The Historical Ecology Handbook: A Restorationist's Guide to Reference Ecosystems

By Dave Egan and Curt Meine

The Historical Ecology Handbook makes essential connections between past and future ecosystems, bringing together leading experts to offer a much-needed introduction to the field of historical ecology and its practical application by on-the-ground restorationists.

Chapters present individual techniques focusing on both culturally derived evidence and biological records, with each chapter offering essential background, tools, and resources needed for using the technique in a restoration effort. The book ends with four in-depth case studies that demonstrate how various combinations of techniques have been used in restoration projects.

The Historical Ecology Handbook is a unique and groundbreaking guide to determining historic reference conditions of a landscape. It offers an invaluable compendium of tools and techniques, and will be essential reading for anyone working in the field of ecological restoration.

• Language: English
• Publisher: Island Press
• Release date: Aug 12, 2005
• ISBN: 9781610913348

Book preview

2000

Preface to the 2005 Edition

Harvesting the Past to Plant the Future

The Historical Ecology Handbook: A Restorationist’s Guide to Reference Ecosystems was designed to fill a fundamental gap in the ecological restoration toolbox—a study of the techniques and methodology restorationists can use to develop reference models for their work. As its editors, Evelyn Howell and I hoped the book would encourage restorationists to undertake reference model studies because we believe they provide invaluable perspectives into the damaged sites that restorationists work with and, more importantly, insights into how that damage may be reversed. We saw little discussion of this subject in ecological restoration literature, but were able to draw from other sources—anthropology, archaeology, ecology, historical geography, physics, and others—where dialogues about the history of the interaction between humans and the environment, and the importance of studying initial conditions, have been underway for some time. It was from our realization of this important need that this book was born.

To begin the preface to this new Island Press/Society for Ecological Restoration International edition, I would like to expand more on the methodology involved in a historical study of the ecology of a damaged site. To do so, I want to use my history with the book itself as an example of the shortcomings of single-source information and then examine the importance of developing a cross-referential, interdisciplinary reference narrative.

I have no recollection of when I first started thinking about this book—sometime in the early 1990s, I suspect. The first hard evidence I have of my involvement is a letter in my files dated August 18, 1993, from Alan Crowden, then of Cambridge University Press, in which Alan described a conversation we had about the idea of a book on landscape analysis. As I recall, our conversation took place during the Ecological Society of America meeting in Madison earlier that month. I remember being pleasantly amazed that someone of Alan’s stature in the publishing world would be interested in my idea. In 1994, Stephanie Mills, whom I met while she was doing her book In Service of the Wild: Restoring and Reinhabiting Damaged Land, suggested that I meet Barbara Dean of Island Press at the Society for Ecological Restoration (SER) Conference in East Lansing, Michigan. So, while having dinner with Stephanie and Barbara at the SER awards banquet, we got to talking about my idea about a book that would help restorationists better define reference models for their projects as well as another book about environmental education and ecological restoration. Barbara listened intently and encouraged me to pursue the book about reference models. Shortly thereafter, I began to research the topic whenever I got a chance in between my part-time editing job with Restoration & Management Notes and my ecological restoration consulting work. In 1995, Bill Jordan, Steve Packard, and Connie Mutel recruited me to help with the editing of what turned out to be several chapters in The Tallgrass Restoration Handbook, which was being published by Island Press. While this work postponed my efforts on the reference models book, it was a great and needed learning experience for what lay ahead.

Two years later, at the SER Conference in Ft. Lauderdale, Florida, I met with Barbara and then SER Executive Director Don Falk to further discuss the idea of a book about reference models. At that point, I had a working outline and a list of potential authors. Barbara and Don where very encouraging and gave me the go-ahead. By 1998 the real work began—calling people and asking them to contribute their knowledge to the book, receiving acceptances and rejections, finding new people, searching the Web and University of Wisconsin—Madison libraries for information about historical ecology and its various techniques; historic range of variation, macroecology, and much more. Phone calls, letters, and e-mails flew across the country. Don and Barbara encouraged me to find a reputable ecologist to help with the project and, in early 1998, Evelyn Howell agreed to serve as co-editor of the book. She was a tremendous help. We discussed and critiqued each chapter and made an important contribution of our own with the introductory chapter. By 1999 things were really rolling, although not all the chapters were set. I was encouraged enough, however, by the positive response to the idea to organize an all-day symposium on historical ecology and ecological restoration for the SER Conference in San Francisco. The symposium was a great success and, in doing the work for it, I found two of the missing pieces that I knew the book badly needed—both case studies from the western United States. I also came to know Carole Crumley, editor of Historical Ecology: Culture Knowledge and Changing Landscapes and a recognized leader in historical ecology. Carole flew out to San Francisco from North Carolina on her own nickel and gave a great opening talk at the symposium. She would become my mentor on historical ecology, heterarchy, and complexity theory.

I mailed out the final draft of the book to Island Press on March 1, 2000 and was relieved to have it out of my life at least for a while. I worked during various periods of that year on the index and proofing the corrected page proofs as well as working with the marketing division of Island Press. The book was in my hands in February 2001—a nearly decade-long process was over.

Throughout most of this period, I had conversations with Bill Jordan, my colleague and mentor at the University of Wisconsin-Madison Arboretum, about history, ecological restoration, and many other topics. But there were other important influences, including Carole Crumley, and the writings of philosopher Edward Casey, author of Remembering and Getting Back Into Place; environmental historian William Cronon; historical geographer John Sheail, and macroecologist Jim Brown. I also found support in the ongoing projects of the Land Use History of North America Project, David Foster, Emily Russell, Grace Brush, and many others working in fields outside of ecological restoration. And, of course, there was the never-ending support of Evelyn and Barbara.

What method have I used here to briefly describe the history of my experience in developing and editing The Historical Ecology Handbook? I would describe it as a progressive narrative based on documentation (letters, notes, legal documents, computer files) and my own memory. It is progressive because it moves in time in a linear fashion from the initiation of an idea to its completion. It is a narrative because I have told it as a story complete with actors, action, places, and feelings. Is it complete? No. Is it biased? Yes. Is it an approximation of what happened? I guess. Have I told everything? No, I haven’t given you any of the domestic context I was working in, for example. Or told you what kind of computers and computer programs I used. How could you learn more? Talk with Don, Barbara, Evelyn, and others in the process.

There are several points that I want to make here. First, is the importance of recognizing that by doing historical ecology research you are entering into a dialogue with a place, its people, plants and animals, and its past. Out of this process of uncovering, analyzing, and interpreting cultural and biological data will come a narrative because everything we touch involves us in a history with it, and provides us with the opportunity to create a referential narrative history; if we keep or discover the proper records. This historical information, when combined with analyses of current site conditions or conditions of similar sites, provides the reference or model for future restoration projects. So, in a very real sense, we are harvesting the past to plant the future.

The reference narrative developed by historical ecological research is, as Eric Higgs notes in Nature by Design: People, Natural Processes, and Ecological Restoration, ... a key to this scientific endeavor [ecological restoration] because it provides the evidence on which all measurement and analysis depend (p. 162). But the narrative only really works when, unlike my story above, it is the result of the careful analysis of a multidimensional, multi-sourced set of information that is part of an interactive, self-correcting process. For example, to obtain a more accurate picture of how The Historical Ecology Handbook came to be, you would have to check the records of Island Press, the letters and e-mail correspondence of Barbara Dean with me and others involved, and interview Evelyn Howell and the contributing authors. This new information as well as the information from my story would be re-analyzed to obtain a truer picture of the history of this book. Single-set data, like my records and memory, tend to fade with time and have various spatio-temporal as well as psychological biases. Only by delving deeper and obtaining multiple sources of information and then cross-referencing them can you obtain a complete reference narrative. The restorationist using the techniques in this book should aim to create a factual reference narrative that is as close as possible to a historical biography of the land and its relation to people—not some sort of historical fiction.

My second point is in response to what is arguably the most asked question when the conversation turns to reference models, namely, to what period or time should I restore the site? Evelyn and I feel that rather than asking this question, it is more important to ask what was the historic range of variation in which the ecosystem or some sub-set of it operated when it was biologically diverse and ecologically healthy. The techniques featured in this book will help answer such a question and, we hope, will assist restorationists in planning and implementing objectives that will restore the biological diversity of the damaged site. In the end, it may be best to remember what that great American writer and smart aleck, Mark Twain, is reputed to have said, History doesn’t repeat itself, it rhymes. Historical ecology studies can reveal a pattern—a meter, a range of variation—against which we can strike a resonance with the past. Strictly copying the past is not only impossible when working with dynamic ecological and social systems, it’s not that creative. It’s better to re-create, in the best sense of that term, than to simply copy.

Historical ecology studies serve another important function by helping restorationists recognize and envision time. Sociologist Eviatar Zerubavel, author of Time Maps: Collective Memory and the Social Maps of the Past, suggests there are three basic visions of time—linear, multilinear, and cyclical—and five basic narratives about time—progressive narratives, regressive narratives, zig-zag (rise-and-fall or fall-and-rise) narratives, all of which are unilinear; steps-and-ladders narratives, which are multilinear; and recurrence narratives, which are cyclical.

Environmentalists, it’s pretty safe to argue, employ a regressive narrative. That is, they generally tell the story of some aspect of the environment that is in decline. Sophisticated environmentalist treatises may use the multilinear, steps-and-ladders approach (imagine a cladogram to demonstrate species extinction, for example), but it produces roughly the same effect—pessimism, outrage, and urgent calls for protection. On the other hand, individuals who live close to land—farmers, ranchers and indigenous peoples—use the age-old recurrence narrative of following the seasons and following a defined course of activities through the seasons. In some instances, nature writers, like Aldo Leopold in A Sand County Almanac, have adopted the recurrence or cyclical narrative to great effect.

Restorationists often have some of each of these narratives in their minds when they think about time (indeed, none of these narratives is totally exclusive to the groups I’ve named), but the most likely narrative they employ is fall-and-rise narrative. In this zig-zag narrative, restorationists acknowledge that the regressive narrative of environmentalism has basic truth to it and recognizes the sense of urgency in its message, but because of their belief in their work, they expect the situation to have changed or be changed in a progressive, positive direction. As environmental historian Marcus Hall noted in his 1999 doctoral dissertation, environmental restorationists see a better past alongside a worse present, but with a hopeful future.

What historical ecology studies provide to the restoration narrative is a corrective measure. They put the past and present in focus by measuring the cyclical variations in natural and cultural processes and populations, thereby bringing the recurrence narrative into play and offering a buffer to the despair of the regressive narrative. For example, measuring tree rings to determine fire return intervals, reading pollen diagrams to see changes in species composition over time, or taking soil cores to find the plow layers and other soil disturbances or deposition layers each bring us in touch—really in touch—with how the environment has changed or operated with a range of variation and offers explanations as to why. They give us a connection with the earth and its past that we can make sense of, create a story about, and move forward with. Eric Higgs puts it this way: Restoration practice is valued because of its capacity to show us what historicity means to us (nostalgia), the stories that bind us to place (continuity), and the temporal depth of our affiliations (p. 156).

I would like to wrap-up this preface by discussing what reviewers have said about the book and taking a brief look at the state of reference conditions and ecological restoration. Most of the reviews of The Historical Ecology Handbook were quite positive, which was welcome and I think reflects well on the breadth of topics covered, the authors’ levels of expertise, and the overall attempt to try to bring interdisciplinary study into the practice of ecological restoration. The main criticisms of the book focused on the limited number of case studies and/or the poor relation the case studies had to actual restoration projects. I think this a valid criticism; one that should be remedied by a future volume composed exclusively of case studies that have a strong relationship to restoration projects, and one that has a stronger section on overall methodologies. At the time that this book was being developed, Evelyn and I found very little work of this kind. Moreover, our decision to focus on techniques precluded us from adding more case studies had we found them. A couple of reviewers also pointed out that while Mike Morrison in his chapter on wildlife did discuss working with museum samples of animal bones, eggs and the like, we failed to include a chapter or section on the use of herbarium samples. Obviously, this is an important point and we encourage the use of herbarium samples when doing historical ecology studies related to restoration. Finally, there were mistakes in copyediting and proofreading that found their way, somehow, through the process. We apologize for those errors and have worked to correct them in this edition.

Evelyn and I are pleased that this book has raised the level of awareness about the importance of understanding the history of proposed restoration sites and using that information, along with other referential and modeled data, to set the goals and objectives for a project. The fact that the SER International Primer on Ecological Restoration (v. 2, 2004, SERI Science and Policy Working Group) acknowledges the importance of reference ecosystems as models for the planning and evaluation of restoration projects is a definitive signal of the importance of this book and its message. Second, is the continuing presence of historical ecology projects related to ecological restoration, especially the Historical Ecology Project of the San Francisco Estuary Institute as first described by Robin Grossinger in chapter 17 of this book and more recently on the SFEI Web site at www.sfei.org/HEP/index.html, and the work of the Ecological Restoration Institute in Flagstaff, Arizona, which Peter Friederici has recounted in several publications, including the IP/SERI book, Ecological Restoration of Southwestern Ponderosa Pine Forests. Other projects of note include the Historical Forest Ecology Project in northern British Columbia; Rudi Mattoni and Travis Longcore’s study of the Los Angeles coastal prairie; Ian Rotherham’s work linking history and ecology in the restoration of a heathland in Whamcliffe, England; Daniel Schnieder’s narrative about the importance of backwater lakes along the Illinois River floodplain—an area now being restored by The Nature Conservancy and the U.S. Fish & Wildlife Service; Carol Pesch’s ecological history of the harbor in New Bedford, Massachusetts; the Wildlife Conservation Society’s Mannahatta Project, which is aiming to protect and restore historic wetlands in New York City; and Carole Crumley’s continuing work in Burgundy, France. In addition to these projects, this book has found its way into college classrooms across the United States, where educators have used it to ask the basic questions about how and why we do restoration work.

Several outstanding research questions remain in terms of better linking the practice of historical ecology with that of ecological restoration. These include building improved models for integrating diverse sources of information, and developing a better understanding of ecological variation at multiple scales of time and space.

Evelyn and I want to thank Robin Grossinger and Ruth Askevold at the San Francisco Estuary Institute for providing the image for the new cover. It is one of the many images they have produced for the historical ecology project they have underway. Also, our continuing appreciation goes to the staff at Island Press, especially Barbara Dean and Barbara Youngblood; to the Society for Ecological Restoration International; and to the authors who contributed their time and expertise to make this book a reality. Finally, we thank everyone who has read this book and thought about the importance of history, ecology, and ecological restoration.

Dave Egan

Madison, Wisconsin

June 2005

Introduction

Dave Egan and Evelyn A. Howell

That which has been and that which is to come are not elsewhere—they are not autonomous dimensions independent of the encompassing present in which we dwell. They are, rather, the very depths of this living place—the hidden depth of its distances and the concealed depth on which we stand.

David Abram, The Spell of the Sensuous:

Perception and Language in a More-Than-Human World (1996)

Restoration uses the past not as a goal but as a reference point for the future. If we seek to recreate the temperate forests, tallgrass savannas, or desert communities of centuries past, it is not to turn back the evolutionary clock but to set it ticking again.

Don Falk, "Discovering the Future, Creating the Past:

Some Reflections on Restoration" (1990)

A fundamental aspect of ecosystem restoration is learning how to rediscover the past and bring it forward into the present—to determine what needs to be restored, why it was lost, and how best to make it live again. Unlike the protagonist in Trout Fishing in America (Brautigan 1967), who goes to a wrecking yard and finds a complete, extant trout stream for sale, restorationists must search out the missing, forgotten, and overlooked aspects of the ecosystem they wish to restore and, once they find them, begin to reassemble them into a viable system. This process requires venturing through many doorways, talking with experts in a variety of disciplines, and sifting through countless documents, museum samples, and pollen diagrams. It also means learning to live with uncertanity. Nevertheless, the answers are there—concealed, as David Abram (1996) puts it, in the very depths of this living place.

We hope this book will encourage ecosystem restorationists to look to the past and to those who study the past—historians, archaeologists, paleoecologists—as a means of discovering the reference conditions so important to their own work. To better describe how to make this connection between history and ecology—or, more specifically, between the emerging disciplines of historical ecology and ecosystem restoration—we set about here to answer the following questions: Why should history matter to restoration ecologists? What are historic ecosystems, and why are they needed in restoration ecology? How reliable are historic ecosystems as reference models, and what can we do to make them more reliable? First, however, we will discuss what we mean by historical ecology and ecosystem restoration.

Historical Ecology and Ecosystem Restoration

Historical ecology has been described variously as the interface between ecology and historical geography that undertakes studies of lost or degenerated historic ecosystems (Dirkx 1999), and as a discipline that "traces the ongoing dialectical relations between human acts and acts of nature, made manifest in the landscape" (Crumley 1994, emphasis in original). In general, historical ecologists agree on the following points:

Human influences, ranging from the subtle and benign to the overtly destructive, are pervasive throughout the earth’s ecosystems. Historical ecologists recognize that the present geologic epoch—the Holocene (from ten thousand years ago to the present)—is the age of Homo sapiens living in both sustainable and surplus cultures, and always with some level of technological and ritualistic sophistication (Diamond 1997).

The interaction that takes place between the environment and human cultures is not deterministic, but rather a dynamic dialectic process that results in landscapes, which are, in effect, culturalized ecosystems. These landscapes are the common unit of analysis for historical ecologists because landscapes hold the record of human activity on the earth.

Humans, while pervasive and potentially destructive, especially when their population pressures become too high or when their technology goes unchecked, can produce and help to maintain sustainable, diverse ecosystems.

Despite its emphasis on the past, the work of historical ecologists is future seeking.

Finally, historical ecologists (Sheail 1980; Crumley 1998; Dirkx 1999) look at and interpret changes operating at different scales by using a variety of techniques—many of which will be covered in this book. This last point has recently received support in North America from ecologists (Christensen et al. 1996; Covington et al. 1997) and paleoecologists (Russell 1997; Delcourt and Delcourt 1998; Swetnam, Allen, and Betancourt 1999) who view the use of historical ecology techniques as beneficial to the management of ecosystems.

Historical ecologists and ecosystem restorationists share many ideas and values, although restorationists are interested not only in studying past ecosystems and landscapes, but also in returning them to a semblance of their former being.

A relatively young discipline, ecosystem restoration has many roots—landscape architecture, conservation, reclamation, the science of ecology, environmental mitigation—and a corresponding diversity of approaches and applications. Projects as different as planting former agricultural fields to native grasses to support pheasant populations in the Midwest, revegetating disturbed coastal areas with seagrasses, and planting buffer zones around remnant areas have been called restorations. One of the common themes that emerge from these efforts is the basic human instinct to care (Egan 1988; Oelschlaeger 1994). That is, ecological restoration efforts can be seen as a positive counterbalance to the disruptive effects of modern human activities. This implies a focus on efforts that promote biodiversity and complexity through the protection and restoration of native species and heterogeneous ecosystems.

The theory (restoration ecology [Jordan, Gilpin, and Abers 1987]) and practice (ecological restoration) of ecosystem restoration are, as is befitting a relatively young profession, still in a stage of self-discovery. Theorists and practitioners alike are striving to define the field and to identify a set of unifying principles or concepts—to decide what are the best, most authentic means of restoring what has been damaged or lost. This striving for authenticity brings restorationists face to face with the central role of time and requires that they understand past conditions in order to reestablish the historic processes and components needed to repair damaged ecosystems.

Why Should History Matter to Ecosystem Restorationists?

To examine why ecosystem restorationists should be concerned about history (the record of the passage of time), one needs to understand the procedural theory that grounds the practice of ecosystem restoration. The procedure can best be described as a series of linear steps (box 1.1), although in practice the process is more dynamic and given to coordinated tasks. In essence, the restorationist first develops an accurate pre-modern model of the ecosystem or site and then prepares a prescription that will, within the context of modern restraints, move the system from its existing condition to one that more closely resembles the reference model. This procedure seems simple enough in concept—and is relatively easy to achieve if you are dealing with a mechanism like an old car that needs fixing. Ecosystem restorationists, however, are working with dynamic systems that are constantly changing over time and space, which makes the problem of developing and applying a reference model difficult and infuses it with a level of uncertainty. In order to do this type of work, the old paradigm of nature in balance must be forgotten (Botkin 1990), and the new metaphor of flux of nature (Pickett and Parker 1994) adopted.

Box I.1. Outline of Ecological Restoration Project Procedures (Howell 1999)

A. Carry out preliminary research.

Perform site inventory and analysis.

The key to success in restoration is matching species and environment. Many restorations are dominated by broadly tolerant species perhaps because we have not been careful enough in the match.

Initial conditions greatly influence the direction of vegetation change (colonization, inhibition, facilitation).

Study prototypes (remnants and reports) to develop ecosystem models for the restoration to emulate.

Review reports of previous restoration experiments and projects.

Locate sources of materials.

B. Determine project purpose, site use policy, and research component.

C. Create the planting plan—describe the desired end point and what is to be planted where and when to achieve the end point.

Determine ecosystem restoration goals and objectives based on ecosystem model.

Specify species composition, abundance, distribution patterns

Describe desired community structure

Highlight desired ecological processes

List numbers and proportions of species to be planted (if any).

Choose materials: seed, seedlings, cuttings.

Determine planting techniques.

Specify method

Specify timing

i. Which season?

ii. All at once or in phases?

Specify (or not) locations of individual plants or seed mixes.

D. Prepare the site.

Remove undesirable biota.

Create a good planting medium.

Enhance/ameliorate site conditions.

E. Implement project and research plan.

F. Monitor the site to see if objectives are being met.

If so, continue as planned.

If not, make mid-course correction.

G. Prepare restoration plan for animals, insects, etc.

H. Manage the site

Discourage pests.

Maintain natural processes.

Typically, there are two ways to develop such a reference model: (1) by studying the body of theory that concerns itself with the nature of ecosystems; and (2) by acquiring information about the composition, function, and structure of ecosystems in the past and present. Both ways are essential to make the model accurate because, as Pickett and Parker (1994) write, Although sound ecological generalizations and predictions arise from regularities in species characteristics, environmental properties, and the interaction of species with one another and with physical environments, the specific dynamics of any one system will be contingent on its history, the accidents of arrival of species at the site, and the nature of the system’s connections to the surrounding landscape.

Finally, and from a different perspective, developing a history of this type—one that emphasizes the human recording of both human and nonhuman events—may do more than help the restorationist model the systems that need repair. The involvement of the restorationist in this process of discovery will likely (1) help restorationists locate themselves within the complementary opposition (Whitehead 1998) of culture and nature; (2) provide them with a sense of personal, professional, and bioregional identity; and (3) serve as a guide or reference for present and future action. (Of course, as geographer David Lowenthal [1985] warns, the past can also be used as an escape from an unacceptable present, and its embrace may be viewed as a means to inhibit change, embargo progress, dampen optimism, and stifle creativity.)

What Are Historic Ecosystems and Why Are They Important?

Historic ecosystems are those ecological systems that existed prior to this time. They may have existed several decades to many millennia ago. Historic ecosystems include systems on a continuum from highly cultured landscapes to wilderness areas—systems that may have been influenced or modified by human activities to varying degrees over time. Historic ecosystems are important to restorationists because they can be useful as analogs or guides to current restoration actions.

To better understand why historic ecosystems are important, and to begin to establish a framework for working with the data derived from the techniques described in this book, we now focus our attention on several concepts that ground the use of historic ecosystems as reference systems. These include ideas about complex systems, initial conditions, range of variation, and reference