Andrea Griffiths BSc HONS Partnership Officer Medway Valley Countryside Partnership. Medway Valley Countryside Partnership

Transcription

1 Medway Valley Countryside Partnership Giant Hogweed and Invasive Non Native Plant Project Medway Catchment and River Cray 2013/2014 Report Andrea Griffiths BSc HONS Partnership Officer Medway Valley Countryside Partnership 1

2 Contents: 1. Introduction Pg Target plant information 2.1 Giant Hogweed Pg Floating Pennywort Pg Water Fern Pg Japanese knotweed Pg Himalayan balsam Pg Overview 3.1 Overview - Plant treatments Pg Plant treatments and data in 2013 and 2014: 4.1 The River Medway Pgs The River Beult Pg The Greater and Lesser Teise Pgs Gibbs Brook Pg The River Cray Pg Awareness Raising, Training, Communication and Volunteers Pg Future requirements Pg Project Finances Pg Contact Information Pg. 22 2

3 1.0 Introduction: Medway Valley Countryside Partnership (MVCP) work in the boroughs of Tonbridge and Malling and Maidstone to conserve, enhance and protect the local countryside for the benefit of both local people and biodiversity. As part of a larger Kent County Council Countryside Management Partnership family, MVCP work on a wide variety of conservation and access projects, working in partnership with many other organisations, linking in with local parish and borough councils and liaising with landowners. Going beyond their geographical work delivery borders, MVCP have been managing the Giant Hogweed and Invasive Plant Project in the Medway Catchment for 14 years. In that time the project has grown from location specific treatments of invasive plants to the catchment wide project which it is today. Annually, the project now covers around 200km of riparian habit and includes all of the Medway from East Sussex to Aylesford and the tributaries; Beult, Teise, Lesser Teise and Gibbs Brook (Surrey). The project also now covers the River Cray. (Map 1 showing river systems (with the exception of the River Cray) included in the project MVCP Where and when required, MVCP also address additional species such as Floating Pennywort, Japanese knotweed and Himalayan balsam. awareness raining and local training. The project supports the involvement of volunteers and includes This report details the activities of the project in 2014 (and briefly for 2013), highlighting the achievements and future requirements. 3

4 2. Plant Information: The project has expanded greatly over the last few years and now a number of plants are targeted in MVCP s work, not just Giant Hogweed. To reflect this the following few pages give an introduction to each of MVCP s target plants and the issues they create which warrant and justify their control. 2.1 Giant Hogweed (Heracleum montegazzianum) Giant Hogweed is a very invasive plant which was introduced to the UK as an ornamental garden plant but was then recorded in the wild from the late 19C. It is very invasive, with each plant potentially releasing 50,000 seeds each year. Seeds spread along water courses or can be spread by the wind. It grows aggressively, shadowing other native plants, causing bank erosion when it dies back and thus increases flood risk. Contact with any part of the plant should also be avoided as it s sap is toxic and can damage the skin, making the skin blister and be sensitive to sunlight. The physical effects of contact with the plant can last for a long time. Giant Hogweed is listed under Schedule 9 of the Wildlife and Countryside Act 1981 and it is also classed as a controlled waste under the Environmental Protection Act Giant Hogweed by the Medway in 2011 MVCP 4

5 2.2 Floating Pennywort (Hydrocotyle ranunculoides) As a result of irresponsible discard from pond waste, this plant began growing wild in the UK in It is a priority species for control as it is highly invasive - growing at a rate of 20cm a day. It forms dense mats on the surface of water bodies and can restrict access and recreation as well as reduce the light and oxygen levels of the water environment. It also outcompetes native plants. Floating Pennywort is listed under Schedule 9 of the Wildlife and Countryside Act Floating Pennywort mat on pond close to the Medway in 2012 Brian Thomas (MVCP) 2.3 Water Fern (Azolla filiculoides) This very small plant can form dense mats of floating vegetation and is highly invasive, spreading vegetatively and sometimes by spores. It outcompetes native species and the dense mats reduce light and oxygen below the surface causing deoxygenation and stopping air breathing insects from surfacing. It can also be a hazard as dense mats can appear solid. Water Fern is listed as Schedule 9 of the Wildlife and Countryside Act 1981 (Left) Water Fern GBNNSS 5

6 2.4 Japanese knotweed (Fallopia japonica) The effects of Japanese knotweed have been well documented in the media. Being very hardy, it can damage buildings and infrastructure and if present can delay and increase costs for development. Along rivers it can outcompete native flora and damage riverbanks, increasing erosion and flood risk. It spreads vegetatively and even a minute amount of stem can create a new stand. As such, irresponsible compost or garden waste dumping and also poor management such as strimming and cutting have greatly increased the spread. It is common in urban areas, gardens, along railway lines and adjacent to rivers. Japanese knotweed is listed under Schedule 9 of the Wildlife and Countryside Act 1981 and it is also classed as controlled waste under the Environmental Protection Act (Opposite) Japanese knotweed GBNNSS 2.5 Himalayan Balsam (Impatiens glandulifera) A tall annual plant which was introduced to the UK in the 19th Century for it s attractive flowers. Due to a very effective explosive seed dispersal method, it is now very common and widespread. It outcompetes sensitive native riparian flora. When dense it can impede flow along rivers and ditches and when it dies bank it compromises riverbanks, causing erosion and therefore increases the risk of flooding. Himalayan balsam is now listed as Schedule 9 of the Wildlife and Countryside Act 1981 MVCP volunteers removing Himalayan balsam from the side of a stream in 2011 MVCP 6

7 and 2014 Overview: In the calendar year of 2014 to date (25th Sept 2014) the MVCP Partnership Officer in charge of the project has spent 250 staff hours on the Giant Hogweed and Invasive Flora project. Work has been on the planning and supervising of the plant treatments, organising the survey data, liaising with landowners, planning training and events for volunteers and awareness raising by writing project newsletters and delivering lectures and presentations. Below is an overview of the plant treatment work. Section 5 (Pg. 20) is an overview of the other elements delivered such as Awareness Raising and Volunteer involvement. A significant amount of work is still required in this financial year. 3.1 Overview - Plant treatments and surveying: 120 landowners were contacted directly (both 2013 and 2014) about including their land in the MVCP scheme in case Giant Hogweed and any other target flora was observed and needed treating. Environment Agency support and permission to spray was granted for multiple years. Natural England support and permission to treat plants on the River Beult SSSI also granted. 200km (approx.) of riparian habitat was covered by MVCP s contractor to chemically treat Giant Hogweed in both 2013 and In 2013, 14,605 Giant Hogweed plants (approx.) were treated and recorded throughout the Medway Catchment and River Cray In 2014, 9000 Giant Hogweed plants (approx.) have been treated and recorded throughout the Medway Catchment and River Cray. Several treatments of Floating Pennywort were carried out at the source location and on the Medway near Yalding in both 2013 and 2014 (treatment still ongoing in 2014). Water Fern surveying on the River Beult was done in Funds for Water Fern Bio-Control were re-allocated to Medway Swale Estuary Partnership (MSEP) in MVCP also assisted MSEP with funds (via DEFRA funding) for Japanese knotweed and New Zealand Pigmyweed treatment. MVCP surveyed the Medway tidal section for Invasive Plants in July MVCP noted an increase in Japanese knotweed (JKW) in the River Teise in 2014 and with additional funds treatment of all of the JKW on the Teise is to be undertaken in September/October

8 Below is a map showing all the areas where MVCP have carried out Giant Hogweed treatment in 2013 and The red markings highlight plants which have been treated and controlled. Note the river Cray location outside of the Medway Catchment near Dartford. Also note the Gibbs Brook location near Redhill in Surrey. The other main areas are the River Teise, Lesser Teise, Beult and the main River Medway. This map shows the extent of the work carried out in geographical terms and highlights the importance of this ongoing project. Map 2 showing the overview of the Giant Hogweed treatment locations in 2013 and 2014 MVCP 8

9 4. Plant treatments and data in 2013 and 2014: 4.1 The River Medway: Treatment of Giant Hogweed plants on the River Medway (and the nearby Wateringbury Mill Stream) took place over several days in March and April in 2013 with some additional sprays undertaken in June. In 2014 treatment took place over several days in May and June. In 2013 approximately 4916 individual plants were chemically treated on the Medway. In 2014 the number of plants recorded and treated was approximately Giant Hogweed abundance on the Medway (especially the navigational section) has greatly reduced from that of pre project years. Maps of the 2013 treatment year are available upon request for comparison, however Map 3 below shows Giant Hogweed on the upper Medway in 2014 (please note Giant Hogweed also occurs around Buckhurst which is not plotted on this map) and Maps 4 and 5 (page 10) highlight the lower sections of the Medway in The colour codes on the maps indicate the approx. stand size/ number of plants for that given GPS reading. Map 3 (pg. 10) highlights a large stand near Penshurst and Map 4 (page 10) shows a large area near Aylesford and some larger patches around Wateringbury and East Farleigh. However, although Giant Hogweed still occurs, most of the original larger stand locations have been reduced to areas of only one or two plants and the Medway is considered to be greatly improved from that of previous years. Map 3 showing treated Giant Hogweed locations in the Upper Medway in 2014 MVCP 9

10 Map 4 showing Giant Hogweed location on the Medway around Tonbridge in 2014 Map 5 showing Giant Hogweed locations on the lower Medway towards Maidstone and Aylesford in

11 In 2014 MVCP also carried out a survey of the lower tidal section of the Medway known as the Medway Gap. At present the project ends it s operation at Aylesford but reports of Giant Hogweed were received for this lower stretch, initiating MVCP s July survey. Below is a map of the Giant Hogweed survey of the tidal section. Plant occurrence was infrequent but where Giant Hogweed did occur, large stands of potentially plants in a given location were observed. Unlike the other plants indicated on maps in this report, no treatment was undertaken of this location. Additional funding will be required to incorporate this location and support staff time to research and communicate with new landowners. MVCP hope to arrange this by 2015 but at the time of report writing (September 2014) no funding or plans are concrete. Map 6 - showing Giant Hogweed (and one stand of Japanese knotweed) in the Medway Gap July 2014 MVCP Below Photo showing one (dying back) Giant Hogweed stand in the Medway Gap in 2014 MVCP 11

12 In addition to Giant Hogweed control, Pennywort on the Medway since MVCP have been tackling the issue of Floating Data for distribution and abundance in 2014 is currently being compiled as treatment is ongoing at the time of report writing. However, Map 6 below highlights the areas of Floating Pennywort in All the areas on the map were treated by MVCP in To date in 2014 Floating Pennywort has been observed in the marinas and treatments will be repeated in these locations. No Floating Pennywort has been observed in the Medway but MVCP will survey the section of Medway highlighted in Map 7 below and check for Floating Pennywort as standard. This will take place in October 2014 at the same time as doing repeat treatments at the source location (see below) and in the marinas. Map 7 Areas of Floating Pennywort on the River Medway treated in 2013 MVCP MVCP have been liaising with a local landowner to treat what is considered to be the source of the Floating Pennywort problem (a private pond near the Medway). In partnership with the Environment Agency who have helped improve and maintain access to the pond, MVCP s contractor has carried out regular chemical sprays of the Floating Pennywort. 12

13 In addition to Floating Pennywort at the source pond, MVCP s contractor noticed the presence of Water Fern. Water Fern is best controlled via the America Weevil as a bio-control method. As such, MVCP arranged to purchase and release these weevils to act as the control vector for the Water Fern present. However, upon a repeat visit, the Water Fern was no longer observed, possibly reduced and/or eliminated by a naturally occurring weevil population. However it is possible that the plant will be found on site again and so MVCP will continue to watch for it in this location. Although it is unlikely that Water Fern would establish in the Medway (the species prefers slow flow or still waters) it is important that it is treated in this adjacent pond in order to safeguard important local side streams. The photograph below shows the source pond in question. In this photograph both Floating Pennywort and Water Fern can be seen in the body of the pond itself. On the banks Himalayan balsam is observable. Himalayan balsam, Floating Pennywort and Water Fern at a pond adjacent to the Medway 2014 Brian Thomas (MVCP) Some areas of Himalayan balsam have been removed near the Medway by MVCP s volunteers in Specifically at Yalding Fen, adjacent to the Medway, several task days have involved the removal of Balsam. A task day for Tonbridge and Malling Borough Council also involved removing Balsam (and some Giant Hogweed) from Tinkers Island on the Medway. MVCP s contractor also treats Japanese knotweed around the Penshurst Estate and for some landowners on Wateringbury Mill Stream. 13

14 4.2 The River Beult The Giant Hogweed only appears on the lower stretch of the river below the confluence of the Lesser Teise. In 2013 Giant Hogweed plants on the River Beult were treated in May and June and 1049 plants were recorded and treated. In 2014, 230 plants were recorded and treated on the Beult. The figure of the number of plants is taken from observations at the time of surveying and so is unlikely to be 100% accurate. However, it is considered to be reasonably accurate, especially in a location where plants are not that abundant. Although these counts are approximate they highlight that Giant Hogweed is reducing in it s abundance on the Beult due to ongoing annual treatment works. Maps of the 2013 treatment year are available upon request but Map 8 (pg. 15) highlights the Giant Hogweed on the Beult, Teise and Lesser Teise together in Note that Giant Hogweed on the Beult occurs only below the confluence with the Lesser Teise. More work is required to continue to see River Beult improvements and especially to safeguard the Beult from an abundance of Giant Hogweed which occurs in the River Teise and thus the Lesser Teise. Some landowner involvement gaps are present on the Teise which also need addressing. In addition, upstream of the Teise confluence there have been reports in the past of Japanese knotweed (treated by MVCP in 2012) and Water Fern. Water Fern surveys in late 2013 indicated that the species had possibly been washed out of the system, however more surveying should be scheduled for the future to ensure this species does not cause problems for the Beult. Himalayan balsam occurs upstream of the Teise confluence in small amounts and it is known to be present on some of the Beult tributaries such as Hammer Stream. Although unlikely due to access issues, funding and treatment restrictions, MVCP would like to be able to assist landowners to remove/treat this balsam and reverse a potential problem for the Beult. A site visit with a local landowner in scheduled for October The Greater and Lesser Teise In 2013 the Teise was treated for Giant Hogweed in May and June and the number of Giant Hogweed plants recorded and treated was approximately 10,517 In 2014 the Teise was treated for Giant Hogweed in May and the number of plants recorded was approximately 2,732. The Lesser Teise was treated in May in 2013 with a Giant Hogweed plant count of approximately In 2014 the Lesser Teise was treated in May and June with an approximate count of 707 plants. Again, although these figures are approximate, the difference in the count indicates a significant reduction thanks to annual control maps are available upon request but Map 8 (pg. 15) highlights the Giant Hogweed on the Beult, Teise and Lesser Teise together in

15 Map 8 showing Giant Hogweed on the Beult, Teise and Lesser Teise in 2014 MVCP Map 8 above highlights that across the Teise and Lesser Teise Giant Hogweed is still very frequent in its distribution and abundance. Fortunately however the number of plants overall does appear to be falling, as indicated by the actual number of plants counted and treated each year (down by approximately plants between 2013 and 2014). Larger stands are observable specifically around Laddingford and Collier Street locations and it is clear that ongoing treatment work is essential to keep reducing the seed bank, along with bridging any landowner knowledge and involvement gaps. 15

16 MVCP became aware of a significant increase in Japanese knotweed in especially on the River Teise. Additional funds from the Environment Agency were allocated to the task of tackling this increase in Japanese knotweed on the Teise, which appeared to be the area most effective. Treatment of the Teise also helps to safeguard the River Beult (part of which is a Site of Special Scientific Interest SSSI) and also the main Medway below Yalding. Detailed maps of each section of the Teise are available but Map 9 opposite shows an overview of the Japanese knotweed locations on the Teise in Map 9 showing Japanese knotweed stands on the Teise in 2014 MVCP Chemical treatment of all these Japanese knotweed stands have just been completed by MVCP (Sept 2014). 16

17 4.4 Gibbs Brook Gibbs Brook is a tributary of the River Eden which in turn is a tributary of the Medway. Gibbs Brook has had a significant Giant Hogweed problem in the past and has been treated by MVCP for many years. In 2013 plants were treated in April and the number of Giant Hogweed plants was counted at approximately 1,279. In 2014 Gibbs Brook was treated in March and April and the count again was for 1,279 plants! This indicates that the counts are accurate and that at Gibbs Brook there was no reduction of plants over the last few years. However, looking back at older data, in 2012 the count was for approximately 3000 plants so plants do appear to be reducing slowly. Part of the issue at Gibbs Brook is a large Southern Water site which MVCP do not include. Southern Water use their own contractors. Communication between MVCP and Southern Water in 2014 indicated that they had recently improved their management plan and were planning to increase their treatment of Giant Hogweed and aim for an elimination of it at their site. This partnership working is essential and the increased focus and work at this site will dramatically improve the prospects of the area. A map of Gibbs Brook and the location of Giant Hogweed plants is available upon request (not included as standard due to low quality). 17

18 4.5 The River Cray: Giant Hogweed treatment on the River Cray used to be covered by North West Kent Countryside Partnership (NWKCP) but was incorporated into the MVCP scheme in Some landowners in this location carry out their own control of Giant Hogweed and because there are some large private firms and industrial estates many have their own contractors. MVCP attempt to speak to as many local companies as possible to check their commitment to plant control. Large areas of land belonging to the London Borough of Bexley and to companies such as Bexley Sand and Ballast are included in the MVCP spray schedule. In 2014 MVCP checked an additional footpath for Bexley Council and also added additional areas of land belonging to the Dartfordians Community and Sports Club. Giant hogweed was treated along the River Cray in 2013 in May and the plant count was 242. In 2014 plants were treated in April and the plant count was 2,124. The increase in plants will be due to an increase in the land covered this year. Maps of 2013 are available upon request but below is a map showing the locations and abundance of Giant Hogweed along the Cray in Additionally in 2014, MVCP s contractor will be returning to the area in September/October to treat areas of Japanese knotweed for a few local landowners. We have also given advice about Floating Pennywort on land close to the Cray tributary the Shuttle and our contractor has worked privately to address the Floating Pennywort at this site. This is something MVCP will be monitoring in future. Map 10 Giant Hogweed locations on the River Cray in 2014 MVCP 18

19 Our sister company North West Kent Countryside Partnership (NWKCP) manage a variety of conservation and biodiversity projects on the River Cray and the surrounding areas and whilst MVCP have been looking at Giant Hogweed, Japanese knotweed and Floating Pennywort, NWKCP have carried out tasks which have included Himalayan balsam control adjacent to the Cray. Balsam removal has been ongoing by NWKCP at Hall Place Recreational Ground for a number of years but staff had concerns that removal of the balsam was reducing the amount of cover that was available for resident water voles. Since the area is heavily used by dogs, cover for water voles is a high priority. In order to address both the balsam and the issue of habitat cover for the water voles, in 2014 NWKCP and their volunteers pulled the balsam at the rivers edge and then planting native marginal aquatic species in it`s place. This seems to have worked for now but next year of course the remaining balsam seed will germinate and try to out complete the natives that have been planted, so repeat manual removal of the Balsam will continue. There is some evidence to suggest that planting native marginal vegetation post invasive species removal reduces the risk of further infestation of an invasive species, as the ground is not bare. It will be interesting therefore to monitor this site into the future. This project involved further use of volunteers, as evidenced by the photograph below. Volunteers preparing native marginal plug plants for planting post Himalayan balsam removal at Hall Place Recreational Ground adjacent to the River Cray in 2014 North West Kent Countryside Partnership 19

20 5. Overview - Awareness raising, training, communication and volunteers: Two newsletters about the project and national Invasive Non Native Species (INNS) news were written and distributed to landowners, relevant organisations and project partners in 2014 Three Volunteer Task days were carried out by MVCP in both 2013 and 2014 to remove areas of Himalayan Balsam and raise awareness of INNS. A training event on Invasive Flora and Marine Invasive species was carried out for local professionals and volunteers in Spring MVCP and MSEP volunteers have collectively done over 300 volunteer hours assisting with INNS projects in NWKCP volunteers have also done additional hours with balsam removal and native plug planting near the River Cray. In Spring 2014 MVCP staff gave a lecture to Hadlow College students about Invasive Non Native Species Issues MVCP have agreed to deliver a Kent Wildlife Trust Training Day on Invasive Species in May Several private landowners have had advice from MVCP about Japanese knotweed control in their gardens in many in the Tonbridge and Malling district. A conference in London on the CABI Himalayan Balsam Bio-Control Project was attended by MVCP staff in June In partnership, MVCP and CABI have planned to deliver the CABI Himalayan Balsam Bio-Control Project conference to interested professionals and project volunteers in Kent in October (Above) MVCP s Giant Hogweed and Invasive Plant Project Newsletter covers for Spring and Autumn 2014 MVCP 20

21 6. Future requirements: It is essential that the Giant Hogweed and Invasive Plant Project in the Medway Catchment and River Cray continue into the foreseeable future. It is clear from plant count data and observations that plant abundance is reducing over time, but the seeds are viable in the soil for a number of years and thus the seed bank for Giant Hogweed is extensive and so control takes time. Also, a few untreated plants in the catchment will impact on success so, although landowners remain responsible for control overall, a central organisation of the project is required to ensure as much work is being done on a catchment scale as possible. Working in this way also ensures that other high priority species can be observed and managed before additional long term problems develop, such as with MVCP s work with Floating Pennywort. The local understanding that MVCP lead on invasive flora control also aids landowners in seeking advice and allows other organisations to ask for training and resources. In addition, MVCP can link in with the Non Native Species Secretariat (NNSS) and keep government up to date better via leading on a catchment wide campaign. In addition to the continuation of the standard project as outlined in this report, MVCP would also like to find additional funding to: Extend the project into the Medway Gap (see page 11). Work with CABI to establish an area on the Medway for Himalayan Balsam Bio-Control in 2015 and onwards to begin reducing this invasive species across the catchment (no plans as yet but MVCP in touch with CABI and interest expressed). Assist landowners on Hammer Stream (tributary of the Beult) with Himalayan balsam control Continue to survey for and monitor Water Fern and implement treatment where required Continue to treat and ideally eliminate Floating Pennywort from the system Survey and implement any required treatment of Giant Hogweed on the River Darent: Observations and recordings of Giant Hogweed on the River Darent were passed to NWK and MVCP in These are new records and so MVCP would like to investigate further and ideally eliminate any Giant Hogweed on the River Darent before the plant species causes long term control issues. In 2015 MVCP staff plan to survey the river with NWKCP colleagues. In the meantime (via the Autumn newsletter) local landowners are being asked to get in touch with information on any plants observed. Ideally additional funding is required to support staff time in researching and communicating with landowners about this important topic in this (new for the project) location. Ongoing Invasive Flora control is important in the Medway Catchment (and nearby water bodies) to safeguard and improve the biodiversity of our rivers, reduce flood risk, support access for river recreation, support farmers and reduce future control costs and health and safety issues. Invasive species control is an important topic nationally and MVCP s experience in this field within the Medway Catchment should continue to be supported into the foreseeable future. 21

22 7. Project finances: Information on the projects finances is available upon request. 8. Contact Information: For information on Medway Valley Countryside Partnership please refer to our website: or contact the office on For more information on the Giant Hogweed and Invasive Plant Project please contact Andrea Griffiths (BSc Hons) via or by calling Medway Valley Countryside Partnership 3 Lock Cottages Lock Lane Sandling Kent ME14 3AU medwayvalley.org For information generally on different invasive species and national strategies either contact MVCP or visit the Non Native Species Secretariat website on 22