Norfolk Non-Native Species Stakeholders’ Forum 2012


Photo of a previous Stakeholders Forum
(Photo credit: Mike Sutton-Croft)

1)To update stakeholders on the latest developments regarding invasive non-native species at a national level, and emerging issues.

2)To inform stakeholders of progress made by the Norfolk Non-native Species Initiative over the past year.

3)To foster an exchange of ‘best practice’ management experience amongst stakeholders in Norfolk.

4)To encourage networking among diverse range of organisations and stakeholders with an interest in controlling invasive species in Norfolk.

5)To provide stakeholders with up-to-date information on potential legislative changes relating to invasive non-native species, and an opportunity to comment on these changes.

The potential for biological control of Himalayan balsam – Dr Rob Tanner, CABI (Agricultural Bioscience International)

Non-native species have an unfair advantage

Non-native plant species arrive in the exotic range without the natural enemies that keep them in check in their native range. Native species that do attack/feed on them do not cause enough damage to reduce their presence. Research, and numerous ‘real world’ releases, have demonstrated that some of the many insects and diseases in the native range can be safely used as biological control agents.

Biological control

There are three main types:

Inundative - The mass production and periodic release of large numbers of bio-control agents to control a pest

Conservation - Modification of the environment or existing practices to protect and enhance specific natural enemies or other organisms to reduce the effects of pests.

Classical (CBC) - The utilisation of co-evolved natural enemies in the regulation of host populations.

Himalayan balsam

Himalayan balsam (Hb) is a huge problem, degrading native habitats and costing significant amounts of money to control each year. To investigate the impacts of the species in more depth, CABI carried out a comparative study on the abundance of invertebrates found on Hb compared with native vegetation. The results of this study revealed that native vegetation has a significantly higher number of invertebrates living on it.

Dr Tanner explained that rust fungi have commonly been used as a biological control agent across the world, and one species from Hb’s native range looks a good candidate to be utilised in the UK - Puccinia komarovii. This highly damaging potential agent attacks the stem and leaves of the plant often killing the young seedlings and reducing the photosynthetic rate of older plants during the dispersal phase of the pathogen (CABI, 2012). Host specificity testing is ongoing, and should this be completed successfully, the rust fungus could be tested in the field in the near future.

Japanese knotweed

Japanese knotweed is one of the most damaging invasive weeds in the UK. It is estimated that the control of Japanese knotweed costs the UK over £150 million per year, with either spraying or injecting herbicide being the most common control methodologies.

The use of a biological control agent for Japanese knotweed could mean that the cost of eradication would be significantly reduced. CABI are currently undertaking Government approved releases of a specialist psyllid as a biological control agent for Japanese knotweed in the UK. After a number of years of research in Japan and the UK, it has been established that this tiny, sap-sucking insect is a Japanese knotweed specialist and can only complete its development on the plant (it cannot survive without it). Dr Tanner said that the risk of damage to native plant species was extremely low. The releases are taking place in a number of field trial sites in England and Wales. These sites are currently being monitored, with the impact of the insect on Japanese knotweed being recorded.

New Zealand pygmyweed and floating pennywort

Other investigations CABI are undertaking includes the biological control of the invasive semi-aquatic plant New Zealand pygmyweed Crassula helmsii and aquatic floating pennywort Hydrocotyle ranunculoides. Surveys conducted in New Zealand, Victoria and Tasmania resulted in the discovery of several insect species which cause significant damage to the stems of New Zealand pygmyweed. Testing is ongoing. Various natural enemies have been found in Argentina for floating pennywort, both insect and fungal.

The New Forest Non-Native Plants Project – tackling the challenge (with a focus on New Zealand pygmyweed Crassula helmsii) – Catherine Chatters, New Forest Non-native Plants Project

The New Forest Non-Native Plants Project was set up in 2009 to reduce the spread of invasive non-native plants. Species present in the New Forest include Himalayan balsam, parrot’s feather, giant hogweed, New Zealand pygmyweed Crassula helmsii, American skunk cabbage, Japanese knotweed and creeping water primrose.

It is a partnership project, hosted by the Hampshire & Isle of Wight Wildlife Trust with support from the Environment Agency, Forestry Commission, Natural England, DEFRA and the New Forest National Park Authority. The New Forest Non-native Plants Project actively engages with landowners to spread good practice techniques and provide advice and practical help where appropriate. 

An up-to-date picture of the distribution of invasive non-native species in the New Forest is very important. Many of records are obtained from visitors to the New Forest.

The New Forest Non-native Plants Project is working to raise awareness about invasive non-native species through the media, including the press, radio and local television shows. The Forestry Commission is also helping to raise the profile of invasive non-native species, and specifically the issues caused by the fly tipping of garden refuse.

The New Forest Non-native Plants Project works to promote the ‘Be Plant Wise’ Campaign, both by encouraging retailers to display the ‘Be Plant Wise’ leaflets and posters, and by directly educating the general public about invasive species.

Volunteers have been carrying out research, monitoring and surveys of invasive non-native plant species. One of the investigations they carried out was on American skunk cabbage, testing the effectiveness of various herbicide treatments.

Research into the removal of New Zealand pygmyweed

Research into New Zealand pygmyweed Crassula helmsii and the possible methods to eradicate the plant has been a high priority. After baseline surveys had been conducted it was agreed that the eradication methods of hot organic foam, aquatic dye and herbicide would be trialled across the New Forest.

Hot organic foam

Application of the hot foam proved to be time consuming, with only limited mortality of New Zealand pygmyweed observed. A positive result was that the foam did not affect native plant species in the forest, including shoreweed which was seen to be growing during monitoring after application. 

Aquatic dye

Treatment involved pouring a dark coloured dye into the water where New Zealand pygmyweed grew. The dye blocks out certain colours in the light spectrum so that the plant is unable to photosynthesise properly. Unfortunately the trials were also not very successful; possibly as a result of a significant amount of rainfall shortly after the plant was treated with the dye.


Kingcombe AquaCare Limited utilised Round up to control the plant. The results of this experiment were not disclosed. 

In instances where the eradication method was unsuccessful or compromised it is being trialled again to obtain more representative results. Findings will be published at a later date.

How will non-native fishes and riverine food webs n the U.K. respond to climate change? – a few case studies – Prof. Gordon Copp, CEFAS

It is important that we understand more about how climate change could affect our ecosystem.

Forecasting and prediction

Forecasting and prediction is important. By forecasting and predicting which new species might arrive under current and future conditions we can understand more about them and, if required, how to stop them.

Forecasting the response of some Ponto-Caspian species to climate change has already been undertaken and papers written. These species have been identified as being of particular concern. 

Ponto-Caspian species

Species from this area are noted as being of particular concern, and that is why they were used in this study. Other Ponto-Caspian species in the UK that are causing problems include the zebra mussel and killer shrimp.

Research was carried out on a small number of fish species to see how climate change would affect them. One of six extant non-native fish species predicted to benefit from climate change is pumpkinseed, introduced in more than 28 countries worldwide. Other species studied include goldfish, fathead minnow, European catfish, common carp and bitterling.

Background on pumpkinseed

The model species, pumpkinseed, has a distinct life. Males are nest guarders and females are batch spawners. Growth and age at maturity are influenced by local environmental conditions.

How will pumpkinseed spawning respond to climate change?

The spawning ability of pumpkinseed was tested in response to the predicted effects climate change would have on the species. 

Conditions: Testing took place in 6 lined ponds, designed so that each had a shallow end for nesting.

Aims of the study 

  • Assess the potential for increased reproductive output by comparing under ambient versus climate warmed conditions, timing and duration of the reproductive period in pumpkinseed, the frequency of female visits to nests (defended by males) and the amount of time females spend at nests


  • Increases in temperature (waters ≈ 2–3 °C)
  • Increased frequency of spates and floods
  • Hence, increased connectivity between floodplain waters and water courses

Results – pumpkinseed

  • No difference in the duration of reproductive period
  • No difference in the frequency of female visits to nests
  • No difference in the amount of time females spend at their nest.

It was found that that the pumpkinseed spawned earlier in the heated ponds, with a longer pre-winter period of year on year growth and bigger fish year on year. This could be expected to enhance fitness and increase the survival rate of the fish.

Does pumpkinseed impact Eurasian perch growth under current and future climate conditions?

Roule (1928) made the assumption that the species interactions change under warmer climatic conditions. Gordon and his team tested this theory and studied the interactions between pumpkinseed and Eurasian perch.

Habitat background of Eurasian perch and pumpkinseed

The pumpkinseed and Eurasian perch live in different environments, although both live in the littoral zone. Pumpkinseed like warm water and outcompete yellow perch. Eurasian perch on the other hand live in cool water. They are functionally the same as the yellow perch.

Conditions: Testing took place in six artificial ponds. Three were ambient temperature and three were artificially heated (2 – 3 degree increase). Weekly invertebrate samples were taken.


From the testing it was found that pumpkinseed could live with Eurasian perch as they occupied different niches. 

Tests on food abundance versus performance were carried out and, as expected, results showed that as food abundance went down so did performance. When food abundance was increased performance increased. Diet analysis indicated that there were dietary shifts when the species lived together.

Prediction of ecological impacts on temperate freshwater ecosystems arising from climate change and non-native species introductions

Three objectives:

  • Test for ‘keystone’ species
  • Examine non-native impacts (NNS, translocated)
  • Examine climate warming impacts on the food web

A food web model was created. Different species were removed at various times and it was found that there were no keystone species present to create a shift in the environment. 

A non-native top predator was put into the testing environment and was found to have a moderate impact. There was no negative impact after the addition of a larger-bodied species at an intermediate trophic level. The largest impact came when a small competitor was added at medium and high trophic levels.

After testing the affects of climate change (increase in temperature) the general consensus was that the ecosystem model was considered fairly resilient to most of the tested disturbances, possibly owing to the high natural variability of the community.


Pumpkinseed growth and recruitment

Earlier spawning equals a longer year on year pre-winter somatic growth.

Expected to enhance fitness and increase survival rate.

Pumpkinseed versus Eurasian perch growth

Roule’s (1928) assumption was not validated, there were no growth impacts.

The growth of the two species was similar or enhanced in sympatry.

Repartition of available food.

Summary of the Comenius Regio ‘INSTINCT’ Project between schools in Norfolk and Haute-Savoie – Mr Adrian Tebbut

The project is funded by an EU Comenius Regio grant, obtained through the British Council. The project is led by Norfolk County Council in England and in France by the equivalent regional body, the Conseil General.

It is an educational science project involving three schools in Norfolk and three from the Haute-Savoie in the French Alps. The programme is supported by scientific educational partner organisations in both countries.

Achievements to date and our plans for the future – Mike Sutton-Croft, NNNSI Co-ordinator

Mike Sutton-Croft, the NNNSI Co-ordinator, gave a brief update of the activities of the project since the previous Forum. 

Broad Sweep and Pond Invaders surveys

The ‘Broad Sweep’ Citizen Science Survey has been successful, and it is now time for the NNNSI to launch their NEW ‘Pond Invaders’ Citizen Science Survey. 

The ‘Pond Invaders’ survey feature the highly invasive aquatic plant species water fern, New Zealand pigmyweed, parrot’s feather, creeping water primrose and floating pennywort.

The leaflet has been distributed to garden centres in west Norfolk and displayed at events. People who recognise that they have any of the species that are featured in the leaflet in their garden pond can submit their records of invasive alien species online, by mail or over the phone. The survey is in its early stages but the NNNSI ultimately hope to build a map of invaded garden ponds across Norfolk. From the success of the ‘Broad Sweep’ survey and the positive reaction to the ‘Be Plant Wise’ campaign we anticipate that we will receive lots of records, providing us with a database of information which could be used to identify why they might be being found where they are in the wild.

Smartphone App

During the summer of 2011 the NNNSI trialled a smartphone App to record invasive non-native species. Mike Sutton-Croft stated that the App was a very useful piece of technology that can currently identifies five invasive alien species with the hope to increase this number in the near future. Through a new project, Reducing Invasive Non-native Species in Europe (RINSE), the NNNSI now has funding to develop a fully functional recording App that should be available for the summer of 2013.

The FINAL year of the ‘Invasive non-native aquatic plants of Norfolk: Status Report and Plan of Action for six priority species (2009-2013)’

Mike Sutton-Croft emphasised that half of the proposed action plans have been carried out and completed, half are underway, with none that had not been started.

High priority sites for eradication projects in Norfolk have been targeted and many have treatment underway 

The River Wensum Himalayan balsam Eradication Project is well underway. Alert leaflets were posted by Natural England to residents in the River Wensum catchment early this year, and in July 2012 the NNNSI, volunteers and contractors will start removal work at the worst affected sites. The NNNSI hope to eradicate the species from the River Wensum catchment by 2014.

Two ponds containing New Zealand Pigmyweed Crassula helmsii at Mile Cross marsh in Norwich were targeted as a high priority site for eradication as a result of their proximity to a SSSI. The two infested ponds were filled in and five new ponds were created in a more suitable location. Pond Conservation was consulted throughout the project so as to create ponds with the greatest wildlife benefit.

Water primrose Ludwigia grandiflora a highly invasive alien aquatic plant was discovered during an ecological survey to support a planning application in 2010. The Council’s District Ecologist reported this to the NNNSI Co-ordinator and following a site survey water primrose was removed from the site swiftly and effectively.

White-clawed Crayfish ‘Ark’ site 

The River Glaven in north Norfolk was once a white-clawed crayfish stronghold and haven, however in recent years the river has been invaded by the vicious invasive non-native signal crayfish. The species carries ‘crayfish plaque’ of which kills white-clawed crayfish. Following an aborted attempt to eradicate signal crayfish from the River Glaven the focus turned to establishing an ‘Ark’ site. A survey of the River Stiffkey revealed that it was an ideal habitat for white-clawed crayfish. Landowner permissions and the required licences for the translocation were obtained, and in September 2011 300 healthy white-clawed crayfish were translocated to the River Stiffkey in north Norfolk. The NNNSI hope to co-ordinate another translocation in September this year.

Ongoing projects…

  • Eradication of Floating Pennywort on the River Waveney
  • Control of giant hogweed of the River Yare
  • Eradication of parrot’s feather at Sutton
  • Eradication of Japanese knotweed at Fakenham
  • Eradication of giant hogweed on the River Nar

‘Be Plant Wise’ Campaign

In September 2010, the NNNSI was informed by the GB Non-native Species Secretariat that their application for a £500 grant to support activities to promote the ‘Be Plant Wise’ public awareness campaign had been successful, and in November 2010 the NNNSI began promoting the campaign.

Through the activities of the NNNSI distributing ‘Be Plant Wise’ materials to aquatic retailers and to the public at events, thousands of individuals in Norfolk will have been exposed to the ‘Be Plant Wise’ campaign and its core messages; know what you grow, compost with care and prevent the spread. It is hoped that by targeting the major aquatic plant retailers in the area the messages will reach pond owners, and make them aware of the potential impacts of disposing of their pond plants inappropriately. This should help to prevent further introductions of invasive non-native aquatic plants in to the wild in Norfolk.

Check Clean Dry Campaign

The Check Clean Dry campaign is essential to prevent the spread of killer shrimp (Dikerogammarus villosus). It was launched in April 2011 to promote good bio-security amongst waterbody users. The NNNSI along with the Environment Agency and the Broads Authority have distributed Check Clean Dry information leaflets to boat hire shops, angling shops and tackle shops, as well as displaying Check Clean Dry banners at events. The NNNSI coordinator also produced a Check Clean Dry guide for contractors working in/near waterbodies.  

Events and Media Coverage

Each year the NNNSI goes to many events across Norfolk to educate the public on invasive non-native species.  As ever the NNNSI stand has been very popular with the public. Good practice has been a main focus over the past year, now that people are more aware of what invasive non-native species are and what they look like, they want to be able to carry out control programmes on species in their garden. It is imperative that people can ID the species, know how to control them and dispose of them correctly; this way species are less likely to find their way into the wild.

Awareness of invasive alien species has been raised through the local media, including coverage on local radio and BBC Look East. Aerial images of the Himalayan balsam around Surlingham Broad in Norfolk were broadcast on the news as was the NNNSI Co-ordinator Mike Sutton-Croft, describing the impacts of invasive non-native species.

Reducing the Impact of Non-native Species in Europe (RINSE)

Mike Sutton-Croft NNNSI Co-ordinator recently took on the new role as RINSE Technical Co-ordinator, of which Norfolk County Council is lead partner.

RINSE is an exciting new European Project seeking to improve the management of invasive non-native species (INS) across four partner countries (nine partner organisations) in Western Europe. RINSE will also increase awareness of the threats posed by INS, and the most effective methods to address them. The project has been part funded by the European Union and delivered through the Interreg IVA Seas Programme. 

RINSE will work across borders to share best practice and adopt strategic approaches to tackle the threats posed by INS. The project will look at invasive non-native plants, birds, fish and mammals in various habitats. 

The programme will work to carry out its three work packages:

  • Targeting and Prioritisation
  • Training and Awareness Raising
  • Field Trials and Demonstration Projects

Direction for the NNNSI

The NNNSI’s strategic direction is now being re-assessed, taking into account the work being carried out under RINSE and other opportunities.

Invasive shrimp in the Broads - Andrea Kelly, Broads Authority

Killer shrimp Dikerogammorus villosus is an invasive non-native shrimp. It has spread across Europe using migration corridors from the Ponto Caspian Region of Eastern Europe.

The UK has the right bioclimatic suitability for killer shrimp, as is demonstrated by the locations it is currently found.

There are currently four known sites where killer shrimp is resident. These are:

  • Grafham Water (SSSI), Cambridgeshire on 3rd September 2010
  • Cardiff Bay 25th November
  • Eglwys Nunydd Reservoir (Port Talbot), in Wales on 26th November 2010
  • Barton Broad (Norfolk Broads) (River Ant) on 7th March 2012

Habitat of killer shrimp

The sites listed above are desirable habitats for killer shrimp. Below is a list of habitat requirements. It is important to recognise that not all of The Broads has the same habitat conditions and therefore the killer shrimp will only live in areas best suited to them.

  • Stones, cobbles and tree roots
  • Zebra Mussels – not associated in all locations (Dutch Ijsselmeer) (also from Ponto-Caspian region)
  • Temperature – tolerates 35 degrees
  • Flow can be a barrier
  • Salinity – can tolerate up to 20ppt


The key to identifying the killer shrimp is to see if it has two cones (spikes) near its tail, if these are present it is likely to be killer shrimp.

Killer shrimp has directly and indirectly affected the water bodies it now inhabits. 

Direct ecological effects

  • Predation - decline in macroinvertebrates (e.g. native shrimps, mayflies, damselflies, leeches, chironomids, cladocera and snails
  • Predation - fish eggs and larvae (Bullhead)
  • Ecosystem effects – less leaf processing and impacts on nutrient dynamics

Indirect ecological effects

  • Increase of some species, through the reduction of predators or the creation of a new food response
  • May be affecting the likelihood of catching fish
  • Possible intermediate host for parasites of salmonid fish

What has been done about the killer shrimp?

Authorities, including the Broads Authority and Environment Agency, are all working together to carry out surveillance and monitoring in the affected areas of the Broads, as well as the areas that are susceptible to invasion by the shrimp. They are trying to contain the species, advise water users on good practice (Check, Clean, Dry campaign) and raise awareness about the impact the species could have on the Broads ecosystem. 

Communication is crucial, the authorities have been spreading the words of the Check, Clean, Dry campaign (there are lots of sources of information on the internet and GBNNSS website), created to inform people on what do when they remove their equipment from the water, so as to prevent the spread of the species to new locations and to educate people about good bio-security. 

Check, Clean, Dry

Check boats and fishing kit

Clean all equipment

Dry equipment for 2 days

Current and Future Plans

As a result of the invasion of killer shrimp a Bio-security Officer has been appointed at the Broads Authority to undertake all work on killer shrimp and other bio-security threats when they occur.

Carry on monitoring the Broads area and investigating the species.

Killer shrimp doesn’t harm humans. It is not known if the shrimp is edible and Andrea would like to hear from anybody who has or wants to try!

If you find the shrimp email: (Please include Location/date/photo)

The Law Commission review of Wildlife Management Law – Keith Vincent, The Law Commission

The Law Commission was established in 1965 to review the law with a view to its simplification and modernisation.

‘The Wildlife Project’ was proposed by DEFRA, its consultation is July to November 2012 and conclusions are to be with DEFRA by February 2013. A report and Bill will be produced by spring 2014.

The approach to the project covers species protection, welfare, exploitation, control of invasive non-native species and enforcement/procedure (including appeals). It will not include the Hunting Act 2004. It will not make species protection judgements.

What is the problem with the current regime?

The nature of the current regime is complicated, including the number of Acts

The approach to transposition of EU Directives

Inflexibility of the current regime, such as the lack of licensing provisions in certain Acts

Lack of clarity in the current regime

Gaps in the current regime, such as powers for the control of invasive non-native species

Basic features of ‘The Wildlife Project’

A single Act? Inclusive for all species? 

Simplified legal regime, encouraging understanding of rights and obligations

Species sorted by listing, giving species specific legislative regimes

Regulatory approach

The Principal regulatory approach is where species scheduled prohibit certain activity, provide defences; and licence. However, a wider range of techniques can be used, such as approved codes of practice (for, by way of example, forestry or agriculture).

Reforming criminal offences relating to wildlife

It could be said that there is a need for a simplified criminal regime; the nature of the current regulatory regime is complex, by having a simplified criminal regime enforcements could be made more easily. Could there be a greater use of civil sanctions? For example taking health and safety as the model.

Control of invasive species

Currently it is only an offence if you knowingly cause a species listed in the Wildlife and Countryside Act 1981 to spread into the wild. 

The legality of the situation is currently complex and very different to conservation laws. 

In the future there may be changes to EU law relating to invasive non-native species.

Scotland has recently made some major reforms to the Wildlife and Natural Environment (Scotland) Act 2011. These have bought about new laws concerning invasive non–native species. For example, provisions have been made to enable relevant bodies to issue a species control order if required. A species control order can be issued if the landowner has failed to carry out an operation required.  When this occurs the owner of the property with an invasive non-native species will then be given 42 days to enter into voluntary agreement to control and eradicate the species, if they do not co-operate eradication can take place without the permission from the landowner.

The role of Convention on Biological Diversity must be considered in all decisions relating to invasive non-native species.

Control of invasive species (2)

There is a need to reform the definition of invasive non-native species

The approach to invasive species is yet to be decided. Should it be dangerous, safe or something in the middle? Changes definitely need to be made; an approach that is too soft could mean that there are hardly any noticeable changes, with little to no enforcement. The approach needs to be practical, with enforcement possible at national as well as local levels.

Emergency listing could be an option for control of invasive non-native species

Expanded offence: “escape” of plants

Possibility of a flexible “toolkit”: permit; agree; order

Powers needed, and time-limits for action

Open discussion session 

Topics discussed

The need for a universal definition

Problems with only doing species management

Proving beyond reasonable doubt

When does something become termed invasive?

Will species that have been a problem for a long time be on the list?

White (good species) and black lists (bad species)

Social/economic species, how much are they costing us?

The need for smart legislation (change when it requires updating)

Will the species lists be flowing and changeable? Emergency lists?

Powers needed and time limits for actions