Invasive non-native species - Environmental Audit Committee Contents

1  Invasive species threats


1. Invasive non-native (or alien) species exhibit greater abundance, density, or competitive dominance than species that are native to an area, and so adversely affect an existing ecology or habitat. They can also have detrimental effects on human health and well-being and on economically important activities. The rate of introduction of such species has accelerated with the expansion of international trade and travel. A study in 2012 counted 1,875 non-native species established in Great Britain—a figure increasing by 10 species a year—of which 282 had become invasive.[1] At the global level, invasive species were ranked as one of most important drivers of biodiversity loss by the Millennium Ecosystem Assessment in 2005.[2]

2. The UK has existing international obligations to address the effects of invasive species. The UN Convention on Biological Diversity requires member states: "as far as possible and as appropriate, [to] prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species".[3] One of the Convention's Strategic Plan targets, adopted in 2010 at Nagoya, is that "by 2020, invasive alien species and pathways are identified and prioritised, priority species are controlled or eradicated, and measures are in place to manage pathways to prevent their introduction and establishment". In addition, the Convention on the Conservation of European Wildlife and Natural Habitats commits contracting parties to control invasive species.[4]

3. The Nagoya target is also reflected in the EU biodiversity strategy: "By 2020, invasive alien species and their pathways are identified and prioritised, priority species are controlled or eradicated, and pathways are managed to prevent the introduction and establishment of new [invasive species]".[5] To help achieve this target, the EU is in the process of negotiating and agreeing aRegulation on the Prevention and Management of the Introduction and Spread of Invasive Alien Species.[6] This would apply to all invasive species other than where they alter their natural range without human intervention or where controls on them already exist in other European regulatory regimes.[7]The Government told us that the proposed regulation "addresses all of our objectives", and that the "consistent approach across the EU" it will produce "represents a considerable improvement on the current disjointed situation across Europe".[8]

4. In Great Britain, policy is coordinated by the Non-native Species Secretariat which brings together the environment departments and agencies of England, Scotland and Wales. The Secretariat is responsible for overseeing the 2008 Great Britain Invasive Non-native Species Framework Strategy.[9] Work to revise and update the Strategy has been underway since September 2013. The Secretariat would also have to coordinate any further requirements from the implementation of the proposed EU regulation.

Our inquiry

5. We made a commitment to examine the issue of invasive species in our 2013 report on Wildlife Crime.[10] We did so at this time because negotiations were underway in the European Commission on the proposed invasive species regulation and because the Great Britain Invasive Non-native Species Framework Strategy was being revised. We took oral evidence from 19 witnesses over four sessions, including academics, research bodies, NGOs, industry groups, regulatory bodies and Lord de Mauley, the Defra Parliamentary Under-Secretary of State for natural environment and science.

Defining invasive non-native species

6. A species is defined as native in Great Britain if it re-colonised after the end of the last period of glaciation.[11] Professor Chris Thomas of the University of York pointed out that not all of the animals and plants now seen in Britain were here 11,000 years ago, and since then species "have flowed back and forth across Europe".[12]Some supposedly non-native species, such as rabbits, were in fact present here in previous interglacial warm periods.[13] The proposed EU regulation defines a non-native species in terms of being "introduced outside their natural range".[14]It deals with species introduced by human intervention and excludes "species changing their natural range without human intervention, in response to changing ecological conditions and climate change".It requires that species which, based on available scientific evidence, are likely to have significant adverse impacts on biodiversity or related ecosystem services, should be placed on anEU'List of Species of Concern' (paragraph 24).

Effects on biodiversity

7. Dr Richard Shaw of the research group CABI suggested to us that invasive non-native species have biodiversity impacts distinct from invasive native species.[15] Dr Mark Spencer from the Natural History Museum noted that native invasive species are constrained by pathogens and predators, whereas non-native species are not. The Tree of Heaven from south-east Asian, for example, faces native British biodiversity with no "taste for that plant", allowing it "to spread like wildfire once the environmental conditions [here] are the same".[16] Professor Chris Thomas believed that some non-native species can cause widespread change to native species, citing the example of the replacement of the Red Squirrel bythe Grey over most of Britain, which was assisted by the spread of a shared disease (squirrel pox) to which Grey Squirrel is more resistant.He noted, nevertheless, that despite the influx of 1,875 non-native species, "we have not had any species-level extinctions from Britain" and that the empirical evidence suggested that if 1,000 more non-native species were added it would be only likely to result in the extinction of "a few" native species.[17]

8. Dr Helen Roy from the Centre of Ecology and Hydrology, on the other hand, told us that the 15% of invasive non-native species that do cause problems cause "extreme difficulties".[18] Dr Niall Moore from the Non-Native Species Secretariat also raised concerns from NGO Plantlife that Starfruit[19] was "probably going to become extinct" in Britain because of the invasive New Zealand Pygmyweed plant. The Tansy Beetle, which feeds on the Tansy plant that is being excluded from river banks by invasive Himalayan Balsam, could also become extinct in England.[20]

9. Biosecurity—the exclusion, eradication, and effective management of pests and unwanted organisms—is at risk from the importation of commodities and live plants and animals, and from international travel. Invasive species are often vectors for plant and animal disease.[21] Professor Chris Thomas noted that although some are significant—Ash Dieback and Bluetongue in sheep—there is a large number of other less severe non-native diseases which arrive but go unnoticed.[22] Defra is currently reviewing its approach to biosecurity,[23] for which the Food and Environment Research Agency has been commissioned to examine biosecurity policies in New Zealand and Australia for comparison.[24] New Zealand's Biosecurity Act 1993 and Biosecurity Law Reform Act 2012 emphasise the management of biosecurity threats offshore, in their country of origin.[25] Dr Richard Shaw from CABI told us that the New Zealand and Australian biosecurity model was significantly in advance of the rest of the world, but biosecurity in Great Britain was in advance of that in the rest of Europe.[26]

10. A difficulty for policy-making in this field is that any regulations to reduce biosecurity risks would need to comply with World Trade Organisation agreements and EU legislation. It also needs to integrate policies on invasive species and biosecurity. However, in the European Commission the Directorate General for Health and Consumers is responsible for the animal, plant and human health regulatory framework, while invasive species policy falls under the Directorate General for the Environment. The proposed EU regulation on invasive species is intended to be aligned with, but not overlap, existing EU legislation:It will not apply to the organisms targeted by over 40existing pieces of European legislation on animal health and plant diseases.

11. Coherence between the proposed EU regulations on invasive species and on Animal and Plant Health regimes would help improve understanding of the risks and increase compliance with the regulatory frameworks. The risks posed to biosecurity in Britain, as exemplified the Ash Dieback epidemic, make it imperative that an integrated approach is taken to managing the routes of biological invasion into the EU. The Government must engage with the EU's workin revising the Plant and Animal Health regulatory frameworks to ensure the result is a unified approach to biosecurity threats betweentheseregulatory frameworks and the invasive species framework.


12. The proposed EU Regulation would require member states with 'outermost regions' (which are fully part of the EU) to draw up lists of species of concern for those regions. It would not apply to UK Overseas Territories despite, as we noted in our recent report on the Overseas Territories,the Territories containing 90% of the biodiversity found within the UK and Territories combined,[27]and more globally threatened species than in the UK.[28] Invasive species are one of the primary drivers of biodiversity loss in the Overseas Territories. In many cases, we noted, there was a lack of surveillance and monitoring in the Territories, as well as weaknesses in environmental legislation, implementation and technical expertise. However, Lord de Mauley told us that the Overseas Territories' biosecurity issues had to be considered in the context of theirdistinct constitutional relationship with the UKand that Territory Governments were responsible for the protection and conservation of their natural environments.[29] That mirrored the thrust of the Government Response we subsequently received to our Overseas Territoriesreport.[30]

13. Given the vulnerability of biodiversity in the UK Overseas Territories to invasive species and its unique value, it is imperative that the Government assist the Territories to assess and address the pathways for newly arriving species. It should provide them with further support to address the most pressing gaps in their biosecurity frameworks and to draw up 'lists of concern' for the Territories in line with those that will be required for the EU 'Outermost Regions' by the proposed EU directive.

Adverse effects on ecosystem services

14. The lack of a framework for quantifyingthe effects of invasive species on ecosystem services (the beneficial goods and services we derive from habitats and biodiversity)[31] limits the Government's ability to predict when and where those effects will arise. Professor Chris Thomas argued that adding new species to ecosystems in Britain could increase their resilience to environmental change.[32] Others, however, identified risks to ecosystems. The Angling Trust told us how Himalayan Balsam affects fish in rivers: it excludes all the other flora from river banks, and when it dies back in the autumn there is heavy erosion and silting of the river.[33] Anglian Water found that the silting affected water quality and so increased the cost of water treatment.[34] Richard Shaw believed"the true costs to the country [of invasive species] are very high indeed".[35]Dr Helen Roy highlighted that some had an adverse "ecosystem engineer" effect, which was difficult to quantify.[36] The lack of a database on ecosystem effects means that habitats need to be monitored, as we discuss below.

Effects on human health and economic costs

15. Richard Shaw argued that every sector of society was affected by invasive species, at a large and increasing cost.[37] The European Environment Agency has estimated that the cost to the EU of a range of invasive species was at least €12 billion a year.[38] The Country Land and Business Association (CLA) highlighted three high-cost examples: £10million a year in damage to trees by grey squirrels, £1.5billion to eradicate Japanese Knotweed and £11million to eradicate Rhododendron from one national park in Wales alone.[39] The City of London Law Society calculated that the annual cost of dealing with Japanese Knotweed in Britain was £165 million, and that the cost of removing it from the Olympic site was £70 million.[40] The Angling Trust cited the North American Signal Crayfishand 'Killer Shrimp' which predates fish stocks, and plants such as Floating Pennywort which deprives fish of oxygen. The cost of water treatment increases when Zebra Mussels clog intake pipes.[41]

16. Some invasive species have direct human health effects. Anglers coming into contact with Giant Hogweed received skin inflammations.[42] The pollen of Common Ragweed causes asthma.[43] The Asian Hornet, which might soon arrive here, has killed six people in France.[44] TheOak Processionary Moth can cause respiratory and skin problems.[45]Dr Niall Moore told us that although human health was included in invasive species risk assessments, there was a case for including Public Health England on the Board of the Non-native Species Secretariat.[46] With a different perspective, Mark Spencer suggested to us that there was an over-emphasis on the impact of invasive species on wildlife habitats, when in fact new invasive species often have significant consequencesfor human well-being.[47]

17. There are potential human health effects from invasive species, not just biodiversity impacts.Public Health England should be integrated into the work of the Non-native Species Secretariat, to help it address human health and well-being considerations.

A changing environmental baseline

18. The approach taken to invasive species needs to be considered in the context of wider environmental change.[48] Dr Mark Spencer highlighted that habitats which were "heavily impacted by humans in adverse ways are often much more vulnerable to biological invasions".[49]With environmental changes increasingly being caused by human activities, it would be ever more difficult to identify a change in a species' range that was caused by only natural factors. He suggested, therefore, that reponses to non-native species might need to become more nuanced in the future.[50] Professor Chris Thomas argued that with three-quarters of species having already shifted their distributions because of climate change, conservation had to be increasingly about managing major changes which were already happening.[51] Many insects were arriving and plants were already being grown in our gardens, he said, which were "likely to be a major source of new species effectively becoming wild in Britain".[52] He told us:

    we are going to have new biological communities from separate species we have not had before. I would encourage people not to take an "any change is bad" attitude, but to say, "let us try to identify the fights that we wish to engage in", defined by whether they cause major changes that we are not happy about, and whether the fight is winnable. [53]

Chris Thomas believed that any strategy or legislative framework should not result in controls which impaired conservation for species threatened by climate change.[54] He told us:

    … we are risking, by our actions on repelling foreign species, inadvertently increasing the global extinction rate over what we could achieve. If there is a certain number of species, let us say restricted to local areas in Southern or Central Europe that are truly endangered by climate change, if we bring them here and potentially save some of them, it would not work for all of them, and it will have some impacts on native things.[55]

Lord de Mauley told us, however, that the Government was not yet at the point at which it was:

    wholeheartedly welcoming new species because our existing species are dying out because of climate change. We are focused at the moment still on preventing new invasions and on tackling, to the extent that we can, and controlling those that we have here.[56]

19. Environmental changes caused by humans, including through climate change, are affecting the global distribution of species. One aspect of climate change adaptation will be a need to increasingly focus on conservation, where changes in species distributions have to be managed rather than simply resisted. That will determine over the years ahead the need for, and realism of, the measures put forward by the proposed EU directive, which we discuss below in Part 2.

20. The Government should use the opportunity of the ongoing revision of its Non-native Species Strategy to begin a public debate on the implications of changes in our biodiversity and ecosystems driven by still increasing climate change and international trade, including our approach to nature conservation.

1   Helen Roy et al, Non-native Species in Great Britain: Establishment, detection and reporting to inform effective decision making (2012) Back

2   World Resources Institute, Millennium Ecosystem Assessment: Ecosystems and Human Well-being: Biodiversity Synthesis(2005) Back

3   UN, Convention on Biological Diversity, Article 8(h) Back

4   UN, Convention on Biological Diversity, Article 11 Back

5   European Union, EU Biodiversity Strategy to 2020 (2011), target 5 Back

6   European Commission, Draft Regulation on the prevention and management of the introduction and spread of invasive alien species (2013) Back

7   ibid Back

8   Lord de Mauley (IVS 021) Back

9   Defra, Great Britain Invasive Non-native Species Framework Strategy (2008) Back

10   Environmental Audit Committee, Third Report of Session 2012-13, Wildlife Crime, HC 140 Back

11   POST, Invasive Alien Plant Species (POSTNote 439) (July 2013) Back

12   Q170 Back

13   Q189 Back

14   European Commission, Draft Regulation on the prevention and management of the introduction and spread of invasive alien species (2013), Article 3 Back

15   Q19 Back

16   Q20 Back

17   Qq178, 183 Back

18   Q23 Back

19   Damasonium alisma, a pond plant in Britain restricted to two sites on Berkshire heaths and one Surrey heath site. Back

20   Q196 Back

21   Q11 Back

22   Q191 Back

23   Defra (IVS0011) Back

24   Fera, Australia and New Zealand Biosecurity Review (2013) Back

25  Biosecurity New Zealand, Review of Key Parts of the Biosecurity Act 1993(2009) Back

26   Q7 Back

27   Foreign and Commonwealth Office,Overseas Territories: Security, Success and Sustainability, Cm8374, June 2012, p8 Back

28   International Union for Conservation of Nature Red List of Threatened Species,, accessed 8 April 2014; POSTNote 427, Biodiversity in UK Overseas Territories, (January 2013);Jérôme Petit and Guillaume Prudent (eds),Climate Change and Biodiversity in the European Union Overseas Entities, International Union for Conservation of Nature 2010, p17 Back

29   Q269 Back

30   Environmental Audit Committee, Eighth Special Report, Sustainability in the UK Overseas Territories. Government Response to the Committee's Tenth Report of Session 2013-2014, HC 1167 Back

31   Montserrat Vilá, Corina Basnou, Petr Pyšek, Melanie Josefsson, Piero Genovesi et al, How well do we understand the impacts of alien species on ecosystem services?,Frontiers in Ecology and the Environment, vol 8 (2010), pp135-144 Back

32   Q186 Back

33   Q79 (see also Robert A. Tanner, Sonal Varia, René Eschen, Suzy Wood, Sean T. Murphy and Alan C.Grange,Impacts of an Invasive Non-Native Annual Weed, Impatiens glandulifera, on Above- and Below-Ground Invertebrate Communities in the United Kingdom, PLoS ONE, vol 8 issue 6 (2013), e67271) Back

34   Q80 Back

35   Q4 Back

36   Q4 Back

37   Q3 Back

38   European Environment Agency, The impacts of invasive alien species in Europe, Technical Report No 16/2012, p6 Back

39   Q78 Back

40   City of London Law Society (IVS002) Back

41   Q80 Back

42   Q79  Back

43   Jordina Belmonte and Montserrat. Vilà, Atmospheric invasion of non-native pollen in the Mediterranean region, American Journal of Botany, Vol 91 (2004), pp1243-1250 Back

44   Q219 [Niall Moore] Back

45   Q217 [Adrian Jowett] Back

46   Qq220, 221 Back

47   Q3 Back

48   Andrew S. MacDougall and Roy Turkington, Are invasive species the drivers or passengers of change in degraded ecosystems? Ecology, Vol. 86, Issue 1 (2005), pp42-55 Back

49   Q14 Back

50   Q27 Back

51   Q184 Back

52   Q186 Back

53   Q189 Back

54   Q192 Back

55   Q185 Back

56   Q256 Back

previous page contents next page

© Parliamentary copyright 2014
Prepared 16 April 2014