Restoring North America's Wild Birds: Lessons from Landscape Ecology.—Robert A. Askins. 1999. Yale University Press, New Haven, Connecticut. ISBN 0-300-07967-2. Paper, $30.00.—Anyone questioning why wild birds are “flagships for conservation” will find their answers in this wonderful book. Robert Askins' eyes-wide-open approach to the task set forth in the title is utterly engaging, and, although clearly for people with avian affinities, it is especially relevant for conservation biologists from all walks of life.
Reading Askins' book was like being a student in a field course! In the first nine chapters (of a total of 10), I romped through the major biomes and habitats of North America, looking at each through the eyes of an experienced and impassioned naturalist-ornithologist. In each chapter, Askins focuses on a region's bird species and communities that are declining, at risk of decline or extinction, or are already extinct. Then, he systematically employs foreshadowing to prepare readers for the central lesson that “Conservation of birds depends on a clear understanding of both their habitat requirements and how their habitats are sustained.” To convey the complexities of this truth, Askins builds each focal ecosystem step by step, attending to historical generative processes (biotic and abiotic), presettlement distributions and species composition of the vegetation, as well as key requirements of the bird species at risk. Then, using copious scientific results woven into a pleasing format, Askins explains what features of the system are needed to maintain species at risk, and, in turn, how these features are generated and maintained. Chapter conclusions extend understanding of processes that maintain the habitat in the condition and at the scale needed by the species at risk, to what it will take to protect those processes.
For me, two aspects of Restoring North America's Wild Birds were especially valuable. First, the book destroys certain myths that hinder intelligent bird conservation. The media hype that Neotropical migrants (e.g. wood-warblers) are the only North American songbirds at risk has clouded our professional recognition of other systems in need of scientific study and crisis management, such as grasslands and eastern shrublands. For example, many of us uncritically accept the common perception that the current decline of birds that are characteristic of eastern thickets (e.g. Yellow-breasted Chat [Icteria virens], Brown Thrasher [Toxostoma rufum], Painted Bunting [Passerina ciris]) is not a crisis. If we assume that the eastern seaboard was once a seamless blanket of deciduous forest, we might not opt to manage habitats for those species that enjoyed ephemeral old fields. But Askins lucidly explains how shrublands must have been extensive along the hurricane-battered coasts and oft-flooded riverine corridors in coastal lowlands before European settlement. He points out that coastal and river margins in the East were densely settled before we began accounting for the distributions of shrublands we destroyed, thus challenging the dogma that shrubland birds don't belong in the East owing to their lack of historic existence there.
Second, Askins examines without bias modern human influences on ecosystems and species, therefore encouraging the intellectual means to understand where and how we can fit into a continental scheme of conservation. For example, now that coastal and riverine shrublands are scant in the East, inland old-field communities and some suburban ecosystems serve as refugia for the displaced thicket birds. Askins argues that these habitats should be recognized in regional conservation planning for their ecological roles. Furthermore, the question has been raised as to whether livestock grazing is good or bad for grassland birds. Askins explains how grazing can be both, depending on the nature and history of the ecosystem and the likelihood of its conversion to more destructive land uses. Birds of short-, mixed-, and tallgrass prairie (e.g. Mountain Plover [Charadrius montanus], Dickcissel [Spiza americana], longspurs [Calcarius spp.]) historically coexisted with large-bodied grazers, and they currently exhibit adaptations that facilitate coexistence with cattle. Vast areas of grazing lands, therefore, can help maintain some of the continental grassland bird assemblage. Conversely, bird species of the drier deserts, semidesert grasslands, and wooded streamsides cannot tolerate cattle grazing because cattle destroy the habitat itself. Askins argues that, although not a perfect mimic of native herbivory, contemporary cattle grazing represents a tolerable alternative to crop conversion or human settlement for many grassland areas. This means that rural livelihoods can be appropriately fostered in large-scale conservation planning that can cope with regional differences in ecology.
What are the “Lessons from Landscape Ecology”? Each chapter communicates essential concepts of landscape ecology as part of the “story” of how each system works. For example, the importance of geomorphology and spatiotemporal disturbance regimes in guiding the historic development of ecosystems is featured in every chapter. Askins does not solve all of the mysteries of historic bird distributions, and he does not hold back his opinion when facts are insufficient. But logic is pervasive in his historical scenarios. The shifting mosaic of community structure is an obvious concept once we understand how grassland bird assemblages respond to fire and the spatial dynamics of prairie dog “grazing lawns.” The enormity of spatial scales relevant to bird conservation and the nature of biological connectedness are inherent in our thinking once we understand where Phainopeplas (Phainopepla nitens) spend most of their time in a typical year. When we know the natural history of Red-cockaded Woodpeckers (Picoides borealis), crossbills (Loxia spp.), Brown-headed Cowbirds (Molothrus ater), and the intimacy between pinyon pine and Pinyon Jays (Gymnorhinus cyanocephalus), the evolutionary link between scale, process, and the birth and sustenance of wildlife-habitat relationships becomes tangible. Unlike a textbook, Restoring North America's Wild Birds educates the reader in much the same way as an elaborate and intensive field course in landscape ecology.
The title of the final chapter suggests that the pieces comprising the conceptual framework of landscape ecology, enchantingly explored in preceding chapters, would be riveted together here into more specific guidelines for protecting processes that sustain bird habitats. Instead, the concluding chapter was more general than I expected, beginning with another case study (the Ivory-billed Woodpecker's [Campephilus principalis] demise) to emphasize a basic principle: that the central cause of extinction is loss of large areas of functioning habitat. Arguably, we don't need a new discipline to understand this point! Askins moves on to general themes of restoration, leaving the reader with a practical vision of “cooperative management.” The idea here is that if thinking based on landscape ecology is integrated with human dimensions (e.g. land use economics and policies), we can restore the complex weave of natural landscapes that comprise functioning ecosystems that support our (beloved) native species.
This book is appropriate for all readers with an interest in conservation and/or birds, but the conservation angle is emphasized as the main strength. Because birds are better known biologically than other organisms, a work with similar depth and breadth in community and landscape ecology could not have featured any other taxon. Conservationists dealing with planning at any spatial scale (local, regional, ecosystem management, national, etc.) will find here the kind of insights that spark good ideas for managing ecological communities to favor native species. Although the book is not a procedural manual for conservation, it is clearly more applicable than merely heuristic. I would use this book as recommended reading in undergraduate Landscape Ecology, Conservation Biology, Biogeography, and Wildlife Ecology courses, and as required reading in Avian Ecology and Conservation courses. I will extract parts of it for lectures in my own courses because of its extensive incorporation of scientific findings with relevance to conservation. The book would benefit from an index of concepts (there are taxonomic appendices, chapter notes, and references) to make it more useful in college courses. Ample visuals accentuate the readability; excellent line drawings by Julie Zickefoose and many good photographs enhance the text on most FPAGE, and pithy quotes appear with each chapter heading. Restoring North America's Wild Birds should be available in every kind of library because its relevance to conservation crosses all societal boundaries.