RBGE scientists are actively involved in primary research and training across academic levels. Here, we provide summaries of recent research projects (since 2005), in addition to more formal reports on specific projects:

Conservation of Vulpicida pinastri (2006-2007)
Aspen Epiphyte Project (2003-2006)

2011 - Lichen Diversity on Scottish Aspen: A Component of the Extended Phenotype
by Chantel Davies (PhD - Biology)

Aspen forms discrete genetic clones within Scotland's native woodlands - epiphyte communities vary among these clones. Aspen was used as a model system to test the effect of phenotypic differences - under genetic control - on the community structure of lichen and bryophyte epiphytes. Analysis of the aspen phenotype was targeted to bark secondary compounds, and physical structure (roughness). Studies in natural woodlands were accompanied by long-term field trials, in which samples from contrasting aspen clones were grown in a randomised block design. The results from both natural woodlands and field trials, demonstrated an important effect of genetics of the foundation species (aspen) on the range of dependent epiphytes, especially through clonal variation in bark texture.

2011 - Testing Species Concepts in Red-fruited Pyxie-cup lichens: A study within the Cladonia coccifera group
by Catherine Kwella (BSc - Plant Science)

Species concepts within the Cladonia coccifera (Ascomycetes, Lecanorales) complex were tested using an approach that integrates morphological, chemical and molecular data from a range of specimens of C. coccifera, C. diversa and C. borealis. A suite of morphological characters were measured and included in a multivariate analysis alongside data on the secondary chemistry of the specimens. Sequences from the ITS 1 and 2 regions of nuclear ribosomal DNA were used to construct a phylogeny of the species in question, and compare genetic with phenotypic similarity. The results provided little evidence for C. coccifera and C. diversa being morphologically distinct groups and many of the phenotypic differences between them could be accounted for by ecological differences associated with altitude. The molecular data do not support the monophyly of any of the three species, although it is possible that multiple copies of ITS were sequenced. Genetic similarity between specimens does not track phenotypic similarity, providing further evidence for the morphological and chemical characters in this group being environmentally determined.

2010 - Life on the Deadwood: Patterns of Lichen and Bryophyte Community Structure on Stumps in a Caledonian pine forest
by Verena Blasy (MSc - Biodiversity and Taxonomy of Plants)

Deadwood is considered a key structural component of 'old-growth' forest, while deadwood volumes in British woodlands tend to be relatively low. The managed forest system produces unusual deadwood structure, such as cut-stumps. This project investigated the community composition and richness of cut-stumps across a range of field-settings, e.g. open-, gladed- or closed-canopy stands, looking also at contrasting cutting techniques (height of stump). Using Abernethy forest as a study system, it explored the interaction between mechanised tree-felling, and conservation actions aimed at recreating 'old-growth' structure. The results demonstrate a successional sequence of lichens, bryophytes and vascular plants, during production to the final decay of stumps, the controlling effect of the local environment on this successional sequence, and the potential importance of cut-stumps as a resource for rare species.

2010 - Testing the Hypothesis of Climatic Equilibrium: Lichens in Britain and North America
by David Braidwood (MSc - Biodiversity and Taxonomy of Plants)

Bioclimatic models are used to assess the 'exposure' of species to future climate change scenarios. They are correlative tools, predicated on the assumption that species are adapted to different climatic settings, and respond directly to macroclimatic change. This is an appealing assumption, but is challenged by, for example, neutral theory; it is also brought into question by niche-related theories, which demonstrate the non-equilibrium of species with climate, dependent on historical contingency, or which highlight smaller-scale effects (such as species interactions) which may also control distributions. This study aimed to test the fundamental assumption of climatic equilibrium. It compared the distribution of lichen species in Britain and North America, asking whether the species distributions - independently derived on two separate continental regions - are comparable. If distributions match across species, this would provide evidence of climatic equilibrium. The results showed that in a majority of cases bioclimatic distributions did match among species, suggesting an effective tracking of climate space during the post-glacial - but that important exceptions also occur.

2008-2010 - The Accumulation of Epiphyte Diversity in Scotland's Atlantic Oakwoods
by Dr Joe Hope (Post-doctoral Research Fellow)

Using Scotland's Atlantic oakwoods as a study system, this project field sampled lichen epiphytes for carefully delimited stands of known age: comparing recently regenerated stands (< 100 yr old), with 'old-growth' stands (> 250 yr old). Epiphyte species composition and richness were compared to stand age, landscape-scale connectivity, tree age, and tree size, and edaphic factors, to determine limits in community development. Establishing these controls was used to provide recommendations for native woodland regeneration strategy. The project was funded by Scottish Natural Heritage.

Ellis, C.J. & Hope, J.C.E. (2011) Lichen Epiphyte Dynamics in Scottish Atlantic Oakwoods: the effect of tree age and historical continuity. SNH Commissioned Report No. 426.

2007-2010 - Biodiversity Loss across the Threshold of Industrialisation
by Dr Rebecca Yahr (Leverhulme Research Fellow)

A project documenting the composition and diversity of epiphytes (lichens and mosses) from pre-19th century vernacular buildings (see 'Historical Lichenology'). An inventory of species preserved on building timbers was compared to present-day species distributions, to estimate the magnitude and regional pattern of biodiversity loss across the boundary of industrialisation, and to infer drivers of this change. The results pointed to a significant loss of biodiversity from southern England, an impact which preceded the conservation ethic, and which has been discounted from the modern conservation agenda.

Ellis, C.J., Yahr, R. & Coppins, B.J. (2011) Archaeobotanical evidence for a massive loss of epiphyte species richness during industrialisation in southern England. Proceedings of the Royal Society B, 278: 3482-3489.

Yahr, R., Coppins, B.J. & Ellis, C.J. (2011) Preserved epiphytes as an archaeological resource in post-medieval vernacular buildings. Journal of Archaeological Science, 38: 1191-1198.

Yahr, R. (2010) Roundwood in roofs: archaeobotany in the attic. Thatcher’s Standard, 22: 10-11.

Yahr, R. & Ellis, C.J. (2009) Historic lichen communities in Wiltshire. British Lichen Society Bulletin, 105: 10-17.

Yahr, R. & Ellis, C.J. (2009) Lichens in the attic. The Building Conservation Directory, 2009: 13-14.

2009 - Population Dynamics of Lobaria pulmonaria in the Atlantic Hazelwoods of Western Scotland
by Sally Eaton (MSc - Biodiversity and Taxonomy of Plants)

This project compared the stand dynamics of a Scottish oceanic hazelwood, with the population dynamics of the dominant epiphyte, Lobaria pulmonaria. Thalli of L. pulmonaria were intensively sampled within a delimited area of hazelwood, and thallus presence-absence and abundance were examined using spatial statistics, and compared to local suitability of the hazel microhabitat. Results in spatial ecology were complemented by data on L. pulmonaria population dynamics (cohort establishment v. mortality rates, growth rates, and age to reproductive maturity), demonstrating the rapid population cycle for L. pulmonaria in the optimum climate of western Scotland.

2009 - Response of Lichens with Contrasting Growth-Form to a Standard Wetting-Drying Cycle
by Emma Goodyer (BSc - Plant Science)

This project used standardised wetting-drying treatments to examine the response of lichen species with contrasting morphologies (fruticose and foliose lichens) and with different photobiont partners (green-algal and cyanolichens). Results demonstrated a remarkable consistency in the response of lichens with contrasting morphology. This was explained by a trade-off in thallus water economy, between rapid water uptake to maintain photosynthesis, and a need to reduce excess water to maintain CO₂ gas exchange, under-pinned by physiological and biochemical mechanisms.

2008 - Effects of Climate Change on Montane Indicator Lichen Species
by Dafydd Crabtree (MSc - Biodiversity and Taxonomy of Plants)

Montane ecosystems are expected to be severely threatened by climate warming. This study examined the composition and physical structure of vegetation along three altitudinal transects in the Caingorm Mountains of north-east Scotland. Focussing on nine lichen indicator species, the results demonstrated peak occurrence of terricolous lichens at mid-altitudes. Peak occurrence occurred at a point where vascular plant growth (and competition) is reduced, though below a high-altitude area of open ground in which a facilitative structural canopy is absent. Results from the MSc formed the basis for a short research project funded by the Cairngorms National Park Authority - this extended project indicated that the critical interaction between vascular plants and lichens is maintained by both temperature and wind-speed. A modelling framework demonstrated the potential importance of wind-speed for downscaled bioclimatic projections. The data now form an important resource for long-term monitoring of vegetation change in the British mountains.

Crabtree & Ellis (2010) Species interaction and response to wind-speed alter the impact of projected temperature change in a montane ecosystem. Journal of Vegetation Science, 21: 744-760.

Crabtree, D. & Ellis, C.J. (2009) Monitoring ground-layer lichen communities in the Cairngorms: a base-line study to assess climate change impacts. Unpublished Report - Cairngorms National Park Authority.

2008 - Response of Lichen Species to Environmental Factors Operating at Multiple Spatial Scales
by Vivyan Lisewski (MSc - Biodiversity and Taxonomy of Plants)

This study examined the extent to which lichen occurrence and local abundance might be controlled by a series of nested environmental factors: macroclimate, site setting (i.e. interior woodland, wayside or streamside), and woodland composition (i.e. tree species). Four contrasting lichens were selected as target 'species': Degelia spp, Lobaria pulmonaria, Pseudevernia furfuracea and Sphaerophorus globosus. The study identified the effect of a general macroclimatic gradient on lichen occurrence, operating across Scotland from the more oceanic west-coast to the relatively continental north-east. However, local effects (woodland setting and composition) were important in controlling occurrence and abundance through an interaction with macroclimate. This points to the critical importance of local habitat in fully understanding the effect on species distributions of climate change.

Lisewski, V. & Ellis, C.J. (2011) Lichen epiphyte abundance controlled by the nested effect of woodland composition along macroclimatic gradients. Fungal Ecology, 4: 241-249.

Lisewski, V. & Ellis, C.J. (2010) Epiphyte sensitivity to a cross-scale interaction between habitat quality and macroclimate – an opportunity for range-edge conservation. Biodiversity & Conservation, 19: 3935-3949.

Lisewski, V. & Ellis, C.J. (2009) Evidence that browsing animals can have a significant effect on epiphytic populations of Sphaerophorus globosus in Scotland. British Lichen Society Bulletin, 104: 6-9.

2007 - Functional Rules and Species Traits Related to Epiphyte Community Succession in Mixed Aged Woodlands
by Jason Lewis (MSc - Biodiversity and Taxonomy of Plants)

A study to compare epiphyte community composition, (i) between different tree species (Betula spp., Pinus sylvestris and Populus tremula), and (ii) for a given tree species, between individuals of contrasting age. The research attempted to identify 'assembly rules' that might usefully describe the pathway of epiphyte succssion. Species life-history traits were used to circumscribe 'ecological guilds', and the temporal relationships between these guilds was assessed between different tree species (i.e. between epiphyte communities with contrasting species composition), to confirm or refute the existence of a common successional pattern.

Lewis, J.E.J. & Ellis, C.J. (2010) Taxon- compared to trait-based analysis of epiphytes, and the role of tree species and tree age in community composition. Plant Ecology & Diversity, 3: 203-210

2006 - Ecological Analysis of the 'Near Threatened' Lichen Epiphyte Vulpicida pinastri (Scop.) Gray in the British Isles
by Mark Binder (MSc - Biodiversity and Taxonomy of Plants)

An autecological study to examine the 'near threatened' lichen epiphyte Vulpicida pinastri. This species is largely restricted in Britain to north-east Scotland, where it occurs most frequently on juniper (Juniperus communis). We used a multi-scale approach to examine: (i) its biogeographic distribution in the British Isles, in relation to climate and habitat distribution, (ii) the role of dispersal and niche limitation controlling its local occurrence in juniper stands and (iii) its micro-habitat preferences within individual juniper shrubs.

Binder, M.B. & Ellis, C.J. (2008) Conservation of the rare British lichen Vulpicida pinastri climate change, habitat loss and strategies for mitigation. The Lichenologist, 40: 63-79.

Ellis, C.J. & Binder, M.B. (2007) Inferred shift in the British distribution of Vulpicida pinastri using herbarium and mapping data. British Lichen Society Bulletin, 101: 4-10.