fragments as small as 5 mm can regrow. • Crassula is only really susceptible to herbicide formulations containing glyphosate. (Diquat has been withdrawn from aquatic use by the EU, but the products are the subject of appeals to reinstate their use on this species). • It is recommended that at least 70% of dense infestations is treated at one time to reduce recolonisation from untreated areas. Treatment of the remaining 30% should be carried out after 1 week. The dead material should be removed two to three weeks after treatment if possible, but can remain in the waterbody if necessary.
Parrots Feather • Parrot's feather is native to Central and South America and has been grown in water gardens in the UK since 1878. First found in the wild in 1960, it does not spread by seed (as all the plants in the UK are female) but is able to re-grow from small fragments of parent plants. • Parrot's feather can cause flooding by blocking watercourses and drainage channels. It also out-competes native species, reducing overall biodiversity. • Mechanical control is effective for removing large infestations of this plant in areas where access is available for weed cutting buckets or boats. Care should be taken to restrict the downstream movement of stem fragments which will result from cutting operations as regrowth is rapid from this type of propagule. The stems of this species are especially brittle and fragmentation occurs readily when the plant is cut. • The plant is controlled by applications of dichlobenil in April. It is also controlled by herbicides containing 2, 4 -D amine as the active ingredient in early April. It is also controlled by applications of glyphosate late in the season, and also to some extent by applications from April onwards. • Chemical control will lead to a short-term eradication of this species, as recolonisation from original sources will often occur. It is important to establish where the infestation has come from and take action to eliminate the source of material.
American Mink • The American Mink (Mustela vison) was brought to Great Britain in the early 20 th century for fur farming, but became established in the wild after escapes and deliberate releases. By the middle of the 20 th century mink had become widespread. • Among their prey is the native and protected Water Vole (Arvicola terrestris). Since the introduction of mink, Water Voles have rapidly declined by as much as 94% and are 'one of the most rapid and serious declines of any British wild mammal during the 20 th century' • They are opportunistic predators and will take a wide variety of prey, in addition to water voles, including water bird eggs and nestlings • At the moment lethal trapping is the only feasible method for containing or eradicating mink. Traps can be placed along the riverbank or on floating rafts. In most areas live-traps are recommended to avoid non-target impacts. Exclusion devices for otters should be used when appropriate. • Essex Wildlife Trust – Water for Wildlife Officer coordinating mink trapping
American Signal Crayfish • Native to North America, signals carry a disease, crayfish plague, that is deadly to our threatened native white-claw crayfish. Introduced for food in the late 1970 s and 1980 s but spread quickly across much of the UK. • Distinguishing nonnative species from the threatened native whiteclawed crayfish is essential. Compared to the native species, the signal crayfish is much larger and its claws are red underneath with a small turquoise / white blotch on the surface. • Spreads up and downstream and may cross land to colonise adjacent water bodies. Human transfer, although illegal, still continues. • Negative impacts include the almost complete loss of the native crayfish through the spread of disease and direct competition. Also undermines riverbanks through burrowing and predates on native fish eggs and aquatic invertebrates. • License required form EA to trap
Chinese Mitten Crab This Asian species has made its home in some UK fresh waters, including the Thames. It damages riverbanks by burrowing into them, and out-competes native species. • It is no longer possible to prevent the arrival of Chinese mitten crabs into Great Britain and now it has arrived, it can be expected to spread through natural dispersal. However, intervention may be possible to prevent new populations becoming established in uninfested rivers. • No methods of mechanical management are known, although in some parts of the world, the species is caught using traps. Should a commercial fishery be developed for this species, care would need to be taken that crabs are not introduced deliberately into new river systems to develop new fisheries as has been the case with the signal crayfish.
Topmouth Gudgeon • Introduced to the wild in Britain in the 1960 s from their native Asia • They breed at four-times the rate of native fish and carry a parasite, similar to, or possibly the same as, a disease called "rosette agent" which is found in some US fish stocks - known to be deadly to salmon and trout. • Topmouth gudgeon also eat vast quantities of plant life, invertebrates and fish eggs which upsets the natural balance of a pond, lake or river. As a result, algal blooms can occur turning the water into a green soup. Topmouth gudgeon are extremely difficult to get rid of. Rotanone (fish pesticide) can be used to kill all fish in ponds but is not usable in larger waterbodies or rivers • Topmouth fry, which can be the size of an eyelash, can be hidden away in the mouths and gills of other fish and get accidentally transferred to other waters. • Topmouth gudgeon is listed as a category 5 risk species under the Importation of Live Fish Act (ILFA) which is the highest level of risk. It is an offence to introduce any fish or eggs of fish into the wild without the prior written consent of the Environment Agency.
American bullfrog • The American bullfrog eats almost any other species, and carries a disease that has wiped out many other frog and toad populations. It breeds rapidly, with each female laying up to 30, 000 eggs at a time. • It is very important to prevent further releases into the wild. Education programmes are needed to reduce the rate of introduction. • Control of American bullfrogs in Britain has led successfully to local eradication. Methods employed are egg collection, tadpole trapping and the shooting of juvenile and adult animals.
Can we really do anything about non-native species? • Government can ensure that there adequate inspections on imports to detect invasive species and can support research and management of invasive species where appropriate. • The GB Non-native Species Strategy sets out the measures the to raise awareness and understanding of the risks, to gather information and to minimise the risks of further introductions or establishment of invasive species. • Surveillance and monitoring of non-native species is key • Organisations covering a wide range of interests from business to hobbies can help inform their members about these issues and everyone can adopt more responsible attitudes and behaviours • Everyone can be alert and report – early action can be critical
Can we really do anything about non-native species? Eat them…? Venison, crayfish, squirrel…
Key actions • Be alert - learn to recognise the commonplace and notice anything unusual • Report any non native invasive species – note location accurately and get a sample/specimen • Get information on ecology and management via GB Non-native Species Secretariat (NNSS) www. nonnativespecies. org Environment Agency http: //www. environmentagency. gov. uk/homeandleisure/wildlife/31350. aspx
Key actions • Dispose of your waste in a responsible way (do not fly tip!). Compost unwanted plants – Japanese Knotweed is classed as ‘controlled waste’ and as such must be disposed of safely at a licensed landfill site • Always buy native aquatic plants from reputable suppliers. • Beware of hitch-hikers! Don't swap pond plants or animals (including frog spawn) between ponds. This might sound overly cautious, but it only takes a tiny fragment of many invasive aquatic plants for a new plant to grow. • Do not release unwanted pets or fish into the 'wild' • Anglers can play a key role. Crayfish plague can be spread on angler's equipment if it is not properly dried out after fishing an infected area. • Spread the word! Tell your colleagues and friends about invasive non-native species and the impacts that they are having.
Basic Biosecurity • Biosecurity means taking steps to make sure that good hygiene practices are in place to reduce and minimise the risk of spreading animal and plant species and diseases. • A good biosecurity routine is always essential, even if problems are not apparent • Biosecurity should be considered at the earliest stage when planning any field work, from surveying an area to removing non-native species. • Biosecurity measures can be as simple and as quick as making sure footwear is clean. • Plan visits so that the most risky visit is the last one of the day
Whats next…!
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