Downes, B. J., et al. 2002. Monitoring Ecological Impacts: Concepts and Practice in Flowing Waters. Cambridge University Press, New York, New York, USA.

Amina Pollard

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Published: May 13, 2003

Given existing and projected human use and degradation of freshwater resources, it is increasingly important that rigorous monitoring programs be implemented in river and stream systems for purposes of conservation and management. Downes et al. (2002) provide a timely and coherent guide for the development of effective monitoring programs in streams. The authors, all ecologists, consider the components required for an accurate impact assessment and the design of monitoring programs that can detect specific human activities that are causing unacceptable changes to the environment. They focus on monitoring ecological impacts, rather than on compliance monitoring or general assessments of stream ecological integrity.

Monitoring Ecological Impacts: Concepts and Practice in Flowing Waters is intended for both professional and student ecologists and for resource managers interested in human impacts on the environment. Because much of the information it contains is a review of basic statistical design and stream assessment literature, this text may be particularly useful to those new to the field. The information can be comprehended by anyone with a basic knowledge of stream ecosystems, such as those involved with routine water quality monitoring, although the material is not intended for lay people with a general interest in human impacts.

The book is set up as a reference text, guiding the reader from general to specific information on effective ecological impact assessment of flowing water systems. It is arranged around three main objectives: developing a framework, providing practical research designs, and discussing potential obstacles to impact monitoring.

First, the authors provide a framework for determining the existence, magnitude, and effects of human impacts on flowing water. The book opens with a discussion of the need for and the aspects of good monitoring design. Here the authors also explore the nature of monitoring problems. Because it is difficult to rescue information from deficient research designs, it is important to develop logical, goal-driven monitoring programs. The implementation of these designs requires an understanding of the general ecology of riverine systems, the details of the design, and the order in which these issues should be addressed. The first section of the text offers a brief but comprehensive overview of these aspects.

Second, the authors present a theory-driven research design that is practical for a variety of human impacts and general enough to be used in any stream ecosystem. This section of the book provides a step-by-step reference for the different stages of thinking through and setting up a monitoring program. The development of a framework for making statistical decisions and testing hypotheses is described. Although the book focuses on familiar frequentist statistics, the logical framework for a monitoring program would apply irrespective of the statistical approach. The monitoring framework advocated throughout this text is a replicated before-after-control-impact (BACI) design, which allows for discrimination between effects caused by humans and those caused by natural processes. The body of the book provides the details for a range of different BACI designs and describes their applicability. This section also identifies the decisions that will be critical for achieving specific goals, i.e., the type of impact, inferential certainty, the selection of appropriate monitoring criteria, and sample size. Although the terminology and descriptions refer to stream systems, the basic principles discussed in this section may be of interest to people working with similar statistical design concerns in different ecosystems, e.g., patches in a forest.

Third, the authors offer potential solutions to traditionally neglected problems in impact assessments of streams. They discuss how ecologists and managers can optimize the costs of research design relative to the amount of information gained and address the balance between research and management action. This section may be of the most interest to ecologists and resource managers, because it is more discussion-oriented in comparison to the review and design material covered in the previous sections, which are more practical in nature. In addition, some of the successes and pitfalls reviewed here may be analogous to those found in other types of ecosystems. For example, it is common for scientists to think through a brief cost-benefit analysis of a particular research design regardless of the particular habitat of interest.

The book fufills its function as a reference guide by presenting decision-making and management protocols in a simple and logical order, and this organizational method is effective. However, at times the text suffers from being repetitive and dull. Although it seems that a single topic is sometimes spread out over several chapters, this is because the authors are trying to build on previously presented ideas. Fortunately, quickly identified reference aids, such as flow diagrams and end-of-chapter summaries, reinforce the direction in which they are going and the main points they are trying to make. Examples of monitoring programs follow the theoretical discussions to show how the ideas developed in the text can be implemented in actual cases.

This book is a useful and comprehensive guide for beginning ecologists and managers interested in assessing human impacts on stream ecosystems. As human-generated pressure for water resources increases in magnitude and extent, it is essential that we have the tools necessary to assess the status of flowing water systems. This book provides sufficient detail for the consideration of the qualities of an effective monitoring design. The discussion of BACI designs is comprehensive, and the authors provide additional references for a more exhaustive exploration of specific characteristics of each design. Overall, the argument presented in this book is complete and recognizes that the best approaches for monitoring ecological impacts will continue to evolve. However, this process of evolution requires that we begin to discuss a coherent approach to monitoring ecological impacts in stream and river systems, and this is exactly what the authors do in this book.

Downes, B. J., L. A. Barmuta, P. G. Fairweather, D. P. Faith, M. J. Keough, P. S. Lake, B. D. Mapstone, and G. P. Quinn. 2002. Monitoring Ecological Impacts: Concepts and Practice in Flowing Water. Cambridge University Press, New York, New York, USA. 446 pp., hardcover, U.S.$90.00, ISBN 0-521-77157-9.

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Downes, B. J., L. A. Barmuta, P. G. Fairweather, D. P. Faith, M. J. Keough, P. S. Lake, B. D. Mapstone, and G. P. Quinn. 2002. Monitoring ecological impacts: concepts and practice in flowing water. Cambridge University Press, New York, New York, USA.