QUATERNARY RESEARCH 25, 263-265 (1986)

BOOK REVIEWS

Genesis and Classification of Cold Soils. By Samuel Rieger, Academic Press, Orlando. 1983, 230 pp.. $35.

Recent books in soil genesis and pedology have fol- lowed a number of different approaches. While this seems to be eclectic and original it betrays the fact that this young science-about 100 years old-is still in a transition stage. Acknowledging that soil genesis deals with the processes involved in the formation of soil, it would appear that a discussion of these pro- cesses, in the different geographical regions of the world, could be a natural approach. Unfortunately the soil forming processes are very complex and in many cases not well understood. Nevertheless this situation has not prevented, especially the European pedolo- gists. writing books with strong emphasis on pro- cesses.

In the United States, the adoption of the Soil Con- servation Service new soil classification-the Soil Taxonomy-has polarized the efforts of pedologists toward the classification of soils rather than their genesis. Dr. Samuel Rieger has chosen to discuss the soils of the cold regions in the context of the U.S. Soil Taxonomy. By making this choice, Rieger has “boxed” himself into an unyielding situation that has prevented him from tempering the rigid frames of the taxa with ecological and biogeographical consider- ations. This comment should not detract from the fact that the book is very informative and assembles a vast literature into a coherent body.

The book consists of 13 chapters, 9 of which deal with the six soil orders that occur in the cold regions; 1 with the principles of the U.S. Soil Taxonomy; 2 with the temperature regimen and the freezing phe- nomena of the cold soils: and 1 with other world clas- sifications.

The subject in each chapter is well presented, well researched, and relatively up-to-date. This diligent work could have been greatly improved if Rieger had provided some historical background on the develop- ment of soil science in the cold regions, included ade- quate maps for leading the reader through the gener- ally unfamiliar arctic and antarctic regions, adopted a single nomenclature for periglacial features, avoided ambiguity between frost table and permafrost table, redrafted some of the borrowed figures presently illeg- ible, updated the concept of mechanical disintegration due to frost, clarified the point that moisture in the soils of the coastal plains of Alaska is more dependent on the texture of the soils than on precipitation, and finally acknowledged the existence of a soil nomen-

clature and classification introduced by Tedrow and his associates since the fifties. that not only has an historical value but is still in use by ecologists.

Notwithstanding these deficiencies Rieger has added a concise recapitulation of the soil conditions and distribution in the cold regions. His first-hand ex- perience with cold soils gained by a long tenure in Alaska with the Soil Conservation Service adds conti- dence to his explanations and gives him the ability to relate soils of other sectors. Also his familiarity with the Soil Taxonomy is definitely an asset: it provides direction for those who want to learn about this system and its applicability in the cold regions. With many activities in arctic Alaska directed to use the pe- troleum reserves of this vast land, the book of Rieger is timely and indispensible.

FIORENZO C. Uoo~rur Depurtment of Forest Resource,\

Unil,ersity of Washington Scuttle. Wushington 9812.5

Past and Present Vegetation of the Far Northwest ofCanada. Edited by J. C. Ritchie. Univ. of Toronto Press, Toronto, 1984, 251 pp.

This small but significant volume, aimed primarily at researchers and students in Quaternary studies. achieves the distinction of being a scholarly treatise on plant paleoecology while remaining accessible to nonexperts in the field. The book is the culmination of two decades of work on the late Pleistocene and Holocene of the northern Yukon and MacKenzie delta region, much undertaken by Ritchie and his co- workers, and documents a productive first phase of paleoecological investigations.

A brief introduction sets both the geographical and scientific scene, and is followed by two concise and informative chapters on the physical environment and floristics of the region. Chapter 4 summarizes infor- mation on modern vegetation and is augmented by photographic plates and tabular summaries of the composition of major community types. sensibly placed in an appendix. The region is discussed in the context of Beringia, for while unique in some aspects, events in northwest Canada were undoubtedly related to those in other parts of Beringia. a fact that becomes clear in the chapters that follow.

The reader is thus well prepared for the important core of the book, two relatively long chapters on veg- etation history and paleoenvironmental reconstruc-

263 0033-5894/86 $3.00 CopyrIght G 1986 by the Umverwy of Warhmgtm All nghta of reproductmn III any form reserved.

264 BOOK REVIEWS

tion. The “facts” of the former are kept separate from the “interpretations” of the latter, which of necessity sometimes enter the realm of imaginative speculation. Ritchie is to be complimented on the care he takes to differentiate these for the uninitiated reader; much confusion has arisen in Quaternary science when a particular paleoecological reconstruction, one of sev- eral possibilities, is taken as gospel by enthusiastic but uncritical workers in other fields.

Tertiary and early-to-middle Pleistocene history is treated briefly; the late Pleistocene and Holocene pollen and macrofossil record is described in detail. Ritchie has ably condensed major features of interest into a clear text accompanied by simple. carefully de- signed figures. Radiocarbon dates, pollen frequency and influx, and macrofossil information are provided. Paleoecological reconstructions are presented in the form of alternative hypotheses, and the evidence for and against each hypothesis is discussed. Such issues as evidence of a very early Holocene temperature maximum, the nature of species migrations, and changes in the forest-tundra boundary should interest climatologists, plant geographers, and ecologists as well as paleoecologists. In some cases Ritchie is par- tial to one hypothesis, but the reader is always left the final choice between interpretations, a refreshingly open-minded approach.

The final chapter, a short review of current prob- lems, dwells largely on the fascinating but thorny questions of the carrying capacity of the Beringian “steppe-tundra” and its relation to the Pleistocene megafauna. These are complex topics, and the discus- sion is unfortunately limited to a few pages. However, some interesting new ideas are raised. Ritchie’s closing words caution us that “the continued progress of plant paleoecology . . will always lean heavily on the products of serendipity,” but the message from northwest Canada is clearly that this region is an ex- citing and fruitful one for paleoecological studies.

The concluding paragraphs examine likely avenues for future investigation, and one is encouraged that the researcher who is equipped with merely average luck could expect to make useful contributions in key areas of plant paleoecology and help answer questions of interest in ecology, paleontology, archaeology, clima- tology, and plant geography. Thus a broad range of people interested in northwest Canada, Alaska, or Beringia in general may wish to consider this book. Quaternary scientists certainly should, and I also rec- ommend it to plant ecologists as it provides an excel- lent historical perspective on a fascinating region.

Not least among the merits of this volume is its size. It must be the smallest of its kind, and you will be happy to know that it fits on a normal bookshelf. While it is true that pollen diagrams from the far north have relatively few major taxa. the diagrams in this book should nevertheless win a prize for simplicity, clarity, and ease of comprehension. The writing is el- egant and concise, the text free from typographic

error, and key references are helpfully included in the index. The chic black end papers might have served better as a detailed reference map, but that is a minor point. Of much more significance is that the book is published at an affordable price. It is an excellent con- tribution to Quaternary plant ecology.

MARY EDWARDS College of Forest Resources AR-10

University of Washington Seattle, Washington 98195

Quaternary Extinctions. A Prehistoric Re\>olution. Edited by Paul S. Martin and Richard G. Klein. Univ. of Arizona Press, Tucson, 1984, 892 pp., $65.

Mass-extinction events attract scientific attention because of their unique potential to provide an under- standing of how species adapt to environmental changes. Fauna1 extinctions in the late Quaternary were insignificant in terms of the diversity and number of species lost when compared with the extinction events of the Permian/Triassic and CretaceousiTertiary boundaries. The attraction of the late Pleistocene event lies in the temporal proximity of a mass extinc- tion that was apparently selective against large-bodied mammals and in the possibility of man’s involvement in this event. An appreciation of differences in timing and magnitude of losses between continents and oce- anic islands, the apparent simultaneous appearance of hunting cultures, and the environmental changes caused by terminal Pleistocene climatic events are es- sential to an understanding of late Quaternary extinc- tions.

Two widely accepted classes of models have been proposed to account for the Quaternary extinctions: those models citing climatic/geologic causes and those proposing man as a significant causal agent. In 1967, Pleistocene Extinctions: The Seurch for a Cause, edited by Paul S. Martin and H. E. Wright, Jr. sum- marized current knowledge of the event. In Quater- nary Extinctions, the editors aptly refer to the out-of- print parent volume as obsolete. Quaternary Extinc- tions is a new synthesis, not just an update of the earlier work. It incorporates the maturation of models that now encompass more interdisciplinary data. De- velopments in radiocarbon dating, modern ecological theory, and a global expansion in research facilitate greater understanding of late Quaternary events. At a time of heightened interest in mass extinctions the ar- rival of this volume is timely.

The complexity of the late Quaternary extinction events and possible underlying causes is reflected by the eclectic range of topics, that at times appear al- most marginal to the issue. The volume consists of 38 contributions from 47 authors, well organized into six sections covering nearly 900 pages. Chapters sharing a common theme are organized into sections, each pref-