- Research Highlights -

• RBGE's work on lichens contributes innovative research towards the protection of Scotland's native biodiversity, and towards our wider obligations to protect global biodiversity. Our work reflects the international (European) importance of British lichens, by using native species and habitats to address questions of wide scientific importance and general relevance.

• Below is a summary of individual outputs (post-2000) which highlights our collective research on lichens.

• How best to manage habitats to protect biodiversity in the face of climate change is one of conservation's most pressing challenges. Answers may gained by examining current distribution patterns. An intriguing observation in the biogeography of Scottish lichens is the extent to which certain species use habitats of different quality in contrasting climates. In particular, a number of ‘oceanic’ species (e.g. Degelia atlantica, Lobaria pulmonaria) are common in western Scotland on various tree species, on trees of mixed age, and in woodlands with different levels of continuity. However, along a transect towards a sub-optimal (drier) climate in eastern Scotland, the same species become increasingly restricted to specific habitats, e.g. preferentially growing on certain tree species (notably rowan, and aspen), on older trees, and in old-growth woodlands.

• Characterising the changing habitat specificity of lichen epiphytes in contrasting climates provides a potentially powerful management model, in which local habitat may be manipulated to off-set the projected impact of climate change. Thus, we combined different datasets in a biogeographic analysis: (i) confirmed lichen presence/absence, compared to (ii) site-specific measures of old-growth woodland extent, and (iii) macroclimatic data. We were able therefore to identify a suite of lichen indicators, which responded to the combined effects of old-growth woodland extent and climatic setting. The response of these species (proportion of Scottish sites occupied) was compared to change (increase or decrease) in old-growth woodland extent, under contrasting climate change scenarios. We can thus tentatively estimate the degree of woodland increase required around old-growth remnants in order to off-set the negative impacts of climate change.

• Ellis, C.J., Yahr, R. & Coppins, B.J. Local extent of old-growth woodland modifies epiphyte response to climate change. Journal of Biogeography, in press.

• Standard texts on the history of the British vegetation delimit a range of dominant forest-types: e.g. Oak-Elm-Birch wood in north-west Britain, and Pinewood in central-northern Scotland. These forest-types resulted from vegetation succession following the last ice age, and existed during the period in which human modification became the dominant force shaping our vegetation (ca 5000 yr BP). Hazel coppice is an important semi-natural woodland-type resulting from the amalgam of natural and human influences, and is a celebrated habitat of conservation concern. The effect of selective coppicing is widely believed to have been a principal driving force in creating hazel-dominated woodland in Britain.

• However, evidence using lichen indicators of ecological continuity (see below) has pointed to the existence of a hazelwood maintained in the absence of coppice management. In this case hazel has maintained its dominant role in the canopy over long-periods of time, resulting in the development of a unique lichen flora which is characteristic of natural hazelwood. The flora far exceeds that of coppice hazelwood in terms of biodiversity and conservation interest. Hazelwood and its epiphyte flora is typical of hyper-oceanic western Scotland, and is maintained by the extreme longevity and growth dynamics of individual hazel stools. Lichen indices have thus been used to challenge the role of intensive management as the exclusive force maintaining hazelwood in Britain.

• Coppins, A.M. & Coppins, B.J. (2003). Atlantic hazelwoods – a neglected habitat? Botanical Journal of Scotland, 55: 149–160.
• Coppins, A.M. & Coppins, B.J. (2002) Scottish Atlantic hazelwoods: some observations on the ecology of this neglected habitat from a lichenological perspective. Scottish Woodland History Discussion Group Notes, 6: 1–6.
• Coppins, A.M., Coppins, B.J. & Quelch, P.R. (2002). Atlantic Hazelwoods: some observations on the ecology of this neglected habitat from a lichenological perspective. British Wildlife, 14: 17–26.

• Lichens are traditionally less well recorded than vascular plants, and especially for certain difficult taxa, species distributions are likely to be incomplete. The use of hectads in assessing conservation status is therefore dubious. Certain common but obscure species may be over-looked, while certain species may be rare not because of a human-induced decline in their population, but because they exist in Britain at a natural range boundary. Assessment of conservation status depends therefore on the synthesis of data and expert editorial opinion.

• While IUCN assessment is currently the highest standard in conservation, our knowledge of the British lichen flora continues to change rapidly. Maintaining an authoritative source of up-to-date information on conservation status is therefore a challenge. Accordingly, this new checklist provides full IUCN assessment for 1850 lichen taxa in the British Isles, with 208 species placed onto the main list. Taxa which have been added or re-evaluated since the 1997 Red Data Book are annotated, with notes as to their status.

• Woods, R.G. & Coppins, B.J. (2003) A Conservation Evaluation of British Lichens. British Lichen Society, London.

• In 1974 Francis Rose proposed an index by which lichen epiphytes could be used to infer the ecological continuity of a woodland habitat. Unlike vascular plant indicators, which have a seed-bank and may thus survive ephemeral woodland clearance and replanting onto an ancient woodland site, epiphytes are entirely dependent upon the presence of trees, and are therefore sensitive indicators of continuous tree-cover. Such indicator lichens are typically micro-habitat specialists, or dispersal-limited, such that their likelihood of occurrence increases with the age of the woodland.

• Based on extensive field observations and notes on woodland history a suite of new Indices of Ecological Continuity present a semi-quantitative framework for assessing woodland continuity, and, by extension, the relative conservation importance of a woodland site. This work extends the use of indices across the British Isles, and explicitly recognises the climatic limits to ecological indicators, proposing different index-species in contrasting climatic regions. These new Indices provide a general and standardised base-line assessment for field surveyors, and an important example of the practical use of lichens as bioindicators.

• Coppins, A.M. & Coppins, B.J. (2002) Indices of Ecological Continuity for Woodland Epiphytic Lichen Habitats in the British Isles. British Lichen Society, London.

• A stable taxonomy and a comprehensive list of extant species are pre-requisites to effective conservation. They are the tools which enable application of a standardised and consistent nomeclature during recording. This ensures data quality when species are used in biogeographic or ecological research to ask questions about the pattern and processes controlling diversity.

• In terms of natural history, the British Isles are one of the best studied regions of the world. Nevertheless, for many groups of organisms there remains much basic work to be done in describing new species and sorting out problems to provide a clear and uncomplicated taxonomy (e.g. without synonymy). Until relatively recently, lichens have been one of the groups whose British species were incompletely described.

• The publication of a new Checklist for British Lichens is a major contribution toward conservation and biodiversity science. While new species will continue to be added to the British lichen flora, and notwithstanding issues of synonymy which may require molecular tools for determination, the Checklist (and its web-based up-dates) testifies to a rapid advance in British lichen taxonomy during the last three decades. It provides the standardisation necessary to effective conservation, and is a milestone in British biodiversity research.

• Coppins, B.J. (2002) Checklist of Lichens of Great Britain and Ireland. British Lichen Society, London.