A new long-term survey to measure the impacts of ash dieback on the flora of British woodlands

The ongoing development of a new plant surveillance and monitoring scheme for seminatural habitats (Walker et al., 2010) has coincided with the arrival of the fungal disease ‘ash dieback’ in Britain. This is caused by Hymenoscyphus pseudoalbidus, the sexual (‘teleomorphic’) stage of the ash dieback fungus. The perhaps better known name Chalara fraxinea applies to the asexual (‘anamorphic’) stage, now thought to be less epidemiologically significant (Sansford, 2013). The arrival of ash dieback on our shores has created an unprecedented opportunity to monitor the impacts that the spread of a fungal pathogen might have on woodland ecosystems. Research in Sweden has already suggested that the loss of epiphytic lichen communities associated with ash could be severe (Jonsson & Thor, 2012), but to our knowledge no European country has yet implemented a nationwide programme to monitor systematically the changes to communities that might occur as a result of this disease. Furthermore, even at a global level the information on the consequences of the loss of tree species on associated organisms is scarce (Ellison et al., 2005). To this end, the BSBI and other volunteer societies (the British Bryological Society and the British Lichen Society) have been working with the Centre for Ecology and Hydrology to develop a survey method to identify the longterm impacts of ash dieback on the ground flora and epiphytes associated with ash trees in woodlands. By monitoring plots both in stands of ash and stands of other broad-leaved species, we hope to measure the impacts of the disease, whilst controlling for changes that may be due to other drivers, such as climate and management. The British Bryological Society and the British Lichen Society are to focus on epiphytic bryophytes and lichens growing on ash in woodland and in open habitats, such as parkland and hedgerows. We are aiming to launch the scheme in 2014 with plots being revisited as part of an ongoing five-yearly programme of monitoring. We hope that this note will encourage people to leave a couple of free days in their field calendars to enable them to participate. The survey comprises a minimum of two field visits to a single monad or adjoining areas, although visits to multiple monads are possible. The project website is still undergoing development (ash-related photographic contributions are welcome), but several key documents, including a project overview, specific instructions for the vascular plant survey, and a recording form, are already available for download (see http://www.brc.ac.uk/splash). A list and accompanying map of ‘core’ monads that we aim to survey is also available. If you are interested in taking part monads can be reserved now by emailing: ashsurvey@ceh.ac.uk. Additional monads selected by surveyors can also be contributed to the project, so do not despair if the core monads near you appear to have already been taken. We hope that this survey will be an important step towards quantifying the effects of ash dieback on the biodiversity of British woodlands, and we look forward to working with all members who are keen to take part in this project.