Climate change and human action have influenced, separately or in concert, the development of vegetation and landscapes worldwide. For the paleoecologist several questions naturally follow: Can we distinguish climatic from anthropogenic effects in the geologic record, and can we determine when they have interacted to create a particular set of conditions? Scientific philosophies and traditions, the tools available to paleoecologists, and site-specific factors all qualify our answers, as the contributions to this volume effectively illustrate. Most of the examples are from Britain, and from the North American viewpoint they clearly illustrate differences in approach between European and North American scientists.
The inspiration for the book is the work of Professor Alan Smith. In a long and distinguished career in Britain and Northern Ireland, he has considered many aspects of how human impact and climatic change influence landscape evolution. He also played a key role in developing applications of radiocarbon and dendrochronological techniques to paleoecological studies. Chapters by a wide range of authors examine the current limits of paleoecology, developments in environmental archaeology, and technique and interpretation in the light of new practical and theoretical developments.
The book has four parts. The first addresses the spatial and temporal limits of paleoecological studies that address human impact. Birks reminds us that, to appreciate the historical record of human impact on the environment, we must work a t high levels of spatial and temporal resolution to separate the interacting roles of people, climate, and ecological processes. Chapters by Pilcher and Baillie show how AMS dating and refined tree-ring techniques now allow us to describe various human activities with much greater temporal precision than before; in particular, tree rings can sometimes provide details as to the season, as well as the year, of various human activities. The precision possible in this kind of paleoecology not only affords us reconstructional detail, but it also lends itself to the deductive approach; Oldfield reminds us that, with good control over chronology and data, we are in a position to test hypotheses rather than merely to generate empirical data for post hoc interpretation.
The second part on climatic change is the least convincing. In contrast t o human impact, patterns of climate change emerge a t large geographic scales. At the smaller scales addressed in this book the role of climate is often ambiguous, and local change in the records actually becomes noise that obscures the climate signal. Blackford and Matthews tackle the problems posed by peat bogs and arctic-alpine soils, repectively, as repositories of climatic information; the conclusion is that neither are tractable systems. Lowe demonstrates that even a regional vegetation history for Scotland needs a still larger geographic context in order to extract climatic information reliably. However, Bradshaw provides an interesting set of examples that illustrate the complex interaction of climate, ecological processes, and humans, and shows that in the right context these factors can be distinguished in the record. Bradshaw reminds us that fire is perhaps one of the most important factors that mediates vegetation response to climate; as fire is used by humans in many contexts, its application (or suppression) can alter the climate-vegetation relationship in a