Plant Life of Quaternary Cold Stages: Evidence from the British Isles

West, R.G. ( 2000 ) Plant Life of Quaternary Cold Stages: Evidence from the British Isles. Pp. xi + 320 . Cambridge University Press , Cambridge . ISBN 0-521-59397-2 . Price £65 (hardback). Includes CD ROM. Professor Richard West has been at the forefront of the development of Quaternary science in the UK for some four decades or so. During this period, he has focused his attention on the investigation of a number of important Pleistocene sections and boreholes located throughout East Anglia and neighbouring districts, initially under the leadership of, but subsequently as successor to, Sir Harry Godwin at the sub-department of Quaternary Research in Cambridge. This work led to a steady stream of meticulous reports on the geology and plant history of the Pleistocene in Britain, with a number of these widely acknowledged to be classic and innovative publications. Indeed, his classification of different temperate stages of the Pleistocene, based on his analyses of pollen assemblage and plant macrofossil data published during the 1950s and 1960s, still underpins the terminology and structure of much of the stratigraphic scheme employed for the Pleistocene in the UK (Jones & Keen 1993; Bowen 1999). In view of his influential role in the development of the subject, his extensive experience of the study of exposed sediment sequences in a wide spectrum of geological contexts, and his insight into the influence of taphonomic factors on the fossil plant record, any new treatise by R.G. West on the interpretation of the Quaternary plant record surely merits close attention. This book presents a synthesis that complements West’s earlier works on the temperate-stage plant record, this time focusing on the accumulated fossil plant record from cold stage deposits in the British Isles. It is the first comprehensive treatment of its subject. West has not only scrutinized the pollen assemblage and plant macrofossil records of cold stage deposits recovered from many sites in the UK, but has also travelled extensively throughout Svalbard, the Canadian Arctic Archipelago, the Yukon, the North-west Territories and arctic Alaska to examine modern plant assemblages, in order to assess their potential as suitable analogues for understanding fossil assemblages. The book has three interwoven strands: an attempt to provide a coherent summary of the large amount of data obtained from cold stage floras from sites in the British Isles; a comprehensive, quantitative archive and classification of these data in the form of an electronic data base; and consideration of some of the general conclusions that can be drawn from this comprehensive record. This review will examine each of these strands in turn. The ‘raw’ data are the published and unpublished plant records (pollen and/or plant macrofossil assemblages) available to West up to the data-entry date of 1995. As a prelude to the interpretation of these data, Chapter 1 introduces the importance of the assembly of such a comprehensive archive. The questions posed, which such an archive can help to address, are rather fundamental ones, about the past distribution and behaviour of plant species, and about the use of the fossil plant record for reconstructing past environments, including climate conditions. Chapter 2 attempts to provide a general geological setting (stratigraphic scheme and definitions, dating of sequences, glacial limits in the British Isles), while Chapter 3 introduces the typical sedimentary environments in which the various fossil records probably accumulated, as well as the range of taphonomic problems with which the Quaternary palaeobotanist has to grapple. I suspect that the three introductory chapters will prove somewhat confusing for readers not familiar with the underlying stratigraphic terminology and concepts. On the other hand, the treatment seems too skeletal for those more expert in the field, who will nod enthusiastically at the mention of various stratigraphic or taphonomic issues, but who, like me, might feel a little frustrated with the relatively limited treatment they receive. However, I do recognize the ‘no-win dilemma’ that West must have faced in trying to satisfy both constituencies. Nevertheless, many readers will surely be discouraged by the use of such terms as ‘palaeolithoclimatic’ and ‘palaeobioclimatic’ in early passages of the book, terms that are likely to be confusing for some, while raising questions in the minds of others about their specific definition and application. The sites from which the records were obtained are introduced in Chapter 5. The geographical bias of the data from the British Isles becomes apparent immediately, with the vast majority of the records from central and eastern England. This mainly reflects the preponderance in these parts of the country of records for intervals that predate the last glacial stage. In other districts, any comparable records that existed in the past have largely been removed by advancing ice sheets, or periglacial or other processes that promoted ground surface instability. However, it also reflects the region of main interest to West. A number of important records have been omitted. For example, there are only three records listed from Scotland (including the Scottish Islands), four from Ireland, one from the south-west counties of England, and none from Wales. The records included in the data base vary markedly in the number and type of fossils represented, their age, their state of preservation, and the sedimentary context inferred for the period during which they accumulated. These and other constraints on the data are laid out clearly by West, who also discusses some of the uncertainties these constraints introduce. Chapter 4 describes the electronic archive, which is captured in a CD ROM distributed with the book (included in purchase cost). The electronic formatting and structure take a little time to get used to, as the data are presented in ASCII comma-delimited macro-files. While these can be opened and manipulated in EXCEL, I could find no explanation of the necessary procedures that would assist the novice. The tables provide quantified information for each site record on number and type of taxa recorded, the modern habitat for each taxon, modern distributions, and stratigraphic age of records, as well as bibliographic details for sources of the ‘raw’ data. They are not, however, instantly illuminating, and quite a bit of work is required on the part of the operator to establish what meaningful patterns are locked in the data. This raises the question of the usefulness of circulating the data in this manner. Most readers would, I am sure, have preferred the data to have been presented in a more digested and/or interactive format whereas those intending to use the data for research purposes could easily access them if they were made available through the internet. Chapters 6–12 range through various biogeographical parameters that can be inferred from the data, based on (inter alia) the elements of the flora represented, the frequency of occurrence of selected taxa, species variability, and aspects of growth, reproduction and dispersal. Here is where it could have been extremely useful to have been able to work in tandem between the text and the CD ROM, but I could not find a quick way of achieving this. Those more expert in the handling of data bases might have greater success, but for those less practised in the art, some pointers would have been useful. Chapters 11 and 12 present some of the West’s broad conclusions concerning the habitats represented in the data base, as well as certain phytogeographical inferences that emerge from his analysis of the full data base. The third section of the book constitutes the many valuable insights into the problems of interpreting fossil plant records from cold stage deposits. These are scattered throughout the volume, so that the reader has to work hard to find and link them together, with the result that impact is not maximized. There are interesting comments made at irregular intervals about the distinctiveness of the cold stage floras of Britain, and how they differ, sometimes quite markedly, from present-day arctic floras. For example, therophytes occur in relatively high percentages in fossil floras compared with modern arctic communities. There are intriguing questions raised, for example, about the consequences of the development of an arctic-like environment at the latitude of the British Isles, for plants and insects. Again, however, I craved some further conjecture from West as to plausible answers to these questions. The final chapters address some broader themes, such as palaeoclimate reconstructions based upon biological and other information, comparisons of plant records with contemporaneous records of other biota, and a discussion of the ‘Origin and fate of the cold stage stadial flora’. These raise a number of issues familiar to Quaternary palaeobiologists, the overarching thesis being that the biomes that developed in low-latitude regions during ‘stadial’ times were not analogous to those that can be observed in northern latitudes today. There is a cri de coeur in the book for a new terminology to describe past formations, which is independent of the terms applied to define modern formations that have strict climatic connotations. West suggests that the new definitions could be based on the inferred physiognomy of the past vegetation, the benefits of which are not immediately apparent. This may introduce as many problems as are solved. Yet again, a fuller discussion of the issue would have been welcomed. Overall, I have mixed feelings about the book. On the one hand, the data base is an extremely valuable one, and we Quaternary scientists should be grateful to West for pulling all of this information together in a condensed fashion. On the other hand, I did feel that perhaps the opportunity was not grasped to turn a worthy book into a more exciting one. As already noted, there are places where the crucial arguments are not developed enough. There are also some surprising omissions. For me, the most surprising of all is the lack of any significant reference to recently published ice-core records, and to the implications they have for the interpretation of past ‘stadial’ and ‘interstadial’. The remarkable GRIP and GISP records of the last cold stage, for example, which have evidence for up to 24 extremely abrupt and quasi-cyclic Dansgaard–Oeschger cycles (warmings of some 7 °C), raise some fundamental questions of relevance to interpretation of the terrestrial record, as do detailed marine records for the last cold stage, which provide evidence for less frequent, but equally significant, Heinrich Events. These were dramatically sudden cooling events that appear to have had global impacts (Leuschner & Sirocko, 2000). The growing evidence for frequent, very short-lived climate oscillations during cold stages calls into question traditional definitions of ‘stadial’ and ‘interstadial’ events and their associated floras. The likely responses of biota to this kind of oscillatory palaeoclimate background are very difficult to envisage, and represent a challenge to palaeobotanists for future research. Presumably the starting point for such a pursuit is the construction of rigorous archives of the fossil record of the type assembled by West, followed by close scrutiny of the data they contain. It seems quite apt, therefore, that his book closes with the following statement: The database given here (to 1995) can be expanded as new fossil assemblages are described, as taxonomy and definition improves, as dating is improved and as stratigraphy is revised. The present database and the interpretation of cold stage floras discussed here will hopefully form a sound basis for these developments. True, but it is not made clear whether this final message is an invitation to the community to participate in making this a community-shared facility. I hope it is. This book should be considered an essential addition to libraries and laboratories that aim to maintain a comprehensive coverage of publications in Quaternary stratigraphy and/or palaeobotanical research. It is also a key reference for all those embarking on research projects in Quaternary palaeobotany, and a useful reference for those on the fringe of this specialist subject. With respect to the quality of production of the volume, the cover design and fabric, paper and print, and the colour photographs are all of excellent quality. The line diagrams are generally well constructed. Sadly, some of the black-and-white photographs lack contrast, and I could not read the scales in one or two. But, on the whole, it is quite an attractive little book.

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