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  • Ecological Restoration, Second Edition: Principles, Values, and Structure of an Emerging Profession by Andre Clewell, James Aronson
  • Joy Zedler (bio)
Ecological Restoration, Second Edition: Principles, Values, and Structure of an Emerging Profession
by Andre Clewell and James Aronson . 2013 .
Washington, DC : Island Press . 336 pages. $60 hardback.
ISBN: 9781610911672 . $30 paperback.
ISBN: 978-1610911689 .

This book was written for students considering careers in ecological restoration. Nine chapters divided into three parts describe why, what, and how we restore. A final three chapters in Part Four describe the professional practice of ecological restoration. Interspersed throughout the book are seven “Virtual Field Trips” (VFTs) to restoration sites, authored by project participants from around the world. These contain both useful knowledge and opinion.

The authors characterize restoration targets as “legacy, utility, or recovery,” acknowledging we can’t always turn back the clock. They advocate a narrowly defined “discipline” of ecological restoration, saying in Chapter 12 that contesting boundaries for the field “cripples its capacity to be a game changer in our efforts to help global society regain a semblance of environmental sanity—and security—in the Anthropocene era.” They also suggest several criteria for recognizing and evaluating ecological restoration. One criterion is to assist recovery, recognizing that we cannot control many of the processes that influence ecosystem development. Another, providing historic continuity, appropriately allows multiple trajectories and outcomes. But does selecting and planting co-adapted species really guarantee historic continuity?

Building the case for ecological restoration as a discipline, Chapters Three and Four review ecological principles, emphasizing stressors that alter ecosystems to points where restoration is needed, and how recovery differs from gardening, agriculture, horticulture, and engineering. The authors offer insights on diverse opinions within the science of ecology, and call for discrete boundaries between concepts that are blurred, such as degradation, damage, and destruction. They insist that ecological restoration be distinct from rehabilitation, reclamation, revegetation, and remediation—all of which are considered separate disciplines—to facilitate “effective communication and collaboration.” The reasons for these distinctions are not always clear. For instance, how is a subtle distinction between intervention and manipulation useful in describing restoration strategies? Can ecological restoration be entirely distinguished from ecosystem creation, such as whena new vernal pool is excavated to restore a vernal pool landscape? And can we identify historical ecosystem boundaries well enough to know if we are restoring or creating target ecosystems? Either practitioners need precise guidelines, or rigid concepts need softening. The latter seems more practical.

Chapter Five concerns eleven outcomes of restoration: four ecosystem attributes that practitioners can supply directly and seven that emerge beyond our control. They are prescribed in sequence, but a different order may be needed for wetland restoration.

The authors do not define failure, but ecological restoration is considered to be successful when “biotic expression falls within a range of variability that was determined from multiple reference sites.” Left unanswered is the question of how much variation is acceptable. The authors also argue against using trajectories to evaluate restoration, saying “too many environmental, biological and ecological variables exist for a trajectory to have rigorous predictive value.” Because of the many uncertainties, I prefer the term “progress,” [End Page 77] which allows gradual, quantifiable responses to the subjective, yes-or-no judgment of “success.”

Chapter Six retells the long history of human impacts. I was puzzled as to why restorationists were told not “to continue manipulating species populations indefinitely” and that the product of those manipulations should not be called an ecological restoration. Wisconsin’s prairies, which early humans burned often, still require frequent burning to manipulate invasive woody plants. We call that restoration and consider those biomes and landscapes to be products of both pre- and post-human events, unlike the authors’ suggestion that ecosystems were intact prior to impairment by humans. As an example, Wisconsin vegetation would be difficult to interpret without reference to glaciers.

Chapters Seven, Eight, and Nine comprise the “how-to” section, with planning and restoration suitably organized in order of increasing effort to achieve goals. A note that sometimes less effort will suffice is tantalizing, but it is often hard to predict how much effort will be necessary to achieve restoration goals. The...

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