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A Single Avian Conservation Theme, Three Distinct Flight Paths

2012; Wiley; Volume: 26; Issue: 1 Linguagem: Inglês

10.1111/j.1523-1739.2011.01809.x

1523-1739

David C. Oren,

Species Distribution and Climate Change

The American Bird Conservancy Guide to Bird Conservation . D. J. Lebbin, M. J. Parr, and G. H. Fenwick . 2010 . The University of Chicago Press , Chicago , IL . 456 pp. $45 (hardcover). ISBN 978-0-226-664-7272 . Atlas of Rare Birds . D. Couzens 2010 . The MIT Press , Cambridge , MA . 240 pp. $29.95 (hardcover). ISBN 978-0-262-01517-2 . Facing Extinction. The World's Rarest Birds and the Race to Save Them . P. F. Donald, N. J. Collar, S. J. Marsden, and D. J. Pain . 2010 . T & AD Poyser , London , U.K. 312 pp. $72 (hardcover). ISBN 978-0-7136-7021-9 . Endangered species have been a focus of the conservation movement since its inception. Long before anyone heard of the dangers of indiscriminate use of pesticides, much less climate change or the expression human footprint, many were worried about the reckless use of natural resources that drove once abundant species to the point of extinction. Initially, attention focused on unsustainable harvest of economically important species. Legal actions in the United States promoted by conservationists date back to at least 1870, when the U.S. Congress adopted legislation to limit the period during which Northern fur seals (Callorhinus ursinus) in Alaska could be taken. As much as the conservation agenda has expanded, endangered species continue to be a compelling issue that has gone far beyond unsustainable harvest of particular species to concern for the full gamut of creation. Perhaps no group is better suited to serve as a surrogate of the biota than birds, the class of organisms whose biology is best known. They have been a central focus of conservation attention since the 19th century, initially because of unsustainable harvest for food and feathers. Outraged ornithologists and the general populace alike promoted the founding of the American Ornithologists’ Union (1883) and National Audubon Society (1895). Their actions led to the establishment of the Migratory Bird Treaty Act (1918). The American Bird Conservancy Guide to Bird Conservation is an excellent reference on the status of endangered bird species of the United States, a guide to the major types of bird habitat, and a call for conservation action. The book should be considered a new standard reference for these and other topics it covers, in particular its evaluation of habitats and comprehensive analysis of threats. In the introduction the authors discuss motivations to conserve birds; changes in bird populations; tracking bird declines; ranking threats to bird populations; the history and future of bird conservation in the Americas; and setting priorities for species, places, and threat abatement. Following the introduction is a species-by-species account of the 210 species on the 2007 American Bird Conservancy WatchList (Butcher et al. 2007). For each species the authors provide common and scientific names; global population estimate; percentage of the population in the United States; population trend; WatchList status (red, “highest national concern,” or yellow, “declining” or “rare”); U.S. Endangered Species Act status, if listed; WatchList combined score (sum of assessments of population size, range size, threats, and population trend); significant threats; conservation actions underway; priority actions needed; and a map of the species’ global distribution. All this information and a handsome illustration by Chris Vest are presented on half a page. The authors divide bird habitats in North America and Hawaii into 1 human-made and 11 natural “birdscapes,” which in turn are composed of 38 bird conservation regions (BCRs) as defined by similarity of habitats and bird communities within them and by collaborative conservation opportunities. Each of the 12 birdscapes is introduced with a two-page landscape painting by Vest that is cleverly designed to include its characteristic bird species, vegetation, and threats. Each birdscape is characterized by area; BCR codes (defined by the North American Bird Conservation Initiative and numbering 1 to 67); number of WatchList red and yellow species; habitats; condition and threat level for each habitat; conservation actions underway; proposed actions; and location of “important bird areas” (BirdLife International) for each BCR. Maps of each birdscape are provided. The authors review threats from habitat loss; invasive and highly abundant bird species; mortality because of collisions with buildings and glass, communication towers, wind turbines, and power lines; harvest and persecution; fisheries (waterbird mortality associated with longlines and gillnets and shorebird declines related to unsustainable harvest of horseshoe crabs [Limulus polyphemus] for bait); effects of toxins; and effects of climate change. The text on each threat includes sections on problems, solutions, and proposed actions. A table shows that over half a billion native birds are killed each year by feral and pet cats (a figure hotly contested by well-meaning but mistaken ailurophiles) and that an estimated 100 million–1 billion die in collisions with buildings or glass. “Strategies and Actions” outlines the American Bird Conservancy's Strategic Bird Conservation Framework: threat elimination helps all birds, WatchList species need particular actions to conserve their habitat, and endangered species require more directed actions to prevent extinction. “International Bird Conservation” addresses issues in the Western Hemisphere south of the Rio Grande and follows the structure of the chapters on U.S. birds. This is the only chapter I would characterize as oversimplified. In addition, it suffers from a biased U.S. perspective. Atlas of Rare Birds and Facing Extinction are both published for BirdLife International, the largest global alliance of bird conservation organizations. The books overlap in the species treated and both boast handsome maps and photographs, but otherwise could not be more different. The Atlas of Rare Birds has 10 chapters, and each covers five species, ranging from the California Condor (Gymnogyps californianus) and Kakapo (Strigops habroptila) to the Northern Bald Ibis (Geronticus eremite) and Kirtland's Warbler (Dendroica kirtlandii). The often lavishly illustrated species accounts (the glorious Ultramarine Lorikeet [Vini ultramarine] photograph alone is worth the price of the book) are limited to four pages with a map and text on behavior, habitats, threats, and brief history of discovery, decline, and conservation efforts. Author Couzens pulls no punches, and when he believes he should direct scorn toward governments, such as those of Grenada, the United States, and Thailand for failing to conserve the Grenada Dove (Leptotila wellsi), Hawaiian Po’ouli (Melamprosops phaeosoma), and Gurney's Pitta (Pitta gurneyi), respectively, he performs the task with relish. The book appears to be aimed at readers who love birds, worry about humanity's role in the current global wave of extinctions, and might be brought more directly into the conservation fold. It fulfills that role admirably, although more demanding readers will find it short on science and references (32 in the bibliography). In contrast, Facing Extinction is a veritable treasure trove for even the most exacting biologist. It is fluent and authoritative (approximately 1200 references), didactic and some of the 20 chapters that provide species accounts read such as gripping whodunits. The six main sections (“The Nature of Rarity and the Rarity of Nature,”“The Distribution and Causes of Rarity,”“Rarity and Extinction on Islands,”“Saving the World's Rarest Birds; The Lost and the Found,” and “Rarity and Extinction in the Future”) are divided into 26 chapters. There is a fine brief on Allee effects (the smaller a species’ population becomes, the greater the probability its abundance will decrease further [Berec et al. 2006]). Chapter 24 on India's Forest Owlet (Heteroglaux blewitti) is typical of the species accounts. To tell the tale of the bird, it features a cast of human characters, including the intrepid (Pamela Rasmussen, Ben King, and David Abbott), admired scholars (Salim Ali and Dillon Ripley), a historical visionary (Allan O. Hume), and a complicated, deceiving scoundrel (Richard Meinertzhagen). The book is a joy to read and should be on the shelf of every conservationist, ornithologist, or historian of science. Because birds are easy to observe and inspire hordes of amateurs as well as scientists, the data set on them is one of the most complete, which encourages use of those data to represent biological diversity as a whole. The debate on whether the use of any one group as a surrogate for conservation planning is appropriate is still hot among scientists (reviewed by Rodrigues & Brooks 2007). Data sets on birds, because birds are easy to census, sensitive and responsive to environmental change, and mobile, will continue to be used for conservation planning in the face of incomplete knowledge. Regardless of the outcome of the academic debate, guidelines for bird conservation, such as the American Bird Conservancy's Strategic Bird Conservation Framework, that focus on threat abatement, habitat conservation, and specific actions to protect endangered species will also improve the situation for other taxonomic groups, including those that remain uncataloged.