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more extended treatments of the manyissues addressed in Animal Social Com-plexity rather than these relatively brief,data-free presentations, concise andreadable though many may be. The vol-ume could, however, serve as a usefulstarting point for a senior undergradu-ate or graduate seminar, providing use-ful introductions to relevant literaturethat students could consult in preparingoral or written presentations.

BENNETT G. GALEF JR.Department of Psychology

McMaster UniversityHamilton, Ontario L8S 4K1, Canada

Reference citedByrne R, Whiten A, eds. 1988. Machiavellian Intel-

ligence: Social Expertise and the Evolution of In-

tellect in Monkeys, Apes, and Humans.Oxford

(United Kingdom): Clarendon Press.

NOURISHING HUMANS WITHOUT DIMINISHING

NATURE

World Agriculture and the Environ-ment: A Commodity-by-CommodityGuide to Impacts and Practices. JasonClay. Island Press, Washington, DC,2004. 568 pp., illus. $35.00 (ISBN1559633700 paper).

Jason Clay, vice president of WorldWildlife Fund’s Center for Conserva-

tion Innovation and one of the first pur-veyors of “green marketing,” brings toWorld Agriculture and the Environmentdecades of agricultural experience, be-ginning with working the family farmin Missouri. He has synthesized into thisaccessible reader an impressive volume offacts, figures, and trends on the state ofworld agriculture and its myriad envi-ronmental impacts.

Unlike the reams of statistics aggre-gated in national or United Nations Foodand Agriculture Organization reports,the numbers for each of the 21 com-modities covered in Clay’s work are woven into a narrative that captures sig-

nificant patterns. Two trenchant chapterscover “agricultural trends and realities”and “agriculture and the environment.”These are followed by chapters on sepa-rate commodities, each of which beginswith a map of the geographical areas ofproduction; “fast facts” on productionand international trade; the key coun-tries that produce, export, and importthe commodity; and a summary of ma-jor environmental impacts and the po-tential for improvement. Clay examinesin some detail the main threats that eachcommodity poses to the environmentand the overall global trends that shapethese threats. He also presents a detaileddiscussion of best management practices(BMPs), both tried-and-true ones andnew approaches, that could boost pro-duction while minimizing ecologicallosses.

The book can be read from multipleperspectives. For example, Clay exam-ines eight categories of threats and im-pacts—habitat conversion, invasivespecies, agrochemicals, soil erosion,wastes, water, fire, and greenhouse gas(GHG) emissions; he then presents in-novative policy recommendations—some market based, some that operatethrough regulatory enforcement—foraddressing them.

Habitat conversion, especially of intactecosystems with globally significant bio-diversity, is covered quite well. Severalstriking insights run through many ofthe commodity assessments:

� Habitat conversion can occur regardless of whether the com-modity price increases, decreases,or remains stagnant.

� A commodity’s scale of produc-tion in terms of hectares undercultivation may not always be themost meaningful indicator ofbiodiversity threat and impact.

� Advances in biotechnology (bothclassical and transgenic) continueto overcome one agriculturalconstraint after another, enablingexpansion of production intohabitats previously inhibited bysome limiting factor.

� Agricultural subsidies promotehabitat conversion. Ironically,though, the reduction of the Organization for Economic Cooperation and Development’sdomestic manipulation of con-sumer prices and of its provisionof producer subsidies (which to-taled over $300 billion in 2001)could also accelerate conversionof some of the planet’s most bio-logically rich habitats in develop-ing countries. (Such conversioncan be avoided, however, by the use of mechanisms I discussbelow.)

All of these factors combine with othertrends to pose ever-present threats thatlead to broadscale fragmentation, degra-dation, and destruction of intact ecosys-tems. These other trends include anannual increase in human populationgreat enough to people Mexico; as in-comes rise, growth in the percentage ofprotein derived from animals, a shift thatdemands even more agricultural land;conversion of natural resources in de-veloping countries to alleviate masspoverty and foster economic expansion;a rising rate of consumption of land-based commodities globally; and a steadydecline in the quality and productivity ofsoils.

Clay’s most important BMP and pol-icy recommendations to combat suchthreats concern land zoning: Areas ofhigh biodiversity and habitats importantfor maintenance of ecosystem servicesshould be set aside, he maintains. Notonly does such zoning need to be done atthe landscape or ecosystem level, he says,but it is essential to identify minimal-size, viable forest fragments of biologicalsignificance within commodity opera-tions.

“Farming with nature,”an idea long ig-nored by large-scale, high-input mono-culture systems, is attracting greaterattention. The concept ranges from con-necting fragmented patches into ecolog-ical corridors for sustaining viablepopulations of endangered species (e.g.,Sumatran rhinoceroses in unplanted areas of oil palm plantations) to usingmulticrop systems with ecologically based

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pest-management strategies (e.g., shade-grown coffee and cocoa).

Regenerating degraded and aban-doned lands is another critical recom-mendation for slowing deforestation,which averaged 15 million hectares perannum over the past decade. One-fourthof the world’s agricultural land area isdegraded, much of it capable of beingrevitalized for production. Brazil offers acase in point. Sixty million hectares arecurrently under production in that coun-try, with another million hectares offorests being converted into agriculturallands each year. Meanwhile, 80 millionhectares of land lie abandoned or degraded. Yet degraded pasture can beconverted into productive soybean–corn–cotton rotations within six years usingno-till practices that augment the soil’sorganic matter. The degraded land is val-ued at $500 or less per hectare, whileland for soybeans is worth $2000 perhectare. Reclaiming degraded land canboost producer assets by up to $300 perhectare per annum over the six years ittakes for regeneration, increasing thevalue of the degraded land more thanthe net value of the soybeans or othercrops produced on it.

As Clay notes,“if even 15 percent couldbe reclaimed for agricultural use, Brazil’scurrent rate of agricultural expansioncould be sustained for twenty years with-out needing to clear a single hectare ofnatural habitat. If productivity is in-creased on each hectare, then the rate ofexpansion of cultivated land could beslowed even more and total productionwould still increase.”

World agriculture is responsible for asizable fraction of GHG emissions, themajor constituent of which is carbondioxide (CO

2). Clay identifies climate

mitigation projects for protecting andrestoring land carbon as potential sourcesof income to fund many of the BMPsand land zoning policies.According to theIntergovernmental Panel on ClimateChange, the equivalent of 360 billiontons of CO

2could be captured in the

next five decades through prevention ofdeforestation, restoration of fragmentedlandscapes, and agricultural and forestrysequestration. Although this amount isonly 10 percent of the total reduction in

GHG emissions that may be needed thiscentury to stabilize atmospheric con-centrations, it represents a potential income of many hundreds of billions of dollars for these climate mitigationservices, which could simultaneouslybring biodiversity benefits and help trans-form impoverished rural communitiesinto ones with sustainable livelihoods.For example, Brazilian scientists haveproposed a national cap on Amazoniantropical deforestation, which averaged 2 million hectares per year over the pastdecade. If the national loss were thenfurther reduced, say, 10 percent belowthe cap, or 200,000 hectares per year, thiswould prevent the release of more than50 million tons of CO

2. These saved tons

could then be sold to countries and cor-porations that need to reduce their CO

2emissions, accruing revenues in excessof $150 million per year (at current lowprices of $3 per ton of CO

2).

Storing carbon is but one among sev-eral environmental services that, Clay ar-gues, provide important societal benefitsand economic value. Others are main-taining watershed quality and quantity,protecting biodiversity, and preventingsoil erosion. Payments to farmers to helpsustain and restore these services, Claysays, are justifiable.

Is it reasonable to think that in timesof shrinking government budgets andrising national debts such new fundswill be forthcoming? Clay answers affir-matively, proposing that some of thehundreds of billions of dollars per yearof production, export, input, credit,and infrastructure subsidies be shiftedinto paying for environmental services“beneficial to all members of society,both for this generation as well as forfuture ones.” The rest of the subsidiesand other market barriers should thenbe phased out.

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Clay acknowledges that the politicalclout of producers and the legitimateneed of society to ensure adequatefood and fiber supplies pose formid-able barriers to eliminating subsidiesin the near term. Such inertia, how-ever, is being challenged by a world-wide counter-trend to remove market-distorting policies.

A large part of World Agriculture andthe Environment focuses on BMPs thatimprove farm operations, reduce eco-logical impacts, and increase bio-diversity benefits, thereby achievingmonetary savings and productivitygains. Clay makes three key recommen-dations: (1) Promote socially respon-sible and equity-based BMPs (e.g.,worker incentive programs, employeestock option plans); (2) make BMPs the basis for regulatory structures and permitting systems; and (3) base invest-

ment, insurance, and purchase screenson BMPs. He also discusses the cur-rent shortcomings of “eco-labels” andcalls for improvement of certificationsystems.

Overall, Clay’s commodity-by-commodity guide is a rich referenceworthy of inclusion in any library, andit will inspire readers to delve moredeeply into this provocative and impor-tant topic. The book certainly deservesa wide readership, given that agricul-ture’s overall impact on the planet’secosystems is greater than that of anyother human activity.

MICHAEL TOTTENConservation International

Center for Environmental Leadership in Business

1919 M Street, NWWashington, DC 20036

UNCERTAINTIES IN RIVERRESTORATION

Strategies for Restoring River Ecosys-tems: Sources of Variability andUncertainty in Natural and ManagedSystems. Robert C. Wissmar and PeterA. Bisson, eds. American Fisheries Soci-ety, Bethesda, MD, 2003. 283 pp., illus.$69.00 (ISBN 1888569468 paper).

In a special issue of BioScience in 1995entitled “Ecology of Large Rivers,”John-

son and colleagues (1995) pointed out intheir introductory article that a numberof useful concepts had been developed tounderstand the interactions betweenphysical and biological factors in largeriver systems. They also highlighted thefact that these concepts failed to recognizethe importance of nested scales of inter-actions, both spatial and temporal,between large-scale processes (such asclimate change and tectonic factors) andsmaller-scale processes (such as in-traspecies and river flow–species inter-actions). The authors additionally statedthat “better methods and tools areneeded...to predict a river’s physical andbiological characteristics along its length.”The authors were absolutely right onboth counts, and that issue of BioSciencewas for me an important landmark in thepromotion of more holistic and con-nected thinking about what we mightaspire to achieve in river restoration andhow we could approach it.

Of course, it is now clear that predict-ing physical and biological characteristicsalong a river’s length is not just diffi-cult—it is, in absolute terms, impossi-ble.And yet predictability is exactly whatriver restorers would like. The reasonpredictability will remain the elusive HolyGrail is the subject of this very timelyvolume edited by Robert Wissmar andPeter Bisson. In Strategies for RestoringRiver Ecosystems, a series of well-editedchapters run the gamut, from sources ofvariability in climate change and all itsknock-on effects into hydrological andgeomorphological patterns, throughsources of variability in riparian and

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