Pioneering Work at Ladywalk on Himalayan BalsamThere is an old notice in one of the hides at Ladywalk which states “Stop the AlienInvasion. Please help eradicate the Himalayan Balsam which has invaded parts ofthe reserve”. But rather like the line “Don’t Look Ethel, It’s Too Late” from the RayStevens song, The Streak, it is too late at Ladywalk to halt the Himalayan Balsam.The reserve is in danger of becoming the West Midlands capital of Himalayan Balsam as there are large areas of the plant, in effect a monoculture, with plants that can grow to over three metres crowding out all other plants. They are shallow rooted and when they die in winter they expose large areas of barren land that is easily eroded. Attempts by various working parties to pull and the kill the plants over recent years have only been partly successful. We have worked hard at pulling the plants by hand and have been able to control large flat areas inhabited by the plants with the flail mower but there are other areas too inaccessible and damp for us to become involved.But in 2017 Ladywalk and Kingsbury Water Park have become sites of pioneering work initiated by Tame Valley Wetlands Partnership (TVWP), working closely with the Centre for Agricultural and Bioscience International (CABI). As you may have seen on Gardeners’ World in September this entails the release of rust spores, which act as abiological control agent, on to the Himalayan Balsam plants. First results of these releases are promising!There has been close contact with scientists from CABI who have instructed us where and how to apply the rust spores which should be done in the evening on three occasions during the growing season. Where to treat plants is a key issue. There needs to be a high density of plants, so Ladywalk wins there, near water and where humidity can be high. But the spores must be released in an area which will not be submerged by floodwater for long periods.The rust spores, which are very expensive with storage arrangements having to bemanaged very carefully, are mixed with water and the plants’ lower leaves are thensprayed with a hand sprayer. The inoculated plants are observed for four weeks for the development of rust on the lower leaves. As the plants die at the end of the year the rust enters the leaf litter in winter and reappears in the new plants the following spring, manifested as infections in the new stems. This leads to plants having a stunted growth with less height. The rust can also be spread through the air so it is hoped that it will spread further afield and infect plants over greater distances.CABI remain very involved in monitoring progress and supplying the rust spores. They have overseen this experimental work in 33 selected sites across the UK and prior to the site work had to acquire a license from Natural England and European Botanical Agencies. The necessary permissions for our pioneering work were also successfully secured from Eon, owners of the Ladywalk land, and the WMBC executive. The main question at the Executive meeting was the effect that this work would have on bees. Bees appear to love the nectar of these plants but we were informed that the rust fungus will not lead to the total eradication of the Himalayan Balsam but a reduction in the number and density of these plants. This means that native plants will return enabling bees to cross pollinate them rather than operating in a Himalayan Balsam “monoculture”.The original releases nationwide of the rust fungus were strictly controlled withHimalayan Balsam plants being grown independently and inoculated with the rust fungus before being “planted” in areas of high Himalayan Balsam density that met the environmental criteria for such experiments. These rust releases over the last two years have aided knowledge on when best to administer the rust, in previous years they were first done in May when temperatures were too low. Additionally we needed to release the correct rust as Himalayan Balsam has a wide range in the Himalayas – there are Indian and Pakistani populations requiring different rust strains! So before any releases seeds from the Ladywalk’s plants had to be collected, sent to CABI and analysed. So Ladywalk and the WMBC are benefitting from the work done elsewhere by the CABI scientists. The rust fungus is in place and first impressions are that it is having an effect.Next year we will see the real benefits of our releases and we hope to see areas where there is a lower density of plants. It will be interesting to see how the effects will spread across the reserve, even downstream. We will keep you informed!We are grateful to Tracey Doherty and colleagues from Tame Valley Wetlands Partnership for identifying Ladywalk as a test area, and for the associated funding, as well as the scientists from CABI for their continuing input.
Ratty’s Return (Excerpt from Tame Valley Wetlands Website)
As part of our ‘Ratty’s Return’ project, Tame Valley Wetlands have been working with our partners to get the area ready for the return of ‘Ratty’ the water vole. During May 2017 we have carried out two areas of bank improvements at strategic sites where water voles were once found.
Ladywalk Nature Reserve – 175m of bank improvements
Working with West Midland Bird Club, we have started work on an area where water voles used to be found. The ditch line runs 600m north south through the reserve. Working together in partnership, we have focused on a 175m stretch of ditch. Volunteers from West Midland Bird Club and our Tameforce volunteers spent three days transforming a Himalayan balsam jungle into an area which will again provide habitat for this cute mammal. Firstly, the Himalayan balsam was strimmed and pulled out to prevent it from growing. This non-native species can dominate a landscape, making it hard for our native plant species to survive. Native plant species are an essential food source for water voles and provide important cover for their burrow entrance.
We then used pre-planted coir pallets (filled with Ratty’s favourite food plants) to line and stabilise some of the ditch banks. Where the banks were too steep, we planted marginal plug plants including purple loosestrife, flag iris, water mint, water forget-me-knot, grasses and sedges. Steep slopes are good for water voles to burrow into but it is important to get good vegetation cover to hide their entrances.