There have been several mistletoe survey projects within the UK in the last few decades. The biggest was the National Mistletoe Survey of the 1990s, updating a previous national survey from the 1970s. The 1990s survey was a joint BSBI/Plantlife project instigated and co-ordinated by Jonathan Briggs. Other more local and regional surveys have taken place since, most simply gathering data on distribution and hosts.
In the winter of 2011/12 Mistletoe Matters launched a new national project looking at a range of practical issues – management practices and specific information on susceptibility of fruit tree varieties. That multi-purpose project, launched as the Mistletoe League Project will continue gathering information for some time yet. The project is now split, for reasons of clarity, into smaller component projects.
Details of some of these survey projects are given below – scroll down or use the index links below for more information.
The Mistletoe League Project is a suite of surveys looking at specific aspects of mistletoe, mainly its behaviour and management on fruit trees. The project was launched by Mistletoe Matters in the winter of 2011/12 and is slowly gathering data over several years.
The project is primarily about fruit trees in orchards and gardens rather than mistletoe in the wider environment and on other host trees.
Anyone can take part – we are particularly interested in recording people’s experience of managing mistletoe on fruit trees in both orchards and gardens and on recording which fruit tree varieties (mainly apple varieties) are most and least susceptible to mistletoe. The aim of that last aspect is to compile a league table of which apple (and other fruit) varieties are most likely to be suitable for mistletoe and which are the most resistant.
The three main elements are the survey are outlined below, with links to more information and the survey forms:
Not got fruit trees? Seen mistletoe and want to record it? Details of a general recording scheme will be posted here soon.
Over the winter of 2010/11 Mistletoe Matters ran a survey collecting information on where people get their Christmas mistletoe, and how they use it.
Raw results are available, in pdf format, by clicking here or in the image above. Note that this is raw data in the form of bar-charts generated by SurveyPirate.
Many regional, county-based and other local mistletoe surveys have been organised since the 1990s National Survey. Examples include surveys organised by county Wildlife Trusts (e.g. Norfolk, Herefordshire etc) and surveys of particular mistletoe populations outside of the main mistletoe areas (e.g. studies in Richmond, Essex, Cambridge and Dublin).
Some of these local studies have produced interesting and intriguing results, suggesting that mistletoe is spreading faster than usual in some relatively isolated eastern mistletoe colonies (particularly in Richmond, Essex and Cambridge). These results may simply be reflecting a natural increase in spread as mistletoe berry numbers increase (each plant produces double the number of flowers, and thereforedouble the berries each year, so accelerating spread might be normal) but, as some of these populations are already over a century old and have not shown this behaviour before, it may be that other factors are responsible.
One possibility is climate change - modelling using mistletoe's climatic preferences suggests that it will spread eastwards in Britain and northeast-wards in mainland Europe with expected climate change. So this could explain new spread in the east. An alternative and/or additional explanation is a change in bird vectors, which may themselves be due to climate change. Overwintering Blackcaps, which are very efficient mistletoe spreaders, have increased from a handful to many thousands in Britain in recent decades, and these birds may well be affecting mistletoe spread. More details on some of these issues are available in our Information Sheets.
We are not aware of any local mistletoe survey projects at the moment but will add details and links here when these occur. If you are running or aware of a local mistletoe project do let us know - our contact details are here.
Much of what we know about mistletoe distribution in the UK comes from survey work by the Botanical Society of the British & Ireland (BSBI) in the 1970s and a follow-up project, jointly run by BSBI and Plantlife in the 1990s. The latter survey was coordinated by Jonathan Briggs.
The peculiar pattern of mistletoe across the country is immediately visible by mapping the survey results, shown in the picture above. Most of Britain's mistletoe is clearly concentrated in the south-west midlands, specifically the counties of Herefordshire, Monmouthshire, Worcestershire, Gloucestershire and Somerset. Apple trees came top in the survey as the favourite host tree, and gardens and orchards came top for habitat. The graphs below summarise the overall host and habitat data from the 1990s survey.
It was that preference for apple trees that initially prompted the 1990s survey - was the decline in traditional apple orchards, a traditional landscape feature of mistletoes SW midlands homeland, causing a similar decline in mistletoe?
Results, as you can see from the maps above, were not very conclusive. In distribution terms the pattern was very similar to the 1970s, with an apparent increased distribution in the east of Britain. But that distribution data hides information on quantity which, according to the views expressed in the survey, was changing with apple orchard loss. It would seem that mistletoe itself is not threatened and might even be thriving, but the Christmas harvest, from traditional apple orchards, might be endangered. The survey results were described in a joint BSBI/Plantlife report Kissing Goodbye to Mistletoe? written by Jonathan Briggs in 1999.
That report is, of course, not the end of the story. Why were there more records in the 1990s - was there better recording than in the 1970s or was there really more mistletoe in some areas? And is the mistletoe harvest from old orchards really threatened - in many orchards in mistletoe's main stronghold there seems to be even more than there used to be. But mostly only in very neglected orchards - which would suggest this is not a sustainable situation.
Those two key questions - about distribution change and about quantity available in orchards - are still unanswered but there is some information to work on. Some comes from the regional and local mistletoe survey projects mentioned above. These support the idea of distributional change, possibly linked directly or indirectly to climate change. As for the available crop from orchards, that continues to be a concern, and is one of the issues the Mistletoe League Surveys (details above) are currently investigating.
For more information on all these issues visit our Information Sheets page where there are downloadable summaries on distribution, rarity and management/supply and links to some recent publications reviewing the issues.