Research on biodiversity and climate change at the Royal Botanic Garden Edinburgh
Volume 4 Number 2 - July 2007
Christopher Ellis and Mary Gibby
The Royal Botanic Garden Edinburgh (RBGE) in Scotland holds living collections of 15,600 species across four gardens, over 2.5 million preserved herbarium specimens, and provides expertise in the science of botanical diversity, e.g. taxonomy, systematics, evolutionary biology, population genetics and conservation biology of plants and fungi. This represents a valuable scientific resource directly relevant to major challenges posed by climate change. Human-induced global warming will significantly threaten levels of biodiversity (Hannah et al., 2002; Parmesan & Yohe, 2003; Travis, 2003; Thuiller et al., 2005) with concerns over the subsequent loss of ecosystem services - biological resources, environmental services and ecosystem function (Hooper et al., 2005; Diaz et al., 2006; see Figure 1).
This importance of biodiversity as the natural framework underpinning social and economic sustainability is internationally recognized and was legally ratified by the Convention on Biological Diversity (CBD Secretariat, 2007) and its lower-level frameworks (Europa, 2007; UK Biodiversity Action Plan, 2007); accordingly, biodiversity science provides a fundamental link between the physical process of climate change and subsequent impacts on social and economic wellbeing (Figure 1).
Climate change science at RBGE can be grouped into three interrelated themes: prediction, monitoring and evolutionary response (Fig. 2). RBGE research uses statistical models to predict the impacts of climate change on biodiversity (e.g. the response of species to IPCC scenarios) indicating which species or vegetation types may be threatened by climate change and should be closely monitored or protected (e.g. by translocation or the mitigation of other stresses). Monitoring seeks to observe the response of sensitive elements of Scottish biodiversity to climate change, providing a robust measure of change in the flora, and identifying opportunities for mitigation. However, monitoring is itself an important mechanism with which to verify model projections and thereby calibrate and improve the predictive ability of modelling studies. Prediction and monitoring thus describe the impacts of climate change on species, providing a base-line for conservation strategies (e.g. adaptation and mitigation); however, at a fundamental level the impact of climate change on biodiversity will be determined by population genetic processes (e.g. metapopulation dynamics and the ability of species to migrate through fragmented landscapes and the potential for genetic adaptation to different and possibly novel climates).This work is supported by research into the effect of past climate change on vegetation structure and function (Brncic et al., 2006. Ellis & Rochefort, 2004, 2006).
A number of individual research projects dealing with climate change are now well-developed and others are in the ‘development stage’ (project planning, grant applications pending etc.).
Phenology is the study of recurring seasonal events, such as flowering and leaf-fall in plants and hibernation and migration in animals. Parameters such as the date and duration of flowering can be compared with climatic parameters such as temperature, rainfall and humidity to see if there is any correlation. Phenological research at RBGE dates back to 1850, when the Curator, James McNab first recorded the flowering dates of more than 40 species. The current phenology programme at RBGE has been running for the past five years and involves recording the frequency and duration of flowering and stages with each flowering season and changes in foliage for over a hundred species. These data will increase the understanding of the mechanism in plants which responds to climate changes and will enable scientists to predict how plants will respond to climate change. Over the past five years early spring has been getting warmer and some springflowering plants flower more than two weeks earlier (see Figure). It is a unique experimental opportunity comprising plants from regions across the world, growing at a single site, and subject to the same approximate climatic variation.
The phenology programme based at RBGE is in collaboration between staff and research associates in the Science and Horticulture Divisions and volunteers. The programme includes a daily monitoring project, a weekly monitoring project and the special examination of Rhododendron species. These studies include the development of semi-quantitative rapid-survey methods for monitoring phonological characters (Harper et al., 2004; Harper & Morris, 2006).
The Scottish Forestry Phenology Project aims to establish a network of sites based on RBGE’s climatically contrasting Scottish gardens (at Edinburgh, Dawyck, Logan and Benmore) and including Dundee Botanic Garden. The details of the project remain to be resolved, though it is envisaged that it would be undertaken in collaboration with key stakeholders in Scottish forestry and would provide information relevant to the forest industry (i.e. phenology of material of known genetic stock under different climatic conditions). The International Phenology Gardens Project is coordinated by Humboldt University (Berlin), with sites throughout continental Europe. The project monitors the phenology of cloned material for a range of tree species. RBGE is currently establishing a site at its garden at Dawyck which, for Scotland, has an unusual cool continental climate and will provide important new data for the project.
A significant body of climate related research focuses on monitoring and predicting the impact of climate change on Scottish cryptogams. Cryptogam species (i.e. mosses, liverworts, lichens, fungi and ferns) are one of Scotland’s most important contributions to international biodiversity (Mackay et al., 2001; Gibby, 2003). RBGE studies include research to optimise patterns of habitat structure (e.g. patterns of woodland isolation and connectivity) aimed at ensuring the effective response of Scotland’s internationally important cryptogam communities to future climate change (Ellis & Coppins, 2006, 2007a, 2007b).
Snow-bed ferns: In the UK, the fern Athyrium distentifolium is expected to be threatened by the effects of climate change. It is restricted to areas of late snow lie in the Scottish mountains and a current research monitoring programme has already shown that populations can be devastated by reduced snow cover in winter (McHaffie, 2006). The Scottish endemic Athyrium distentifolium var. flexile differs in its reproductive capacity from A. distentifolium (e.g. producing ripe spores earlier in the season), and it may show a different response to the changes in climate (McHaffie et al. 2001).
Species-response: Research using predictive models to examine the projected response of lichen species to climate change, including the interaction between climate-response and habitat structure (i.e. patch extent, fragmentation and limits to dispersal). This predictive information aims to guide the decision making process for a long-term conservation strategy. Greater understanding of the interaction between climate and habitat is essential in developing mitigation strategies for sustainable forestry projects.
Climate indicators: Lichens are popularly applied as sensitive bioindicators. Research currently in the development phase is seeking to set up a network of monitoring sites, to examine the response of lichen species to changes in climate. Selected species will potentially include sensitive arctic-alpine elements of Scotland’s montane flora. This project will be established to complement studies in species-response (above), contributing to calibrating predictive models.
Snow-bed bryophytes: A new study is currently setting up long-term permanent plots, aimed at monitoring the response to climate change of Scotland’s bryophyte-rich snow-bed communities. The study is in partnership with Scottish Natural Heritage.
Molecular ecology at RBGE continues to make an international contribution to biodiversity research and conservation, and this research programme has been extended to address genetic adaptation to climate change and possible mitigation of the effects of the changes in climate.
Bluebells: A project examining the ecology of native and non-native bluebells includes experimental work to examine the competitive performance of different species along climatic gradients. The study aims to broaden the debate from a single species response to climate change to a greater understanding of species interactions. It also provides an important practical assessment for the potential effects of climate change on a threatened native and non-native species.
Gene Flow and adaptation: Existing molecular studies use data to examine the potential of species to adapt to environmental change (i.e. through sexual reproduction and selection). Populations might acquire adaptive variation from elsewhere (i.e. there might be a potential to introduce genetic variation from other populations of the species either artificially or naturally if seeds/pollen can travel over large distances). Molecular studies can examine the dispersal ability of species which will estimate their potential to migrate through patchy or fragmented habitats in response to changed climate. Recently such studies have focussed on conservation priority species. The current programme is examining diversity in species of Scotland’s Caledonian pinewoods in collaboration with the Macaulay Institute and Scottish Crops Research Institute. This addresses the amount of climate related genetic variation between and among populations and the in situ adaptive capacity of species, i.e. can adaptive variation relevant to contrasting climates be dispersed across a species’ range?
Flora projects contribute principally towards RBGE’s commitment to biodiversity research and education. However, a number of projects have recently adapted this role to provide data relevant to climate change research.
Socotra: Research on the flora of Socotra has included student projects to examine the effect of climate change on areas of relict woodland (including sites on the Yemen mainland). However, the climate of Socotra is strongly controlled by small-scale topographic variation (e.g. effect of altitude), which combined with a lack of high resolution climatic data make this type of research especially challenging. The team are pursuing opportunities aimed at improving the predictive potential of climate-response models, and continue to work with local communities on issues relating to climate change and sustainable land-use.
Nepal: The flora of Nepal project has expanded its data collection from taxonomically relevant morphological characters to include additional species functional traits. These data are potentially relevant to monitoring and predicting the response of the vegetation structure and ecosystem function to climate change, and have strong potential for an integrated study with the phenology project (above). The team have established strong links in Nepal and they provide botanical expertise to organisations undertaking studies to investigate and mitigate the effect of climate change on plants (e.g. IUCN Nepal and WWF Nepal). The team are working with the British Council in Nepal to facilitate educational events that aim to promote climate change awareness, and with support from Darwin Initiative funding for 2007/2008 will supervise a Nepalese MSc student in a climate change study.
Tropics: The tropical group use phylogenetics and population genetics to understand how tropical species have responded to past environmental change. This includes palaeoecological data to examine the response of vegetation structure and function to past human socio-economy and climate change, as well as comparing reconstructed speciation rates to past periods of environmental change. Their projects examine the evolutionary potential of species to adapt and respond to climate change in the longterm (Pennington et al., 2005).
China: 1. Professor Yang Yong-ping, Deputy Director of Kunmimg Institute of Botany, is developing a long-term monitoring project to examine environmental change in the Hengduan Mountains of China. The foundation for this work is the capture of information on all the plant records from the region, through digitisation and databasing of herbarium records. With its rich collections of plants from Yunnan, dating back over 100 years, RBGE will be a partner in this project to provide information from our collections. 2. This work will be underpinned by current research on palaeoecology, vegetation history and climate change from the Quaternary to the present day. This research is a collaboration of RBGE with Professor Li Cheng Sen and his students at the Institute of Botany, Beijing. 3. Finally, the RBGE archive collections of photographs of Yunnan by George Forrest that illustrate past vegetation distributions and extent of glaciers will also contribute to the project.
RBGE also provides indirect though important contributions to climate change science, for example:
Archives: RBGE photographic archives have been used by international scientists in time series studies examining landscape change (e.g. the altitudinal migration of floristic zones, or shifts in glacial features). Such studies include scientists from the Joint Nature Conservancy Council (UK) and Lakehead University (Ontario, Canada), and Kunming Institute of Botany. The archives also house a massive amount of phenological data (1906-1939) which has been extracted and examined by University of Edinburgh researchers.
Diatoms: RBGE undertakes fundamental research in the systematics and identification of diatoms. Diatoms are photosynthesising, microscopic algae; they have a siliceous skeleton and are found in almost every aquatic environment including fresh and marine waters and soils. Diatoms provide one of the most powerful palaeoenvironmental indicators and are used in palaeoclimatic studies as the basis into knowledge of the climate system. Principal palaeoresearch groups both in the UK and internationally consult with the taxonomic work carried out at RBGE, in order to resolve and interpret palaeoenvironmental records.
Climate change is a rapidly developing theme in RBGE’s programme of education and public outreach. With its popularity and range of visitors, RBGE is uniquely placed to engage in wider public education and discussion on climate change issues. The Gateway Project under development will include as part of its major thematic events and exhibitions: ‘Climate Change – Scotland’ and ‘Climate Change – Global’.
Christopher Ellis and Mary Gibby
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