An Ecological Database of the British Flora
Total Page：16
File Type：pdf, Size：1020Kb
An Ecological Database of the British Flora submitted by Helen Jacqueline Peat for examination for the degree Doctor of Philosophy Department of Biology University of York October 1992 Abstract The design and compilation of a database containing ecological information on the British Flora is described. All native and naturalised species of the Gymnospermae and Angiospermae are included. Data on c.130 characteristics concerning habitat, distribution, morphology, physiology, life history and associated organisms, were collected by both literature searching and correspondence with plant ecologists. The evolutionary history of 25 of the characteristics was investigated by looking at the amount of variance at each taxonomic level. The variation in pollination mechanisms was found at high taxonomic levels suggesting these evolved, and became fixed, early on in the evolution of flowering plants. Chromosome number, annualness, dichogamy and self-fertilization showed most variance at low taxonomic levels, suggesting these characteristics have evolved more recently and may still be subject to change. Most of the characteristics, however, eg. presence of compound leaves, height and propagule length showed variance spread over several taxonomic levels suggesting evolution has occurred at different times in different lineages. The necessity of accounting for phylogeny when conducting comparative analyses is discussed, and two methods allowing this are outlined. Using these, the questions: 'Why does stomatal distribution differ between species?' and 'Why do different species have different degrees of mycorrhizal infection?' were investigated. Amphistomaty was found to be associated with species of unshaded habitats, those with small leaves and those with hairy leaves, and hypostomaty with woody species, larger leaves and glabrous leaves. Species with arbuscular mycorrhizas occur in more habitat types than non- mycorrhizal species and also in habitats with a greater maximum pH. Annuals and wetland species, however, are typically non-mycorrhizal. Mycorrhizal perennials were also found to have heavier seeds than non-mycorrhizal perennials. 2 Table of Contents Acknowledgements 5 Declaration 5 Chapter 1 - Introduction 6 References 11 Chapter 2 - The Ecological Flora Database 13 Introduction 13 The Species 13 The Information 14 Methods of Data Collection 15 Structure of the Database 19 The Database Tables 23 References 37 Chapter 3 - Using the Ecological Flora Database 38 The Database Software 38 Getting Started:- 39 Using SQL*ReportWriter 44 Report Descriptions 4. 1. SPECIES_QUERY 42 2. CHAR_QRY_TEX 45 3. CHAR_QRY_NUM 46 4. CHAR_VAL_QRY 47 5. LINKl_COUNT 48 6. LINIC2_MEAN 49 Using SQL*Forms 50 The SPS_QUERY form 50 The CHAR_QRY form 51 Using SQL*Plus 52 Buffers 52 Editing Queries 53 Storing and Retrieving Queries 53 Saving and Printing Output 53 Setting Default SQL*Plus Commands 53 Sample Queries 54 Chapter 4 - An Investigation into the Antiquity of Ecological Characteristics in Angiosperms 64 Introduction 64 Method 65 Results 69 Discussion 83 References 91 3 Chapter 5 - Comparative Analyses of Ecological Characteristics 92 Introduction 92 Statistical Approaches 93 Analysis of Higher Nodes 93 Analysis of Covariance 94 Examples 95 Using a higher taxonomic level 95 Analysis of Covariance 96 Discussion 98 References 100 Chapter 6 - A Comparative Study of the Distribution and Density of Stomata in the British Flora 102 Introduction 102 The Data 107 Methods 111 Results 113 Discussion 119 References 124 Chapter 7 - The Distribution of Mycorrhizas in the British Flora 126 Introduction 126 Methods 130 The Data 130 The Analyses 131 Results 134 Discussion 149 References 156 Chapter 8 - Discussion 158 References 164 Appendix A 165 Appendix B 166 Appendix C 198 Appendix D 212 Appendix E 214 Appendix F 219 Appendix G 222 Appendix H 226 4 Acknowledgements I would like to thank Alastair Fitter for his help and enthusiatic supervision throughout the last three years, and all members of F2, both past and present. Especial mention, however, must be made to: Helen West, for always providing a sympathetic ear; Paula Smith, Mark Coulthard and Kevin Newsham for daring to share a house with me; and Steven Ford, for supplying me with a floor to sleep on whenever I was in London. This thesis was made possible by NERC and the British Ecological Society who funded the Ecological Flora Project. Declaration The research described in this thesis is my own and has not been presented before. The structure of the database, however, is based upon the prototype version designed by Andrea Bullock (Bullock, A.E. 1989. Florabase - a plant ecology database. MSc Thesis, University of York), and the choice of characteristics to include in the database resulted from discussions with members of the Editorial Board (Appendix A, page 165) who are helping to oversee the Ecological Flora Project. 5 Chapter 1 Introduction The necessity for a comprehensive account of the ecology of British plants was first stated by Salisbury (1928). In his proposition for the publication of a British Biological Flora containing information on the biology and ecology of British species, he wrote: "Much relevant information is to be found scattered through the multitude of botanical journals but is difficult to access. A great deal is also known to field-naturalists but has never been published, and is likely to be lost with the death of the individuals. It is proposed to incorporate in the Flora all accessible published observations together with the not inconsiderable mass of unpublished data. It is felt that such a compilation will be of great scientific value and at the same time provide the surest means of bringing to the notice of students the many lacunae that require to be filled." However, it was not until the 1940's that any progress towards such a flora was made. The 1940 Annual Meeting of the British Ecological Society decided to publish accounts of single species, or small groups of species, in the Journal of Ecology, with the aim that eventually a complete account of the biology of all British angiosperms, gymnosperms and pteridophytes would be available. Fifty years later, accounts are available for c. 200 species, approximately 10% of the British Flora. The number appearing each year has fluctuated between a few very productive years (10 in 1955, 12 in 1964) and years when only one flora was published (eg. 1944, 1965, 1989). There does not seem to have been any major changes in the rate of publication of Biological Floras, however, suggesting a complete account of the British Flora will not be available for another 450 years. Writing a Biological Flora is a major task due to the amount and completeness of information that is required. An author must be able to give details on distribution, habitat, substratum, communities, effects of frost and drought, morphology, perennation, reproduction, physiology, biochemistry, phenology, breeding system, seed production, germination characteristics, associated organisms, 6 diseases and history. If such information is not available in the literature then the author has to collect it himself, so the slow rate of production of Biological Floras is not really surprising. Progress has also been made in other directions. The need for floras to contain ecological information, in addition to descriptive and identification details, was recognised by Clapham et al. (1952). Flowering, fruiting and germination times, pollination and seed-dispersal mechanisms, life forms and chromosome numbers were included in their Flora of the British Isles. Other than updated editions of this flora, however, no further advances towards an ecological flora of the British Isles were made until 1988 and the publication of Comparative Plant Ecology (Grime, Hodgson and Hunt, 1988), the first comprehensive account of a large number of species in a single volume. This book contains standardized autecological accounts of 281 common vascular plants of the British Flora. These accounts resulted from vegetation surveys in the Sheffield region, which recorded characteristics such as pH, altitude, and habitat type, followed by laboratory screening of the common species to determine characteristics such as 2C DNA, germination requirements and relative growth rates. Literature searches for all the species were conducted but no attempt was made to do an exhaustive search. Some of the species included in Comparative Plant Ecology also have Biological Flora Accounts, but the two sources combined mean that there are easily accessible reasonably comprehensive ecological accounts available for only c. 22% of the British Flora An alternative to the autecological approach is to concentrate on a particular subject area, and to collect data on particular characteristics for lots of species, rather than lots of information on individual species. This approach has yielded valuable data in a number of areas, for example: first historical records (Clarke, 1900); pollination mechanisms and breeding systems (Knuth, 1906); seed dispersal mechanisms (Ridley, 1930); altitudinal ranges (Wilson, 1956); hybrids (Stace, 1975); and mycorrhizas (Harley and Harley, 1987) . Much effort has also been put into the recording of plant distribution both in Britain (Perring and Walters, 1962) and Europe (Tutin et al., 1964- 1980). 7 The majority of information on the ecology of British plants, however, is scattered over a wide variety of sources. Salisbury's 'multitude of botanical journals' has now become more of a myriad,