biological diversity in agriculture and global change

EG35CH06-Zimmerer ARI 13 September 2010 12:46

Biological Diversityin Agriculture andGlobal ChangeKarl S. ZimmererDepartment of Geography, Earth and Environmental Systems Institute, Pennsylvania StateUniversity, University Park, Pennsylvania 16802; email: [email protected]

Annu. Rev. Environ. Resour. 2010. 35:137–66

The Annual Review of Environment and Resourcesis online at environ.annualreviews.org

This article’s doi:10.1146/annurev-environ-040309-113840

Copyright c© 2010 by Annual Reviews.All rights reserved

1543-5938/10/1121-0137$20.00

Key Words

adaptation, agrobiodiversity, agroecosystem, climate change, globalchange, globalization

Abstract

Biological diversity of agriculture consists of several analytic levels andspatial management scales that are subject to complex interactions withglobal change. The complexity of interactions is related to the bidi-rectional impacts and influences of global land use and climate changein combination with social-environmental shifts (globalization of agri-cultural development; market integration; technological change; andregulation through global treaties, policies, and institutions). This arti-cle develops a conceptual framework of the complexity of interactionsusing four thematic nodes—biological diversity in agriculture; globalchange; management and scale; and social-environmental adaptation,vulnerability, and resilience. It argues for the increased relevance ofthis framework. Linking expanded scientific research and policy to thisgroup of conceptual nodes yields insight into the impacts of globalchange on biological diversity in agriculture and into the design ofconservation strategies, monitoring approaches, and sustainability poli-cies. Future policy must anticipate interactions of biological diversity,agroecosystem complexity, and global change stemming from the ac-celeration and integration of region-scale land-use intensification anddisintensification.

137

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Contents

INTRODUCTION . . . . . . . . . . . . . . . . . . 138CONCEPTS AND

CHARACTERISTICS . . . . . . . . . . . . 138Biological Diversity in Agriculture . . 139Global Change . . . . . . . . . . . . . . . . . . . . 139

BIODIVERSITY INAGRICULTURE: ANALYTICLEVELS . . . . . . . . . . . . . . . . . . . . . . . . . . 140Variety, Species, and Genetic

Resources . . . . . . . . . . . . . . . . . . . . . . 142Agroecosystem, Landscape,

and Higher-Order Levels . . . . . . . 143MANAGEMENT AND

SOCIAL-ENVIRONMENTALSCALING . . . . . . . . . . . . . . . . . . . . . . . . 144Field and Farm . . . . . . . . . . . . . . . . . . . . 145Community, Multicommunity,

and Large-Area Scales . . . . . . . . . . . 146GLOBAL CHANGE FACTORS

AND PROCESSES. . . . . . . . . . . . . . . . 146Land Use, Climate, and Water . . . . . 146Agroecosystems, Soils, and

Nutrients . . . . . . . . . . . . . . . . . . . . . . . 148SOCIAL-ENVIRONMENTAL

INTERACTIONS . . . . . . . . . . . . . . . . 149Adaptive Capacity . . . . . . . . . . . . . . . . . . 150Globalization and Development . . . . 150Agricultural Intensification,

Disintensification, and FoodSecurity . . . . . . . . . . . . . . . . . . . . . . . . 151

Technology Change . . . . . . . . . . . . . . . 152Global Policy and Institutions . . . . . . 153

CONSERVATION ASSESSMENTAND MONITORING . . . . . . . . . . . . 153Conservation and Sustainability . . . . . 154Reduction, Loss, and Extinction . . . . 155Monitoring . . . . . . . . . . . . . . . . . . . . . . . . 155

CONCLUSION . . . . . . . . . . . . . . . . . . . . . 156

INTRODUCTION

Biological diversity in agriculture is subject tocomplex interactions with global change. Thisbiological diversity is situated at the centerof global land-use transitions and varied types

of social-environmental globalization rangingfrom agricultural and labor market integrationand technology change to the role of globalpolicies and institutions (1, 2). It has becomea focus of potential responses to projectedchanges in regional temperature and precipi-tation regimes amid the anticipated global av-erage warming of land surfaces of 2–3◦C ormore this century (3–5). Human managementis integral to the role of biological diversity inagriculture during these changes. It yields foodand other crop and livestock products meet-ing myriad human economic, social, cultural,and psychological needs. Although an estimated60% of overall caloric consumption is now fur-nished through rice, wheat, and maize (6), hu-mans still manage thousands of useful plantand animal food species and varieties in theirfarm landscapes. Biologically complex and di-verse agroecosystems are part of global agricul-tural land use, covering an estimated 33–38%of the earth’s land surface (7). Both human-social management for food production (andother agricultural purposing) and overarchingland and resource use exert wide-ranging influ-ence on the global change interactions of bio-logical diversity in agriculture. The importanceof these increasingly vital interactions has led toincreased policy interest, political concern, andgrowing public awareness.

CONCEPTS ANDCHARACTERISTICS

A core set of concepts and defining charac-teristics are needed in order to begin to ad-dress the diverse and often complex relationsbetween the biological diversity of agricul-ture and the processes and patterns of globalchange. These concepts include the integralrole of human management and spatial scale.They also include an important and rapidlyexpanding group of concepts focused specifi-cally on biodiversity and ecological dynamicsin agriculture per se. The final sets of con-cepts are ones dealing with global environmentchanges and with the human-environmentaland social-ecological interactions. This article

138 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


provides a framework for linking these diverseconcepts.

Biological Diversity in Agriculture

The concept of biodiversity in agriculture in-corporates all plant, animal, and microorgan-isms existing and interacting in broadly de-fined cultivated environments. It resembles theconcept of uncultivated or wild biodiversity inbridging taxonomic, ecological, and spatial di-mensions and, also, serves as a modulator of abi-otic and ecosystem processes, rather than eitherpurely a determinant or outcome (8, 9). Therole of human management adds a related yetdistinct emphasis in considering biodiversity inagriculture (10). Analytic levels vary from ge-netic resources and biotic elements of targetedmanagement (e.g., crop varieties and species)to agroecosystem and landscape-level functionsand structures, as described in the followingsection. The integral role of characteristic spa-tial scales—ranging from fields and farms tolarger areas—is another consequence of humanmanagement influencing the biological diver-sity of agriculture. One component of biolog-ical diversity in agriculture is planned, whichrefers to the plants and animals subject to delib-erate incorporation and specific management(e.g., crop varieties and livestock breeds). Theother component, referred to as “associated”biological diversity, consists of indirectly man-aged organisms, including pollinators, weeds,soil organisms, pests, and disease pathogens aswell as natural enemies (11–13).

Several key concepts are useful for situatingbiological diversity in agriculture in relation toglobal change. Genetic resources, which referto the genetic diversity of domesticated speciesand their wild relatives, are conceptualized bothas inputs to scientific breeding of new modernagricultural varieties and as a presumed foun-dation of adaptation to global changes (14, 15).Agrobiodiversity is a concept defined as speciesand varieties of crops and livestock and theirwild relatives, including weeds and interactingbiota, modified through the ongoing processof farmer-based domestication and adaptation

Global change:interactions of theearth’s biogeophysicalsystems with humanactivities (such as landuse; climate, water, andnutrient changes; andsocial and economicglobalization)

Globalization: thefunctional integrationof internationallydispersed activities andflows of humans, theirproducts, ornonhumanbiogeophysical factors

Agroecosystem: thespatially boundedcomplex ofagroecologicalstructures andfunctions that includeresponses to bothhuman-inducedchanges andnonhumandisturbances

Genetic resources:the molecular andgenetic-level diversityof domesticatedspecies and their wildrelatives

Adaptation: theprocess of adjusting tochange; it depends onthe sustainability-enhancing capacity ofindividuals and socialgroups

Agrobiodiversity:domesticatedorganisms andinteracting biota inongoing farmer- andland-user-baseddomestication andadaptation

(16, 17). Agrodiversity refers to managementby farmers and land users of the environmentalvariation—both spatial and temporal—of theiragriculture and land use, involving biotic aswell as abiotic resources (e.g., water and irriga-tion management) (18–20). Agroecology is anapproach focused on the interactions and func-tioning of biological, environmental, and man-agement factors and deals with topics such aspest management, intercropping (simultaneousproduction of two or more crops), agroforestry,and environmental change (11). The concept ofagroecosystem refers to the spatially boundedcomplex of agroecological functions and struc-tures, including responses to change (13, 21,22). Genetic resources, agrobiodiversity, andagrodiversity concepts tend to emphasize theplanned subcomponent of biological diversityin agriculture. Emphasis on the associated com-ponent is characteristic of the agroecology andagroecosystem concepts. Domestication, whichis “accelerated and human-induced evolution,”pertains to the planned subcomponent whendirected at individual organisms and progeny,including tree domesticates (23, p. 102; seealso 24, 25). Domestication is also applied toagroecosystems and landscapes, such as do-mesticated forests (26), and thus the associatedsubcomponent of biological diversity in agri-culture. Recently scientific research utilizingthe above concepts has expanded prodigiouslyin major topical subfields (Figure 1, see colorinsert), as has development of these conceptsin policy and applied projects and programs.

Global Change

Global change refers to interactions of theearth’s biogeophysical systems with human ac-tivities (27). Primary interactions of the bio-logical diversity of agriculture are linked tocertain global factors and processes involvingland-use, climate, water, and nutrient changes(28). Land-use conversion aggregated to largeareas also is a form of global change directlyrelevant to agriculture (1, 29). It has occurredat a high rate in recent decades, especially inAsia and Latin America. A pair of interactions

www.annualreviews.org • Agrobiodiversity and Global Change 139

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Agrodiversity: refersto management byfarmers and land usersof environmentalvariation for theiragriculture and landuse

Agroecology: anapproach focused onimproving ecologicalinteractions andfunctioning ofagronomic,environmental, andmanagement factors infarming

Agriculturalintensification: theincreased use of inputs,or yield of outputs, perdesignated unit (e.g.,land area) withinagricultural andland-use systems

along the continua of global agricultural sys-tems is worth noting prior to the main sec-tions below. Agriculture with lesser biologi-cal diversity, even single-species monocultures,may possibly be resilient owing to high-levelresource capabilities among these producers,while the expansion of monocultural produc-tion technologies can exert substantial negativeimpacts on global change through deforestationand the misuse of fertilizers and other agro-chemicals. By contrast, agroecosystems withhigher levels of biological diversity are poten-tially more resilient, whereas actual adaptive ca-pacity in such production is often limited be-cause of vulnerability-related limitations, suchas poverty and limited resource access.

Global change relevant to biological diver-sity in agriculture is a function also of broadlydefined social-environmental globalization.It is propelled through such drivers as globalagricultural trade agreements aimed at the in-tegration of production and commodity chains;technology transfer and diffusion; and globalsustainability conservation strategies, accords,and institutions. These sorts of global social-environmental change are often related directlyin development policies, livelihood issues, andfood security and nutrition concerns. Globallywidespread case studies are incorporated in thisarticle’s analysis to reflect the worldwide scopeof the distributions and dynamics controllingbiological diversity in agriculture (Figure 2).These examples cover the spectrum of agri-cultural resource endowments and technologyranging from high-input/intensity systemsto low-input/intensity systems. Intensity andintensification, which are estimated as thelevel and changing rate of inputs per unitarea, are pivotal concepts vitally important tounderstanding influential trajectories related tobiological diversity and ecological processes inagriculture (30, 31). The impacts of immediateinteractions of the biological diversity ofagriculture with agricultural intensification—feedbacks in a sense—are guided throughsuch social-environmental capacities andconditions as adaptation, coping, resilience,and vulnerability.

This article identifies the role of inter-connections among four groups of concepts:analytic levels of biological diversity in agri-culture; farm and land-use management andscale; global change factors and processes; andsocial-environmental adaptations, mitigation,resilience, and vulnerability (Figure 3). Signif-icant focus of research and policy has tendedto cluster at each individual node and amongcertain couplings. Recent scientific researchand policy making on the biological diversity ofagriculture suggest growing interest in inter-action effects across the four conceptual nodes(Figure 3). This article formulates the fullframework of these nodes to evaluate researchand policy, with special reference to globalchange impacts, sustainability, and conserva-tion design and monitoring involving biologicaldiversity in agriculture. The conclusion belowspecifies the pressing need for future policies toanticipate interactions of the biological diver-sity of agroecosystems and the processes andpatterns of global change. It highlights the in-creased impacts and influence of land-use inten-sification, disintensification, and the increasedintegration of these contrasting transitions.

BIODIVERSITY INAGRICULTURE: ANALYTICLEVELS

Several levels of analysis are needed to de-scribe the biodiversity of agriculture and mustserve as a foundation for understanding its re-lation to global change. Some levels—such asgenetic, variety/breed, and species—are basedon molecular, agronomic, and taxonomic crite-ria, as described below. These levels are nec-essary to describe the scope and magnitude ofbiological diversity and adaptive capacity inagriculture. Such descriptions need to be sit-uated along the spectrum of farm types andin the context of global change that governsagricultural transitions. Other levels are basedon system-type distinctions (agroecosystem,landscape, region, national, international, andglobal) that are not explicitly spatial, whereasthe section Agroecosystem, Landscape, and

140 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Mex

ico/

Cent

ral

Am

eric

a/Ca

ribb

ean

(n=3

2)18

, 24,

34,

36,

37,

38,

45,

55

, 65,

72,

80,

84,

86,

87,

89

, 90,

93,

95,

106

, 114

,13

0, 1

31, 1

32, 1

33, 1

34,

139,

145

, 146

, 147

, 148

, 16

0, 1

63

Am

azon

/Bra

zil

(n=7

) 44,

47,

48,

49

, 58,

60,

165

And

es (n

=8)

41, 6

1, 7

8, 8

1,

82, 8

8, 9

2, 9

6

East

Afr

ica/

Ethi

opia

(n=2

)12

6, 1

38

Euro

pe (n

=6)

59, 6

8, 7

9, 1

35,

143,

166

In

dia/

Nep

al (n

=1)

164

N. A

mer

ica

(n=2

)13

9, 1

40

Aus

tral

ia, O

cean

ia,

S. P

acifi

c (n

=1)

62No

Spec

ific

Regi

on

(n=9

9)

Wes

t Afr

ica

(n=6

)23

, 25,

53,

57,

93,

126

(1) M

exic

o-G

uate

mal

a, (2

) Per

u-Ec

uado

r-Bo

livia

, (2A

) Sou

ther

n Ch

ile, (

2B) S

outh

ern

Braz

il, (3

) Med

iterr

anea

n,

(4) M

iddl

e Ea

st, (

5) E

thio

pia,

(6) C

entr

al A

sia,

(7) I

ndo-

Burm

a, (7

A) S

iam

-Mal

aya-

Java

, (8)

Chi

na.

Sout

heas

t Asi

a (n

=3)

50, 1

01, 1

42

Chin

a (n

=2)

101,

166

N. A

fric

a (n

=1) 1

41

Figu

re2

Wor

ldM

ap,m

odifi

edfr

omV

avilo

v(1

77,p

.430

),w

ithlo

catio

nsof

regi

onal

and

loca

le-b

ased

rese

arch

(use

dan

dci

ted

inth

isar

ticle

).


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Agricultural Management and Scale

Global Change(Land Use, Climate,

Globalization)

Biological Diversity in Agriculture

AdaptationVulnerability

Resilience

Figure 3Conceptual framework of the interactions of biological diversity in agriculturewith global change.

Higher-Order Levels deals with specific spatialscales.

Variety, Species, and GeneticResources

Biodiversity in agriculture is distinguishedin multiple ways, for example, by genetics,variety or breed, species, agroecosystem, andlandscape. Regional, national, continental, andglobal levels are also commonly used. Farmercrop varieties, and correspondingly local animalbreeds, comprise the level most often directlytargeted in specific farmer and land-userpractices and thus the planned managementof biological diversity in agriculture. Thesepractices include scientific production and dis-tribution of modern varieties and breeds. Alsoencompassed are the biologically and geneti-cally diverse types known as landraces, farmervarieties, and local breeds, which are managedin farmers’ own breeding selection and dis-semination. The latter types are maintained infarmer land use and seed practices. They arealso referred to as primitive, ancestral, or folktypes (17, 32, 33). Crop landraces are composedof the seed lots of multiple farmers (34–36).Evolution and ecology of farmer varieties,landraces, and local breeds draw on multi-dimensional influences, ranging from localskills, nomenclature, and nonmarket values to

embedded social relations and cultural knowl-edge (37–41).

Landraces, farmer varieties, and local breedsare still produced in many agroecosystemsworldwide, notwithstanding their significantreduction and loss—described in this arti-cle’s penultimate section. Most producers aresmall-scale farmers and land users, or small-holders, whose cultivated land is estimated tocomprise between one-third and one-half ofglobal agricultural area (19, 32, 39, 42–44).Units designated at this taxonomic level arethe mainstays of in situ conservation strate-gies as well as the chief targets for storage inex situ conservation—also described below inthe penultimate section. Ecological and biogeo-graphic characteristics influence the adaptivecapacity of individual taxa at this level in re-sponse to global environmental change factors,primarily climate characteristics and soil qual-ity. Farmers’ management of biological diver-sity in these varieties and landraces exerts eitherstabilizing selection pressure as reinforcementof genetic cohesiveness or directional pressureand evolutionary innovation, such as purpose-ful hybridization and generation of new types(45).

The biological diversity of agriculture at thespecies level consists of both planned and un-planned components. Species are subject to ahigh level of planned management in scientificbreeding and in the continua of monoculturesand multispecies agriculture (11, 13, 40, 46).Recognition and management of species diver-sity is integral to intercropping (also referredto as mixed-cropping or multispecies agricul-ture), agroforestry, and agropastoral systems ofland use. For example, the species level is acornerstone of estimating the biological diver-sity of useful plants of home garden agricultureand agroforests, especially in tropical and sub-tropical regions, where multiple woody, peren-nial, and herbaceous taxa, along with livestock,are combined in the managed area (44, 47–50).Diverse agroecosystems commonly show highlevels of species richness per unit of cultivatedarea. The species level is also central to estimat-ing the biological diversity of insects, weeds,

142 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


and soil organisms in agroecosystems. Assess-ing this diversity requires distinguishing func-tional species groups and guild ranks withinbiotic communities (12, 51, 52). Phylogeneticdiversity is useful in ascertaining species-richcomplexes vital to agriculture, such as soilmicroorganisms and insects. Not least, foodand nutrition analysis corresponds often to thespecies level, where, for example, as many as7,000 plant species are recognized globally asproviding food sources (6).

The genetic level—detected variously asbase pair sequences, molecular fragments inDNA, and allelic constituents—also showsthe management of both planned and asso-ciated components. A large majority of theplanned component consists of actively pro-duced landraces, farmer varieties, and localbreeds, whereas the associated component in-cludes the related wild crop relatives (WCRs)and livestock. Genetic diversity is extensiveand significantly more varied, both in extentand population structure, than the character-istics initially imputed to these taxa (33, 53–61). It also varies from well-defined popu-lations to metapopulations of relatively opensystems of gene flow. Important genetic ex-change via introgression and hybridizationoccurs between the domesticated taxa and theundomesticated yet closely related wild andweedy types (62, 63). Many potentially usefulagricultural adaptations to global change relyon these varied sources of genetic diversity onfarm and through the germplasm collections,broad-based lines, and stocks created and uti-lized in scientific breeding.

Spatial patterning and structures of geneflow reveal a higher level of genetic simi-larity among many populations of landraces,farmer varieties, and local breeds than was pre-viously understood (33, 53, 55, 57–60). Re-cent studies of the distribution of genetic varia-tion in existing agricultural landscapes—-scaledacross such units as fields, communities, andvillages, as detailed in the next section—relyon the upsurge and accessibility of molecu-lar techniques, especially simple-sequence re-peat and polymerase chain reaction methods.

WCR: wild croprelatives

Viewed broadly, the adaptive capacity, con-ferred through the biological diversity of cropsand livestock, is a function of gene flow andgenetic structuring within the combined taxo-nomic complexes of both domesticates and re-lated wild types co-occurring in complex agroe-cosystems (14, 64). Focus on gene flow andgenetic variation—within and among domesti-cated types and wild or weedy populations—isdesigned also to address transgenic introduc-tions and the risks of transgene diffusion (65–67). (The Cartagena Biosafety Protocol withits transgenic regulatory platform is discussedbelow as global social-environmental policy.)“Genetic erosion” (or the reduction of agro-biodiversity through losses, extirpation, andextinctions) affects genetic-level variation aswell as taxonomic levels of landraces, varieties,breeds, and domesticated species (34, 39, 68).

Agroecosystem, Landscape,and Higher-Order Levels

The agroecosystem is the composite struc-ture and functioning of biotic and abioticcomponents—similar to a habitat concept—and is typically scaled spatially to the field orfarm (see the next section below). Complexagroecosystems provide efficient nutrient cy-cling and water use in contrast to the exten-sive environmentally negative spatial externali-ties of monocultures and other low-complexityagriculture. Agroecosystem functions, by defi-nition, are centered on food and other crop andlivestock production. They also encompass nu-trient cycling; trophic interactions (such as in-sect or parasitoid herbivory, predation on cropsand livestock, and effects of predator enemies);and modification of local microclimates, soilnutrients, soil-water relations, and hydrologicprocesses (11, 13).

Biological diversity plays myriad importantroles, exerting both positive and negative effectson crop and livestock production, in the struc-ture and functioning of agroecosystems. For ex-ample, species-level diversity in crop rotationhas shown the potential for rotational “overyields” of greater than 100% of mean, resulting


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


GIS: geographicinformation system

from the interactions with soil nutrient man-agement of varied crop species in rotation (69).The diversity of functional groups or guilds ofspecies and possibly of other taxonomic levels inagroecosystems, rather than individual speciesper se, is the regulator of vital processes, involv-ing not only crops and livestock types but alsospecies-rich assemblages of insect, weed, soilbiota, and microorganisms (51, 52). Functionaldiversity of complex agroecosystems is gener-ally predicted to furnish services that enhanceyield stability, reduce risk of yield loss, and im-prove sustainability (9, 12, 13, 21). The agroe-cosystem level is useful also for identifying andintegrating predicted plant and animal physi-ological responses and other impacts of globalclimate change (22, 70).

The landscape and regional levels are alsokey units of analysis for biological diversity inagroecosystems (12). These levels correspondspatially to the patterning and ecogeographicdistributions of single diverse species and vari-eties (and genetic constituents) (45, 61, 71, 72).Landscape-level analysis is essential to under-standing agricultural intensification practicesand pathways amid global-scale change of suchfactors as climate, land use, and biogeochemi-cal cycles as well as policy and management (16,29, 31, 73–75). This level highlights the occur-rence of biological diversity in agriculture in thecontext of landscape mosaics and bioregions ofmixtures of agriculture and other land use. Ittends to be utilized as an analytic level in thesetreatments (rather than a scale per se) owingto pregiven spatial definitions. Landscape eco-logical concepts, such as patch-matrix interac-tions, can be applied to the interactions withinand among cultivated patches and nonagricul-tural landscape matrices (76, 77), such as WCR-containing woodland matrices interacting withcultivated patches of biodiversity in irrigatedagriculture (78). Landscape- and region-levelanalysis is particularly important because land-use change is often distinctive at this level (29).Region-level framing is also applied to biodi-versity in agriculture occurring across urban,suburban, and rural land use. Finally, it enablesanalysis of crop yield variation arising from in-

teractions of the spatial patterning of biologicaldiversity and climate fluctuation—particularlyrainfall shocks that resemble probable globalchange impacts (79).

The national, international, and global lev-els are the focus of institutions responsiblefor utilizing and conserving the aforemen-tioned forms of biological diversity in agricul-ture and, increasingly, evaluating informationat this level in relation to global change pro-cesses and projections. National-level analysisusing a geographic information system (GIS)approach, for example, has shown the high levelof variation among and within Mexican maizeraces for climate adaptation (80). Multicountryand international analysis using GIS has beenapplied to WCR potatoes in the Andean coun-tries, showing the distributions and areal pat-terning of taxa and ploidy types, illustratingthe sample bias of gene bank collections, andpredicting the geographic occurrence of traitsfor breeding, such as frost tolerance (81, 82).International- and global-level analyses also il-lustrate the worldwide concentration of biolog-ical diversity in tropical and subtropical regions,especially those of mountainous areas, foothills,and surrounding lowlands. These global “cen-ters of diversity,” described initially by Vavilov(83, see also 177) and located between 20◦ and45◦ latitude north and south, are a consequenceof environmental variation, prolonged agricul-tural history, diversity of human management(broadly defined), and genetic interaction withwild types (19, 33, 39, 83).

MANAGEMENT ANDSOCIAL-ENVIRONMENTALSCALING

Multiple geographic scales are central to ex-plaining the relations of the biological diver-sity of agriculture to the processes and patternsof global change. These scales arise from theinteractions of human activities and social or-ganization, on the one hand, and ecological andenvironmental processes, on the other hand.Different geographic scales tend to be dis-tinguished by distinct combinations of social

144 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


units and environmental characteristics. Differ-ing management activities also distinguish eachscale. Although biological diversity in agricul-ture appears to display a straightforward nestedhierarchy of geographic scales, there are alsonumerous crosscutting interactions.

Field and Farm

The scale of the field (and analogous areas ofanimal tending) is usually the primary site ofproduction and thus of planned managementof the biological diversity of varieties, breeds,and species of domesticated plants and animals.Actual scaling of the field is produced throughsocial-environmental interactions involvingfarm households, habitats, economic resources,and cultural knowledge. Areas and manage-ment vary widely. Multiple varieties, localbreeds, and useful species may be managedin conventional spaces of field cropping forrationales ranging from strictly utilitarianpurposes to social and cultural values invisibleto markets (37). The latter usages often supportagrobiodiversity-enhancing subsistence ratio-nales, providing a hedge against productionrisks—the so-called portfolio effect (73)—anda possible unrecognized latent or serependicbenefit (12). This planning includes both man-agement per se of the useful biota and certainproductive components, such as soil and pestmanagement, as well as a high level of culturaland social significance influencing the use ofthe field. The relative discreteness of fieldmanagement—most fields create a productionspace distinct from surrounding uncultivatedareas—is well suited to examining hypothesizedrelations of the planned and associated compo-nents of biological diversity in agroecosystems(13) as well as other spatial ecological modelsand studies of evolutionary dynamics underhuman selection (36, 45, 84). Managementchoice and other decision-making models arecentral to predicting the biological diversity ofvarieties (and landraces) at this scale (84, 85).Spatial modeling has used the twin field-levelparameters of production potential (e.g.,irrigation) and infrastructure availability (e.g.,

seed programs) to delimit a four-zone mosaichypothesized to predict within-field biodiver-sity at the level of varieties or landraces (84,86, 87). Also, for example, area and frequencyproperties correspond to management of thebiological diversity of useful plant speciesin home gardens as a distinct type of fieldspace (24, 47–49). Broader analogs of fields,such as swidden-fallow agroforests, also showintensive management of planned components,including trees for timber production (44).

The individual farm, often managedthrough a broadly defined household, is animportant scale determining the biologicaldiversity of agriculture (85, 88). Agrobio-diversity- and agroecosystem-related manage-ment decisions of the farm household scale upacross multiple fields and interconnected man-agement spaces (pasture, woodland, garden).Farm-level portfolios and economic activitiesincorporate such livelihood strategies as labormigration that shape household decisionsabout the on-farm extent and number of vari-eties, breeds, and species (89). Relations to thisdiversity can be estimated in economic modelsof the revealed and stated preferences of farmhouseholds (85). Variety availability/choiceand demand/desirability factors also operatein household decision making in determiningfarm-level biological diversity of agriculture.Additional multifactorial models have beendeveloped for biological diversity at both thecrop variety and species levels. They illustratethe importance of resource portfolios (accessto land, labor, seed) in addition to the roleof diverse management rationales at the scaleof the household and its collection of fields(market and nonmarket values, consumptiondemand, yield enhancement, risk reduction,and knowledge-based cultural and aestheticmodes of management) (37, 39–41, 46, 90).Farm management determines the propertiesof local variety richness and evenness, whichcan be aggregated to the community scale andserve as cornerstones of global estimates (91).Although on-farm models and frameworks areapplied primarily to the planned biologicaldiversity of crops and livestock, this scale of


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


management is similarly central to associatedbiotic and abiotic components, such as soils,organisms, insects, weeds, and wildlife, as wellas to the interaction effects of livestock andcrops (18, 54, 56, 92).

Community, Multicommunity,and Large-Area Scales

Community-scale practices, such as coordi-nated crop rotation, fallow, and nutrient flowsbetween fields and uncultivated vegetation ofcommunity lands, are central to many agroe-cosystem functions (12). Agroecosystem func-tioning at the community scale is incorpo-rated into larger multicommunity, landscape,or village-level areas (44). Procurement andexchange of seed offer a valuable illustrationof multicommunity and region-wide scaling ofbiological diversity in agriculture (36, 93–96).Whether genetic variation is differentiated atthis scale depends on the distance effects in seedexchange. For instance, region-scale and multi-community differentiation of genetic variationand varietal diversity are present in the farmervarieties of maize in Mexico and Guatemala andin the analogous units of potatoes in Peru (45,55, 61, 72). Alternatively, these spatial-distanceeffects may be minor and thus result in geo-graphically widespread genetic similarity (57).Nonlocal seed procurement and exchange ap-pear to be relatively common as key spatial flowsstructuring the biological diversity of variouscrops and livestock and, potentially, offering animportant source of adaptive traits in responseto environmental change.

Scaling is evident in national, international,and global management, primarily through theaggregation of effects of lower scales, discussedabove. Still the increasing number and scopeof national institutions and other organizationshave supported programs incorporating biolog-ical diversity in agriculture, even though theprograms were aimed primarily at such goalsas food security and local production, organicfarming, and soil conservation (85). The growthand consolidation of multifunctional policiesin European agriculture, for example, offer the

examples of national and international manage-ment that can reasonably be expected to haveregion-wide impacts. Other effects of manage-ment scale may be less uniform, notwithstand-ing national-level sanctioning. For example,the national projects conserving varietal andspecies diversity in the agroecosystems of An-dean crops—widespread in Peru, Bolivia, andEcuador—tend show strong subnational or re-gional spatial concentrations.

GLOBAL CHANGE FACTORSAND PROCESSES

Biological diversity of agriculture is tiedclosely, albeit in varied ways, to global en-vironmental changes. Differing trajectoriesof global land-use change combine with themodification of climate and water factors tocreate extensive interactions at the level ofagroecosystems. Soils and nutrients are alsoimportant factors in the global change interac-tions of agroecosystems. Agroecosystem-levelanalysis provides insights into approaches tohuman-social mitigation and adaptive capacityin response to global environmental changes,such as agroforestry and high-agrobiodiversityfarming. Such changes are concentrated inglobal agrobiodiversity hot spots, describedbelow, that are vitally important to world foodsupply at present and in the future.

Land Use, Climate, and Water

Biological diversity of agriculture is impactedsignificantly through multidimensional globalchanges of land use and land cover. Prevail-ing transitions toward more intensive produc-tion in agricultural areas worldwide are of-ten based on new or expanded adoption ofmodern varieties and oftentimes monoculture(19, 30, 39). This land-use change has signifi-cantly reduced crop and livestock diversity. Itleads also to other agroecosystem simplifica-tions, such as reduced soil and abovegroundbiomass and organic matter; lower levels of in-sect, soil, and faunal biodiversity; soil erosion;and restricted nutrient cycling, as well as to

146 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


increased release of carbon dioxide (CO2),nitrogen, and phosphorous (30, 31, 97, 98).Second is the consequence of converting previ-ously uncultivated ecosystems, principally trop-ical and subtropical forests and grasslands (1,7). This typically results in low-biodiversityagriculture—from extensive livestock raising tothe immense agrochemical-dependent soybeanboom in South America—and has become achief topic of approaches such as global land-use cover change (LUCC) and land-cover sci-ence (LCS) (29, 99). At the same time, projectedimpacts of global climate change underscorea growing importance of other environments,such as marginal habitats in arid and semiaridregions (3), where noticeable impacts are pre-dicted to affect biological diversity in existingagroecosystems. Third, accelerated disintensi-fication, including reduction of swidden and in-creased forest cover, shows signs of reducing bi-ological diversity in agriculture (50) and raisesthe important issues of agroecosystem qualityand landscape functioning in secondary foresttransitions (77). Land-use expansion and inten-sification, as well as disintensification, are pro-pelled through the milieu of global socioeco-nomic, technological, demographic, and policyfactors, particularly by global market integra-tion (as discussed in the section below on glob-alization and development).

Climate is a predominant element amongglobal change factors projected to impact sig-nificantly on biological diversity in agriculture.Although few studies have focused specifi-cally on global climate change in relation tobiological diversity in small-scale agriculturalmanagement, general impact processes are in-creasingly well-known (3, 83, 100). Intensifieddrought in tropical and subtropical areas, grow-ing season extension, and prevalence of extremeclimate events (floods, windstorms) are theprincipal projected and recorded abiotic effectsof global climate change. Adaptation to theseeffects is forecast to require the accelerated useof genetic resources in breeding new modernvarieties of plant and animal domesticates (4,101, 102). Especially important then is theimpact on farmer varieties and local breeds in

LUCC: land-usecover change

LCS: land-coverscience

globally concentrated areas of biological diver-sity in agriculture, particularly in tropical andsubtropical environments, as well as in certaintemperate regions (45). Many of these globalconcentrations are likely to be exposed to signif-icant environmental changes. Climatic destabi-lization and shifts in temperature, precipitation,soil water regimes, pests, weeds, or diseasescould undermine the feasibility and productionof agroecosystems and constituent usefulbiota containing globally important geneticresources (14, 83, 101). Spatial overlap of theworld’s agrobiodiversity concentrations withpronounced threats owing to climate changes—as well as land-use pressures—indicates theimportance of building new understandings ofthe dynamics and delineation of geographicareas of global agrobiodiversity hot spots.

Changing characteristics of agroecologi-cal zones, each corresponding to mixtures ofplanned and associated elements, are useful ap-proximations of the spatial dimension of cli-matic shifts (103). For example, locally con-centrated biological diversity of various crops,livestock, and agroecosystems is expanding up-slope in the tropical Andes. This climatechange, together with the elevation shift andintersecting topographic effects, is resulting inincreased demands for irrigation and produc-tion of the biological diversity of Andean maizelandraces. Concurrently, shrinking farm habi-tat availability is besetting agroecosystems ofAndean potato species, landraces, and high lev-els of associated biological diversity. Althoughscientific breeding of a next generation of mod-ern varieties is forecast to lessen the risk ofglobal yield losses in the major cereal crops(101, 104), prospects and impacts are signifi-cantly less known and potentially more nega-tive for globally important root and tuber crops,such as potato, cassava, yam, and sweet potato.WCR and wild livestock relatives also are facedwith global spatial-environmental shifts of suit-able habitats that could undermine these impor-tant undomesticated populations (105).

Adaptability and limits likely to impinge onzonal shifts of farmer varieties and local breedscan be surmised through the relation of current


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


elevation-related climatic variation to existingdistribution, genetic variation, and adaptation(45, 55, 72). These studies also include cross-elevation common garden experiments assess-ing yield, seed production, and other ecologicalfitness indicators (61, 106). Substantial adap-tive capacity, albeit unevenly distributed amongtaxa, is demonstrated in the maize crop inMexico and Central America as well asAndean potatoes in Peru. Global climatechange also is leading to new dynamics and spa-tial patterns of pest, disease, and insect prob-lems in agroecosystems, such as the increasedlikelihood of fungal outbreaks (104, 107, 108).Complex agroecosystems based on higher levelsof biological diversity are predicted to providecrop protection and stabilize production (11,13). Enhanced levels of organic matter in theseagroecosystem types, such as organic agricul-ture and agroforestry, generally emit less CO2

and methane and thus mitigate global climatechange (31, 109). Similarly, the techniques usedin these agroecosystems, such as crop rotationand cover crops, reduce emission of nitrous ox-ide (N2O) (98).

Changes in water resources are a projectedconsequence of both global climate shifts (in-creased evapotranspiration rates, regionally re-duced rainfall, and lessened water supply fromshrinking mountain glaciers) and the effects ofsocial-environmental globalization (increasedwater for agricultural, urban, and industrial de-mands worldwide) (3, 4, 83, 86, 110). Such com-bined social-environmental changes, which arespatially uneven among geographic regions, re-sult in water shortages for agriculture in manyareas. Agricultural impacts include direct loss ofcrop and livestock production stemming fromwater deficits. Biological diversity of farmer va-rieties, local breeds, and other agroecosystemcomponents are subject to declines of wateravailability below needed limits (111). At thesame time, many of these resources are vitalin potential adjustments to increased water-saving and intensified management, such as wa-ter harvesting and diversified irrigation (112,113). The biological diversity of agricultureis basic to cultivation of crops with greater

water-use efficiency (31). Emphasis on the latteris likely more important to agricultural adapta-tion than breeding responses to increased tem-perature or CO2 concentration per se (104).Potential adaptive capacity stems from avariation of traits, such as maturation pe-riod in existing species and variety diversity(78, 104, 114). Such adaptive capacity de-pends also on innovative water-managementtechniques, locally appropriate technologies,and institutions and infrastructure that buildupon existing agroecological variation anduse of biological diversity in agriculture.Water-related risks in global change also in-clude increased flooding and rainfall inten-sity. Responses include adaptive land use basedon coordinating high-agrodiversity croppingat the community scale (92) and, in somecases, aggregated to landscape and regionallevels (79).

Agroecosystems, Soils, and Nutrients

Scenarios of global climate change project sig-nificant alterations of the geographic distribu-tion, spatial patterning, extent, and agroecosys-tem impact of field weeds, insect pests, andplant pathogens (3, 4, 5, 107, 108). In cer-tain agroecosystems, such modifications willworsen the yield-reducing effects of increasedtemperature and lengthened growing seasons,especially where these trends combine with in-creased precipitation (14, 104). Beneficial com-ponents of biodiversity in agriculture also maybecome impacted as a result of global climatechange. For example, mycorrhizal fungi, manyof which deliver important nutrient cycling toagroecosystems, are likely to be impacted nega-tively. Adaptive responses to yield-reducing dy-namics of altered agroecosystems are certain torely on scientific breeding and use of genetic re-sources in the biological diversity of farmer va-rieties and local livestock types (4, 5). Adaptiveresponses also include the design and manage-ment of complex agroecosystems with amplebiological diversity, such as guild-level varia-tion of beneficial insect populations, to mitigateyield reduction (11).

148 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Strong multidirectional interactions of soilenvironments are vitally important to biolog-ical diversity in agriculture in the contexts ofglobal land use and climate changes. A majorityof global land-use changes, associated with agri-cultural intensification, lead to degradation inthe forms of soil erosion, compaction, reducedorganic matter, and biotic simplification. Bycontrast, these sorts of soil changes are typicallylessened in agriculture resembling natural sys-tems, including agroecosystems with greater bi-ological diversity (103). Global climate changeis projected to decrease soil water availability,which will exert agroecosystem impacts on suchcomponents as soil hydrology and organic mat-ter. Both impacts will vary noticeably amongworld regions. For example, climate change inthe subtropics is likely to dry soils and accel-erate organic matter decomposition, with im-pacts that could lead to soil crusting, particu-larly of sandy soils. Impacts are highly probableon the biological diversity of soil organisms—including the vast variety of soil micro- andmesofauna, algae, lichens, protozoa, fungi, bac-teria, viruses, and macrofauna, as well as ver-tebrates such as lizards and rodents—many ofwhich are sensitive indicators of climate andland-use changes. Climate change also is likelyto worsen the rates and increase the spatial ex-tent of soil erosion in certain regions as a re-sult of extreme rainfall, soil drying, and reducedvegetative cover (115). Soil erosion underminesthe productive capacity and functioning of bi-ological diversity in agriculture, ranging fromfarmer crop varieties to vegetation, soil, and in-sect biota (116). Soil resilience is anticipatedto increase elsewhere, mainly in midlatituderegions (117).

Agroforestry and soil conservation ap-proaches relying on biodiversity can aid inadapting agriculture to more erosion-proneconditions of climate and vegetation. Con-versely, biological diversity in agriculture isan important source of CO2 sequestration andthus influences the mitigation of global climatechange. Soils with higher biological diversity(including the food web structures and commu-nity function of soil biota) store greater biomass

and hence organic carbon, which tend towardhigher levels of water retention, nutrient cy-cling, and carbon sequestration than underconventionally managed agroecosystems (118).No-till management, which increases carbonsequestration (116), results in increased soilorganic matter and agroecosystems generallymore favorable to biological diversity. Higherlevels of soil organic matter are also more fa-vorable, in general, to yield increases of farmervarieties and landraces, and thus create impor-tant conditions for production at this level.

The global change impacts of significantlyaltered biogeochemical cycles (28, 31, 97) alsobear bidirectional relations to biological di-versity in agriculture. Ecological consequencesof massive global leaching and atmosphericrelease of nitrogen are linked to modernagriculture, fossil fuel combustion, and otherhuman activities. Excess nitrogen is presumedto impact negatively on the complexity ofbiological diversity in agroecosystems similarto disruptive influences on other ecosystems.Mitigating and adapting to anthropogenicnitrogen loading highlight the important roleof biological diversity in agriculture neededfor cultivation of crops with high nutrient-useefficiencies (31, 98, 119). More fundamentally,the increasingly well-studied functioning ofbiological diversity in land use, evidenced inexpanding agroforestry (2, 24), can result in thereduced leaching of nitrates and phosphorous(13, p. 7; 98, p. 113). Efficient use and cycling ofnitrogen and phosphorous in agroecosystemsis fundamental to addressing these globalenvironmental problems (31, p. 673).

SOCIAL-ENVIRONMENTALINTERACTIONS

Various social-environmental interactions gov-ern the influence of global change factors thatwere discussed in the pair of preceding sec-tions. A host of specific interactions are in-fluential and must be seen as creating com-plex couplings in the current use and futurefate of the biological diversity of agriculturewhen viewed in the context of global change.


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


These particular social-environmental interac-tions include processes of economic develop-ment, market integration, social and culturalchange, land-use change pathways (intensifica-tion and disintensification), technology change,and the role of global policies and institu-tions. Several paramount change-producing in-teractions involving biological diversity in agri-culture are conditioned through globalizationprocesses, with several influential changes alsotaking shape via political and economic policiesassociated with neoliberalism.

Adaptive Capacity

Adaptation and mitigation are responses ona continuum of social-environmental adjust-ments to global change (102, 112). Adaptationrefers to adjustments to both environmentaland broadly social changes; adaptability ishaving secure access to this capacity (15).Mitigation refers to adjustment involving thepurposeful lessening of detrimental change (4).Although both adaptation and mitigation mayrely on biological diversity in agriculture, thelatter’s role is highly varied in its particulars.Its principal contributions to global changeresponses are usually conceived as scientificproduction of crop and livestock types anddeveloping land-use systems suited to changingenvironments (101, 102). Still the mechanismsfor these contributions are wide ranging, andthe potential for contributing to adaptationand mitigation must also be seen more broadlyin the context of existing social-environmentalcapabilities. Capacities of individual land usersas well as social groups and governance insti-tutions, such as communities, resource-useraggregations, farmer federations, nationalgovernments, and nongovernmental organiza-tions (NGOs), exert strong influences on theadaptive use, whether existing or potential, ofbiological diversity in agriculture and land use.Adaptive capacity in this context is conditionedthrough such social-environmental processesas vulnerability, resilience, stressors, sensitivity,exposure, buffering, coping, thresholds, andjustice (114, 120–125).

While modern varieties, technologies, andplanting techniques adjust to altered plantingdates and phenological shifts stemming fromglobal climate change in midlatitude locationsof advanced industrial agriculture (5, 102,109), there are less documented yet extensiveresponses among poorer farmers in many otheragricultural regions worldwide. The lattergroups of land users and their communities areactively altering their use of biological diversityin such activities as crop and livestock pro-duction, processing, storage, and consumptionactivities. Many inhabitants of tropical and sub-tropical regions of developing countries tend tobe the most exposed and vulnerable to the com-bined social-environmental dynamics of globalchange (4, 5, 100, 102, 121, 123, 124, 126, 127).They include large numbers of indigenous peo-ple, peasant smallholders, and ethnic and racialminorities. Their adaptive capacities dependon resource endowments—the portfolio effectsmentioned above—and resilience properties,including their social relations and practices,cultural knowledge, skills, and institutions inthe management and biological diversity oftheir agroecosystems. Such responses mightinclude new types and mixtures of farmervarieties, local breeds, and useful species withinproduction repertoires, including intercrop-ping (multispecies) and crop rotation (41, 128,129). Agroecological functions, such as effectsof soil biota, potentially enable their farmhabitats to contain higher levels of biologicaldiversity to better withstand the effects ofreduced rainfall and increased drought stress(116). Biological diversity of agriculture andvulnerability of land users are anticipated toplay influential roles in the expansion of smalland medium-scale irrigation and water re-source management, such as water harvestingand other innovations being developed inresponse to global climate change (78, 112).

Globalization and Development

Social-environmental adaptation and mitiga-tion occur amid global integration (global-ization) of broadly social factors—including

150 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


economic, political, cultural, technological, andpolicy changes—interacting with biological di-versity in agriculture and the effects of climateand land use in global change. The directional-ity of impacts is primarily negative, though notentirely, in interactions of globalization withthe biological diversity of agriculture (130).Global integration of agricultural markets forstaple foods, for example, has tended to un-dermine the widespread cultivation of farmervarieties of such foodstuffs as wheat, rice, andmaize in more marginal growing environments.This market integration has been guided chieflythrough neoliberal policy approaches, such asNorth American Free Trade Agreement agri-cultural and environmental arrangements (130,131). It has disadvantaged the production ofstaple foods in numerous regions of complexagroecosystems, especially those in marginalrural environments. More widespread is the de-terioration of biological diversity in agroecosys-tems as a direct result of expanded emphases onmodernized export agriculture (132).

Still globalization is known to induce avariety of spatially and socially differentiatedimpacts, including unintended consequences,resulting in significant capacity for continuedbiological diversity of agriculture at the scalesof farm households, communities, and regions(19, 41, 85). Market integration also can favorthe popularity of biologically diverse “cre-olized” crop varieties—derived from mixturesof modern varieties and local landraces—andpotentially analogous livestock breeds (133).Still the biodiversity contained in creole maizelandraces, for example, appears less than tradi-tional counterparts in a recent study in southernMexico (34). Globalization may result in thesomewhat ironic twist of stimulating prefer-ences for locally traditional dietary items, rein-forcing biological diversity in agriculture (134),even while this parameter is impacted predom-inantly negatively in the general interactionwith food consumption trends at a global scale(6). Primarily positive impacts, by contrast, arepresumed to result from globalization in theform of expanding movements supporting localfoods, organic agriculture, fair trade, and mul-

tifunctional agriculture conducive to biologicaldiversity in agriculture (135, 136). Overall, theeffects of aforementioned global changes arestill relatively unknown in relation to biologicaldiversity in agriculture, especially in the multi-tudinous processes associated with agriculturaldevelopment and policy (16, 49, 89).

Agricultural Intensification,Disintensification, and Food Security

Agricultural intensification is a predominantform of global land-use change, both duringthe past century and currently (19, 30, 31,137), encompassing combined social, envi-ronmental, and economic dynamics (definedabove). Intensification via land use and agroe-cosystem transformations is propelled throughmarket integration and policy effects on farmproduction (including neoliberal policies, seeReference 131), food security concerns, andresponse to global environmental changes. Itis typically tied to the prospects of the majorcereal crops (129). Intensified agriculture, withincreased levels of farm management, is gener-ally more capable of responses to global climatechange than smallholder production (107). Theinfluence of fixed or sunk investments on farm-level decision making is primarily a positivecontribution toward social-environmental re-silience in the context of global change. It can,however, hinder adaptive capacity if it slowsadoption of resilience-enhancing practicesunder particular circumstances. Focus on foodsupply and concerns over food security canpotentially help frame agricultural intensifica-tion among land users and their societies andagroecosystems (including biological diversityin agriculture) as ethical and justice issues.This new framing would potentially resemblevulnerability assessments of resource usersunder global climate change (100, 120, 124).Indeed food sustainability and security issueshave become cornerstones of major new policyinitiatives, such as the Global Nutrition Strat-egy in sub-Saharan Africa, that place emphasison biological diversity in the production andconsumption of local agricultural goods (138).


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Much is at stake for biological diversity infuture trajectories of agricultural intensifica-tion. On the one hand, use of multiple use-ful species in space (intercropping) and time(crop rotation and cover crops), as well as agro-forestry, are potentially promising elementsof enhancing nutrient efficiency and carbonstorage in agricultural intensification (31, 98).Existing trajectories of agricultural intensifica-tion suggest complex, nonlinear relations to bi-ological diversity (13, 17, 41, 78, 139, 140). Atthe level of farmer varieties and local breeds, forexample, certain intensification pathways haveproduced shifts to single types in field monocul-tures, whereas the significant ecological rich-ness and widespread biogeographic occurrenceof high-agrobiodiversity types are characteris-tic of the community, landscape, and regionalscales. Agricultural intensification also providesa means of potentially expanded nonagricul-tural protected areas and programs, such as re-duced deforestation and reforestation programs[i.e., reduction of emissions from deforestationand forest degradation (REDD)] (7, 141, 142).This pathway, which posits trade-offs, would fa-vor outcomes of nonfarm biodiversity conserva-tion and ecosystem services (2) and presumablysupply biofuels and other nonfood products. Onthe other hand, intensification changes mustbe seen in general and in numerous case stud-ies as significantly increasing the use of agro-chemicals and water resources, as well as of newcrops, cultivars, and livestock breeds, with a cor-responding reduction of biological diversity inagriculture (30, p. 504; 137).

Other distinct pathways of agriculturalchange also exert regionally important im-pacts. Such locale-specific changes includethe local or regional formation of agriculturalcooperatives or, conversely, a general disinten-sification trend, propelled through regional,national, and global integration of marketfactors (24, 136, 143). Variants of the lattertrend include deagrarianization (completeabandonment of agriculture) and “repeas-antization” (increased subsistence growingwith market integration). Repeasantizationin particular has become somewhat common

in marginal rural environments, includingthose comprising probable global hot spots ofbiological diversity in agriculture. These sortsof changes demonstrate complex relations. Forexample, agricultural disintensification canundermine or enable biological diversity inagriculture by either eroding the productivecapacity needed for farmer variety and breedproduction or, alternatively, by reducing land-use pressure and improving agroecosystemquality. Furthermore, trends of locale-specificdisintensification tend to be closely linkedthrough global integration of market factors(e.g., labor, land, products, resources) toregions of agricultural intensification.

Technology Change

Innovation, diffusion, and adoption of newtechnologies, along with corresponding knowl-edge systems, are central to the impacts andinfluence of biological diversity in agriculture.Seed varieties and livestock breeds are cor-nerstones of modern technological change.Influential too are myriad production, pro-cessing, transportation, communication, andrelated market and consumption technologies,impacting directly on food and land use and, byextension, on biological diversity in these agro-ecosystems. Technological change in moderncrops and livestock types, scientifically pro-duced and promoted, was a vanguard of theglobal Green Revolution, along with input andmarketing technologies that impacted biolo-gical diversity in agriculture at levels rangingfrom farmer varieties to agroecosystems (19).Present-day biotechnology plays a major rolein projections of adaptation to and mitigationof global change (103, 129, 144). Still thistechnological adoption may worsen the risk offood shortages and contribute to food crisesamong the world’s poorer people, particularlyin rural areas (144), whereas valuation ofthe biological diversity in their agricultureraises the hypothetical possibility of benefitsunder increased biotechnology adoption (101).Possible transgene diffusion has fueled analysisof gene flow (145), including new findings on

152 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


its unexpected commonness among certainwild and cultivated crop populations (65). Farmmanagement practices often determine theoutcomes of technological change, includingthe potential spread of introgressed crop typesthat could contain transgenes (66). In the caseof transgenic risks to the biological diversity ofmaize in Mexico, the potential impact of trans-genic types is influenced through farmer-basedseed selection and management (146, 147).Other factors include probable low initial ratesof transgene occurrence, possible lack of phe-notypic expression, and spatial-environmentalsampling effects (148). Changing technologiesand interactions with biological diversity inagriculture are subject to the powerful roles ofpolicy and institutions, particularly those withincreased influence at the global scale.

Global Policy and Institutions

Globalization is also represented in legal in-struments, policy guidelines, and institutionaldevelopments. This global change is primarilypositive, albeit muted in overall impact onboth the biological diversity in agricultureand the potential capacities for its use inadaptation and mitigation of global change.The 1992 Convention on Biological Diversity(CBD), especially Agenda 21, along with the1996 Conference of Parties, has provided animportant international legal framework thatmay be applied to on-farm conservation (149).This application is nominal, however, for avariety of reasons involving the agreement’sscientific and policy frameworks (42, 150).With implementation on June 29, 2004, the In-ternational Treaty on Plant Genetic Resourcesfor Food and Agriculture, especially Article 6,was designed to ensure sustainable use of theseresources (15). Although global in scope, thetreaty’s effectiveness is partial to date (151).The 2002 Cartagena Biosafety Protocol was de-signed to ensure assessment of transgenic risksand protection of biological diversity (145).Still the socioeconomic issues of intellectualproperty rights, and particularly the policiesand patents on seeds related to modern and

CBD: Convention onBiological Diversity

transgenic types, probably exert more impact(67). Reactive national proprietary rights-basedrestriction of access to farmer varieties and lo-cal breeds also is argued to hinder the fuller useof biological diversity in agriculture (151–153).

Global organizations fashion social-environmental change promoting the bio-logical diversity of agriculture. The globalConsultative Group for International Agricul-tural Research (CGIAR) centers, once nucleiof the Green Revolution, have been downsizedalong with privatization of agricultural researchworldwide. To varying degrees, these centers,such as Centro Internacional para el Mejoramientode Maız y Trigo (CIMMYT) and Centro Inter-nacional para la Agricultura Tropical (CIAT),now specialize in research and implementationof the collected and on-farm conservationof diverse farmer varieties and breeds (152,153) (see the following section). BioversityInternational [formerly the InternationalPlant Genetics Resource Institute (IPGRI)and before that the International Board ofPlant Genetic Resources (IBPGR)] and theInternational Food Policy Research Institute(IFPRI), which belongs to the CGIAR, areglobally prominent in promoting biologicaldiversity in agriculture along with food securityissues (138), as are a large number of interna-tional agencies, NGOs, and foundations. Thegrowing success of these global organizationsincludes a large number of local and regionalNGOs and projects worldwide, involving manycommunity groups and social movements ofpoorer farmers who are more socially and en-vironmentally vulnerable and whose incomesand food production and security can benefitfrom conserving and enhancing biologicaldiversity in their agroecosystems (e.g., 6, 10,19, 24, 40, 78, 83, 93, 96, 121, 127).

CONSERVATION ASSESSMENTAND MONITORING

Conservation and sustainability are central tothe present and future roles of the biologicaldiversity of agriculture in the context of globalchange. Significant advances have occurred in


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


both ex situ and in situ approaches as appliedworldwide to conservation and sustainable use.Still, substantial reduction, local loss (extirpa-tion), and extinction have occurred. There re-mains a long way to go in developing a suitableset of monitoring approaches and in further im-proving and better integrating biological diver-sity of agriculture into conservation and sus-tainability designs. Developing these capacitiesis made especially urgent and vitally necessaryby global change that is both underway andprojected.

Conservation and Sustainability

Conservation of biological diversity in agricul-ture, both the planned and associated compo-nents, is a major goal in developing effective andsustainable responses to global change. Farmercrop varieties and livestock breeds are seento hold value as genetic resources and breed-ing stocks for both on-farm and off-farm uses:(a) on-farm for environmental adaptation andadaptive capacity, food production, and variouscultural purposes (17, 19, 39–41, 71, 73, 74,78, 151, 154); (b) on-farm ecosystem services(2, 16, 42); and (c) off-farm breeding and sci-entific “improvement” programs (14, 54, 140,144, 152). These varieties and breeds are tar-geted in expanding global conservation effortsthat have evolved from storage repositories (exsitu conservation) and allied breeding facilitiesto a dual strategy combining the potential forlocal breeding and accessible storage with con-tinued on-farm production (in situ conserva-tion) (71, 149, 151–153). Significant evidenceof the latter includes extensive de facto contin-uation of the use of farmer varieties and breedsin complex agroecosystems worldwide (19, 39,41, 54, 83, 86, 94, 155).

Principal approaches aimed toward the goalof in situ conservation are actively engagedwith issues of global change that includeland use, climate, and economic systems andwith attempts to leverage the use of globalagreements and policies of global organizations(such as the 1992 CBD). This conservation isdynamic in enabling continued evolution of

farmer varieties and breeds as an integral partof coupled human-environmental systems inthe context of environmental stressors. Bothparticipatory plant breeding and seed systems,for example, feature the role of farmers andfarmer groups, such as community-based orga-nizations, in the design, evaluation, selection,and dissemination of existing or new farmervarieties and local breeds (32, 40, 152, 156–159). These approaches are being promotedglobally as effective means of improving foodsecurity. One main rationale for capitalizingon local agrobiodiversity is to respond to en-vironmental variation that is both spatial (suchas heterogeneity of farmland) and temporal(climate fluctuations and change). The per-spective of genetic resources is integral to theseapproaches, with insights from conservationand landscape genetics on multiscale and in situversus ex situ partitioning of biological diver-sity (53, 160). Related interest is centered onfarmer varieties and breeds as agrobiodiversity-conserving elements of local responses tomarket conditions and policies within thecontext of global social-environmental change(85). Conserving the planned component insitu and the associated agroecosystem func-tions depends on farmers taking advantage ofadequate admixtures of income generation, riskreduction, adequate consumption qualities,and environmental adaptation and resilience.

The associated component of biologicaldiversity in agroecosystems is equally vital tosuccessful conservation and use in responseto global change. Various management ap-proaches figure prominently in this component.Protected area conservation has undergoneextensive global expansion leading to unprece-dented interactions with and importance toagricultural landscapes, and vice versa (76, 154).Although still aimed principally at protectionof wild biodiversity, it also places increasedemphasis on ecosystem management and adap-tation to climate change in these strategies. Pro-tected area conservation similarly is of increasedimportance to the conservation and sustainableuse of numerous WCR and the wild relatives ofdomesticated animals (154, 161). Low-intensity

154 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


land use and agriculture can be integral to con-servation management, as in the case of peren-nial maize (Zea diploperennis) in the Sierra deManantlan Biosphere Reserve, Mexico. Watermanagement, which is subject to sizeable ex-pansion in response to climate change, exhibitsa growing reliance on small- and mesoscaleirrigation (112, 116) and thus new opportu-nities for incorporating biological diversityin agriculture (78). Management support ofagroecosystem services, potentially throughpayment-for-environmental-service projects,is an important opportunity for contributingto conservation of the associated componentsof biological diversity of agriculture (2, 16, 42).

Reduction, Loss, and Extinction

Reduced ecological well-being of plannedcomponents, principally farmer varieties andlocal breeds of domesticated animals, is aprincipal indicator of the local or regionalloss (extirpation) and extinction of biologicaldiversity in agriculture through the processof genetic erosion. Overall loss of geneticdiversity may be as high as 75% during thepast century, and continued decline is posinga significant risk of global proportions (162).Still, rates of genetic erosion appear to haveslowed, at least in certain crop complexes andregions. For example, the estimated annualrates of genetic erosion of wheat landraces inItaly fell from 13.2% beginning in the 1920sto 0.48% to 4% in the 1990s (68). Althoughthe spatial coverage of modern varieties isextensive, the pace of adoption appears to belessening and is checked by high transactioncosts among other factors (163, 164). Partialpersistence of farmer varieties and landraces(86), and presumably local breeds as well, ben-efits also from values quantifiable as “shadowprices,” undervalued in current markets (37).The varietal replacement model of geneticerosion, which was once adhered to nearlyuniversally among scientific researchers andpolicy experts, is now seen as comprising onlyone of the pathways of genetic erosion (163).Urbanization and industrialization, as well as

changes under intensification combined withdisintensification effects, often serve as themost potent forces displacing and underminingproduction at present (86). Larger spans oftime and geography underscore the severity ofhistorical reduction, local- and region-scale ex-tirpation, and even the biological extinction oftaxa (162, 165). Local and regional losses mayincur significant social and cultural disempow-erment among certain groups of producers,such as indigenous and peasant women, andthis risk has continued to grow (90). At thesame time, public perceptions among bothexperts and citizens at national levels arerelatively uncertain with respect to the overallnature of the risk of genetic erosion and thusweaken the potential of policies building uponthe precautionary principle (166).

Reduced levels are also evident in associ-ated components of agroecosystem biologicaldiversity and function. This reduction at theagroecosystem level is a consequence of tech-nological change; market integration (products,labor, inputs); the use of hybrid germplasm,modern scientific varieties, and industrialbreeds; and agricultural modernization policies,institutions, and projects (13). Soils, for exam-ple, show the drop-off of functional biodiver-sity as a result of organic matter loss and shiftsto agrochemical inputs. In general, the focusof conservation policy and practical studies hasshifted from threats—common in well-knownstudies of the 1970s and 1980s—to a subse-quent and ongoing emphasis on persistence, re-silience, and flexibility applied in particular tofarmer varieties, landraces, and breeds.

Monitoring

Monitoring approaches and methods have beendeveloped for assessment of the conservationstatus and capacity for response to globalchanges in both planned and associated compo-nents of the biological diversity of agriculture.Procedures have been designed to compare di-achronic estimates and measure the loss rate ofthe number of farmer varieties and local breedsin a wide range of places that are located in


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


and near global concentrations of agriculturalbiological diversity (39, 41, 68, 86, 94, 95, 155).Innovative techniques are being used to esti-mate past genetic erosion based on comparisonsacross present-day taxonomic groups withinhigh-agrobiodiversity crop and livestock com-plexes, especially varieties and stock that are re-ferred to as traditional and creolized varieties(34). Scientific research, together with conser-vation and development analysis, has also gen-erated benchmark information on associated bi-ological diversity in agroecosystems worldwide(61, 72, 85, 91). Innovation of monitoring activ-ities is responding to pressures to demonstratecompliance with policy agreements, such as theCBD (162).

Design of local evaluations—which couldbecome incorporated into monitoring—is be-ing scaled up to larger areas as a focus of recentglobal comparisons (91). Scaling-up is also apriority in the monitoring of adaptive capacitiesresponding to global change. A proposed globalnetwork of in situ conservation sites incorpo-rates monitoring information on biological di-versity in agriculture (principally at the levelof farmer varieties and local breeds) allied tosupport of adaptive responses to global change(151). Interest has grown also in monitoringapproaches designed for the associated compo-nent of biological diversity in agroecosystems.Proposed methods include the development ofrapid biodiversity assessment for agroecosys-tems and analysis of landscape structure andfunctioning (73, 74). The latter criteria suggestuse of analytic frameworks combining GIS andimagery techniques along with possible integra-tion of the LCS and LUCC approaches (1, 78).These techniques and methodologies are cur-rently foundations of multiscale studies, sug-gesting the promise of new monitoring effortsaimed at biological diversity in agroecosystems(78, 81, 82, 162).

CONCLUSION

Biological diversity of agriculture, which iscomposed of multiple analytic levels and man-agement scales, is subject to increased interac-

tions with global change. The latter encom-passes global land use and climate changes,as well as broad-based social-environmentalchanges (globalization of agricultural develop-ment, market integration, and technologicalchange, as well as regulation through globaltreaties, policies, and institutional networks).While the biological diversity of agricultureis impacted through these changes, it also ex-erts influences. To understand these multidi-rectional interactions and changes, it is neces-sary to consider the linkages across factors andprocesses associated with four conceptual ar-eas. These nodes, as they are described above,are biological diversity in agriculture; globalchange; management and scale; and social-environmental adaptation, vulnerability, andresilience.

Both promise and peril are characteristic ofthe coupled interactions of the biological diver-sity of agriculture and global change. Relationsto global change factors—from land use andclimate to social-environmental globalization,technology, and policy—are complex, nonlin-ear, recursive, and multidirectional, and alsofrequently bear unintended consequences. Sig-nificant numbers of current interactions canbe identified as either positive or negative forthe fate of biological diversity in agriculture.Global land use and climate change propel sci-entific breeding to place a premium on the bi-ological diversity of farmer seed, animal stock,and agroecosystems to produce modern vari-eties, breeds, and intensive production capabili-ties adapted to changing environments. A seriesof relatively new and still incompletely imple-mented global treaties and policy agreementsnow support biological diversity in agriculture.Global integration of certain economic marketsfor products, investments, and labor, combinedwith cultural and social trends, has driven theexpansion of organic agriculture and local foodmovements, offering advantages for biologicaldiversity in agriculture (albeit with conditionsimposing important limitations). Furthermore,an impressive number and scope of global or-ganizations have become active in supportingand seeking to conserve biological diversity in

156 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


agriculture through an unprecedented growthin global assessments, monitoring, and coordi-nation. Indeed, these institutions with explic-itly global missions have generated interest, in-spiration, and awareness in addition to policyguidelines, scientific analysis, and the growingcontribution of publications (16, 42, 43, 85).

The reality of formidable threat also con-fronts the biological diversity of agriculture,along with the users of these resources, who arefaced with global changes. Various interactionsare resulting in the reduction of agroecosystemcomplexity, loss of farmer varieties and localbreeds, and the likelihood of worsening globalchange impacts. Global land use and climatechange drivers, in addition to market integra-tion and demographic factors, are increasingagricultural intensification. Predominantpathways of intensification lead to loss of bi-ological diversity in agriculture. For instance,widespread intensified agriculture, basedprimarily on a new generation of cereal cropsalong with high-input farming systems, is likelyto precipitate major losses to existing agro-

ecosystems. At the level of farmer varieties andlocal breeds, such losses are likely not to occurprincipally through the process of replacement,once the predominant model of genetic ero-sion, but rather through land-use change in themarginal environments of the tropics and sub-tropics that comprise a majority of the hypoth-esized global hot spots of biological diversityin agriculture. Agricultural disintensification,locally common amid globalization, is complexand multidirectional. It may either support orerode a prospective contribution of the biolog-ical diversity of agriculture to sustainability inthe context of future global change. Specificpolicies are needed for bolstering adaptivecapacities and resilience of marginal farmers,their communities, and other local institutionsalong with their biodiversity, agroecosystems,and food security. Supporting policies andgovernance initiatives must anticipate theimpacts and opportunities of dynamic landuse and global change involving the increasedmultiscale integration of combined agriculturalintensification and disintensification.

SUMMARY POINTS

1. The biological diversity of agriculture is coupled via bidirectional interaction as impactprocess and influential conditioner of global change.

2. Global change related to the biological diversity of agriculture is composed of global landuse and climate changes together with broad social-environmental changes (globalizationof agricultural development, market integration, technological change, and regulationthrough global treaties, policies, and institutional networks).

3. Interaction of the biological diversity of agriculture with processes of global change occursthrough the strongly mediating influences of management, scale, social-environmentaladaptation, adaptive capacity, vulnerability, and the resilience of farmers and land users.

4. Global change poses steep challenges and the prospect of significant negative impactson the biological diversity of agriculture. Sustainable use and successful conservationdepend on global policies, institutions, and politics capable of fully addressing agricul-ture and food issues as well as incorporating them in broadly defined development andsustainability.

5. Crosscutting relations exist between the biological diversity of agriculture involving prin-cipal analytic levels and major management scales (field, farm, community, multicom-munity, landscape and region, country) and aggregated effects at international and globalscales.


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


6. The focus of policy and practical studies has shifted from identifying threats to thecurrent emphasis on persistence, resilience, and flexibility in farmer varieties, landraces,and breeds and the importance of complex social-environmental and spatial dynamics ofagroecosystems and landscapes.

7. Policies are needed for building the adaptive capacities and resilience of marginal farmersand their communities, utilizing the biodiversity of their agroecosystems to enhance foodsecurity amid agricultural intensification and disintensification, acting either alone or inregionally integrated combinations.

8. Key to scientific and policy analysis of biological diversity in agriculture interactingwith global change is a framework of concepts across four areas: biological diversityin agriculture; global change processes; farm and land-use management and scale; andsocial-environmental adaptation, vulnerability, and resilience.

FUTURE ISSUES

1. What are the impacts and adaptive capacity of biological diversity in agriculture in relationto global change–driven agricultural intensification?

2. What are the impacts and adaptive capacity of biological diversity in agriculture in relationto expanding water resource management in responses to global change?

3. What are the impacts and adaptive capacity of biological diversity in small-scale agricul-ture and land use amid expanding pest and nutrient management associated with globalchange policies?

4. It is important to develop case studies of the biological diversity of agriculture amid theincreased integration of agricultural intensification and disintensification as a result oflinks among geographic areas and production and management factors (including labor,capital, and food and environmental policy).

5. It is necessary to improve the analytical and monitoring capacity of land change scienceand land-use-cover change approaches and their methods applied to biological diversityin agriculture.

6. How does the biological diversity of agriculture relate to capacities and thresholds ofadaptive capacity, vulnerability, and resilience in landscapes and regions representingglobal hot spots of biological diversity of agriculture?

7. Develop and test alternative or modified models of biodiversity loss and conservation inagriculture that investigate the relations of development and policies, e.g., the impacts ofpayment-for-environment-service and protected-area with sustainable-use approachesto conservation.

DISCLOSURE STATEMENT

The author is not aware of any affiliations, memberships, funding, or financial holdings that mightbe perceived as affecting the objectivity of this review.

158 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


ACKNOWLEDGMENTS

I thank for contributions and engagement in this research project Martha Bell, Bill Easterling,and Petra Tschakert at Penn State, Nina Jablonski and Peter Hudson of the campus-wide Geo-Genetics group, and Steve Brush, Kimberlee Chambers, Laura Lewis, Oliver Coomes, Jacobvan Etten, and Ernesto Mendez in sessions of the annual geography meetings in Boston (2008)and Las Vegas (2009). A draft version of this paper was presented in the Symposium on GeneticDiversity and Landscape Evolution held at the University of California, Davis, in September2008. Invaluable general input since 2000 was received from related field research with severalinstitutions and collaborators, including Luis Rojas, Teresa Hosse, Freddy Delgado, NelsonTapia, and Stephan Rist (Bolivia); Ramiro Ortega, Jorge Recharte, and Marıa Mayer (Peru);Daniel Debouck (Colombia); Elizabeth Veasy (Brazil); and Eduardo Santana, Enrique Jardel, andDominique Louette (Mexico). These field projects were funded through NSF BC 0240962, NSFHSD 0948816, and Penn State University as well as by the Kellett Faculty Award of the Universityof Wisconsin-Madison. Tom Tomich provided superb editorial guidance and feedback, andexcellent suggestions were received from Christine Padoch and Miguel Pinedo-Vasquez.

LITERATURE CITED

1. Lambin EF, Geist HJ, Lepers E. 2003. Dynamics of land-use and land-cover change in tropical regions.Annu. Rev. Environ. Resour. 28:205–41

2. Wood S, Ehui S. 2005. Food. In Ecosystems and Human Well-Being: Current State and Trends: Findings ofthe Condition and Trends Working Group, ed. R Hassan, R Scholes, N Ash, 8:209–39. Washington, DC:Island

3. Easterling WE, Aggarwal PK, Batima P, Brander KM, Erda L, et al. 2007. Food, fibre and forest products.See Ref. 167, pp. 273–313

4. McCarthy JJ, Canziani OF, Leary NA, Dokken DJ, White KS, eds. 2001. Climate Change 2001: Im-pacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Third Assessment Report of theIntergovernmental Panel on Climate Change. Cambridge, UK/New York: Cambridge Univ. Press. 1032pp.

5. Rosenzweig C, Casassa G, Karoly DJ, Imeson A, Liu C, et al. 2007. Assessment of observed changes andresponses in natural and managed systems. See Ref. 167, pp. 79–131

6. Johns T. 2007. Agrobiodiversity, diet and human health. See Ref. 168, pp. 382–4067. DeFries RS, Foley JA, Asner GP. 2004. Land use choices: balancing human needs and ecosystem function.

Front. Ecol. Environ. 2:249–578. Zimmerer KS. 2009. Biodiversity. In A Companion to Environmental Geography, ed. N Castree, D De-

meritt, D Liverman, B Rhoads, pp. 50–65. Malden, MA: Wiley- Blackwell. 588 pp.9. Loreau M, Naseem S, Inchausti P, Bengtsson J, Grime JP, et al. 2001. Biodiversity and ecosystem

functioning: current knowledge and future challenges. Science 294:804–810. Tuxill J. 2000. The biodiversity that people made. World Watch 13:25–3511. Altieri MA. 1999. The ecological role of biodiversity in agroecosystems. Agric. Ecosyst. Environ. 74:19–3112. Swift MJ, Izac A-MN, van Noordwijk M. 2004. Biodiversity and ecosystem services in agricultural

landscapes: Are we asking the right questions? Agric. Ecosyst. Environ. 104:113–3413. Vandermeer J, van Noordwijk M, Anderson J, Ong C, Perfecto I. 1998. Global change and multi-species

agroecosystems: concepts and issues. Agric. Ecosyst. Environ. 67:1–2214. Jackson MT, Ford-Lloyd BV. 1990. Plant genetic resources—a perspective. See Ref. 169, pp. 1–1715. Lipper L, Cooper D. 2009. Managing plant genetic resources for sustainable use in food and agriculture.

See Ref. 170, pp. 27–3916. Kontoleon A, Pascual U, Smale M. 2009. Introduction: Agrobiodiversity for economic development:

What do we know? See Ref. 170, pp. 1–2417. Wood D, Lenne JM. 1997. The conservation of agrobiodiversity on-farm: questioning the emerging

paradigm. Biodivers. Conserv. 6:109–29


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


18. Arriaga-Jordan CM, Pedraza-Fuentes AM, Nava-Bernal EG, Chavez-Mejia MC, Castelan-Ortega OA.2005. Livestock agrodiversity of Mazahua smallholder campesino systems in the highlands of centralMexico. Hum. Ecol. 33:821–45

19. Brookfield H. 2001. Exploring Agrodiversity. New York: Columbia Univ. Press. 348 pp.20. Liang LH, Stocking M, Brookfield H, Jansky L. 2001. Biodiversity conservation through agrodiversity.

Glob. Environ. Change 11:97–10121. Kennedy AC. 1999. Microbial diversity in agroecosystem quality. See Ref. 171, pp. 1–1822. Tinker B, Goudriaan J, Teng P, Swift M, Linder S, Ingram J. 1996. Global change impacts on agriculture,

forestry and soils: the programme of the global change and terrestrial ecosystems core project of IGBP.See Ref. 172, pp. 295–318

23. Leakey RRB, Tchoundjeu Z, Smith RI, Munro RC, Fondoun J-M, et al. 2004. Evidence that subsistencefarmers have domesticated indigenous fruits (Dacryodes edulis and Irvingia gabenensis) in Cameroon andNigeria. Agrofor. Syst. 60:101–11

24. Mendez VE, Gliessman SR, Gilbert GS. 2007. Tree biodiversity in farmer cooperatives of a shade coffeelandscape in western El Salvador. Agric. Ecosyst. Environ. 119:145–59

25. Duvall CS. 2006. On the origin of the tree Spondias mombin in Africa. J. Hist. Geogr. 32:249–6626. Michon G, de Foresta H, Levang P, Verdeaux F. 2007. Domestic forests: a new paradigm for integrating

local communities’ forestry into tropical forest science. Ecol. Soc. 12:127. Natl. Res. Counc. 2000. Global Change Ecosystems Research. Washington, DC: Natl. Acad. Press. 48 pp.28. Vitousek PM. 1994. Beyond global warming: ecology and global change. Ecology 75:1862–7529. Turner BL II, Skole D, Sanderson S, Fischer G, Fresco L, Leemans R. 1995. Land-Use and Land-Cover

Change. Science/Research Plan. Stockholm/Geneva: Int. Geosph.-Biosph. Program. (IGBP). 132 pp.30. Matson PA, Parton WJ, Power AG, Swift MJ. 1997. Agricultural intensification and ecosystem properties.

Science 277:504–931. Tilman D, Cassman KG, Matson PA, Naylor R, Polasky S. 2002. Agricultural sustainability and intensive

production practices. Nature 418:671–7732. Cleveland DA, Soleri D. 2002. Introduction: Farmers, scientists and plant breeding: knowledge, practice

and the possibilities for collaboration. In Farmers, Scientists and Plant Breeding: Integrating Knowledge andPractice, ed. DA Cleveland, D Soleri, pp. 1–18. New York: CABI Publ.

33. Harlan JR. 1992. Crops and Man. Madison, WI: Am. Soc. Agron. 295 pp.34. van Heerwaarden J, Hellin J, Visser RF, van Eeuwijk FA. 2009. Estimating maize genetic erosion in

modernized smallholder agriculture. Theor. Appl. Genet. 119:875–8835. Hodgkin T, Rana R, Tuxill J, Balma D, Subedi A, et al. 2007. Seed systems and crop genetic diversity in

agroecosystems. See Ref. 168, pp. 77–11636. Louette D. 1999. Traditional management of seed and genetic diversity: What is a landrace? See Ref.

173, pp. 109–4237. Arslan A, Taylor JE. 2009. Farmers’ subjective valuation of subsistence crops: the case of traditional

maize in Mexico. Am. J. Agr. Econ. 91:956–7238. Benz B, Perales H, Brush S. 2007. Tzeltal and Tzotzil farmer knowledge and maize diversity in Chiapas,

Mexico. Curr. Anthropol. 48:289–30039. Brush SB. 2004. Farmers’ Bounty: Locating Crop Diversity in the Contemporary World. New Haven/London:

Yale Univ. Press. 327 pp.40. Rhoades RE, Nazarea VD. 1999. Local management of biodiversity in traditional agroecosystems. See

Ref. 171, pp. 215–3641. Zimmerer KS. 1996. Changing Fortunes: Biodiversity and Peasant Livelihood in the Peruvian Andes. Berke-

ley/Los Angeles: Univ. Calif. Press. 308 pp.42. Jarvis DI, Padoch C, Cooper HD. 2007. Biodiversity, agriculture, and ecosystem services. See Ref. 168,

pp. 1–1243. Wood D, Lenne JM. 1999. Why agrobiodiversity? See Ref. 174, pp. 1–1444. Padoch C, Pinedo-Vasquez M. 2001. Resource management in Amazonia: Caboclo and ribereno tradi-

tions. In On Biocultural Diversity, ed. L Maffi, pp. 364–75. Washington, DC: Smithsonian Inst.45. Perales H, Brush SB, Qualset CO. 2003. Dynamic management of maize landraces in central Mexico.

Econ. Bot. 57:21–34

160 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


46. Thurston HD, Salick J, Smith ME, Trutmann P, Pham J-L, McDowell R. 1999. Traditional managementof agrobiodiversity. See Ref. 174, pp. 211–44

47. Ban N, Coomes OT. 2004. Home gardens in Amazonian Peru: diversity and exchange of plantingmaterial. Geogr. Rev. 94:348–67

48. Coomes OT, Ban N. 2004. Cultivated plant species diversity in home gardens of an Amazonian peasantvillage in northeastern Peru. Econ. Bot. 58:420–34

49. Perrault-Archambault M, Coomes OT. 2008. Distribution of agrobiodiversity in home gardens alongthe Corrientes River, Peruvian Amazon. Econ. Bot. 62:109–26

50. Rerkasem K, Lawrence D, Padoch C, Schmidt-Vogt D, Ziegler A, et al. 2009. Consequences of swiddentransitions for crop and fallow biodiversity in Southeast Asia. Hum. Ecol. 37:347–60

51. La Salle J. 1999. Insect biodiversity in agroecosystems: function, value and optimization? See Ref. 174,pp. 155–82

52. Wardle DA, Giller KE, Barker GM. 1999. The regulation and functional significance of soil biodiversityin agroecosystems. See Ref. 174, pp. 87–122

53. Barry MB, Pham JL, Courtois B, Billot C, Ahmadi N. 2007. Rice genetic diversity at farm and villagelevels and genetic structure of local varieties reveal need for in situ conservation. Genet. Resour. Crop Eval.54:1675–90

54. Drucker AG. 2007. Economics of livestock genetic resources conservation and sustainable use: state ofthe art. See Ref. 168, pp. 426–45

55. van Etten J, Fuentes Lopez MR, Monterroso LGM, Samayoa KMP. 2008. Genetic diversity of maize(Zea mays L. ssp mays) in communities of the western highlands of Guatemala: geographical patterns andprocesses. Genet. Resour. Crop Eval. 55:303–17

56. Gibson JP, Ayalew W, Hanotte O. 2007. Measures of diversity as inputs for decisions in conservation oflivestock genetic resources. See Ref. 168, pp. 117–40

57. Nuijten E, van Treuren R. 2007. Spatial and temporal dynamics in genetic diversity in upland rice andlate millet (Pennisetum glaucum (L.) R. Br.) in the Gambia. Genet. Resour. Crop Eval. 54:989–1009

58. Peroni N, Kageyama PY, Begossi A. 2007. Molecular differentiation, diversity, and folk classification of“sweet” and “bitter” cassava (Manihot esculenta) in Caicara and Caboclo management systems (Brazil).Genet. Resour. Crop Eval. 54:1333–49

59. Tiranti B, Negri V. 2007. Selective microenvironmental effects play a role in shaping genetic diversity andstructure in a Phaseolus vulgaris L. landrace: implications for on-farm conservation. Mol. Ecol. 16:4942–55

60. Veasey EA, Borges A, Rosa MS, Queiroz-Silva JR, Bressan EDA, Peroni N. 2008. Genetic diversityin Brazilian sweet potato (Ipomoea batatas (L.) Lam., Solanales, Convolvulaceae) landraces assessed withmicrosatellite markers. Genet. Mol. Biol. 31:725–33

61. Zimmerer KS. 1998. The ecogeography of Andean potatoes: versatility in farm regions and fields canaid sustainable development. BioScience 48:445–54

62. Caillon S, Quero-Garcia J, Lescure J-P, Lebot V. 2006. Nature of taro (Colocasia esculenta (L.) Schott)genetic diversity prevalent in a Pacific Ocean island, Vanua Lava, Vanuatu. Genet. Resour. Crop Evol.53:1273–89

63. Heywood V, Casas A, Ford-Lloyd B, Kell S, Maxted N. 2007. Conservation and sustainable use of cropwild relatives. Agric. Ecosyst. Environ. 121:245–55

64. Reilly J. 1996. Climate change, global agriculture and regional vulnerability. See Ref. 172, pp. 237–6665. Martınez-Castillo J, Zizumbo-Villarreal D, Gepts P, Colunga-GarciaMarin P. 2007. Gene flow and

genetic structure in the wild-weedy-domesticated complex of Phaseolus lunatus L. in its Mesoamericancenter of domestication and diversity. Crop Sci. 47:58–66

66. Jarvis DI, Hodgkin T. 1999. Wild relatives and crop cultivars: detecting natural introgression and farmerselection of new genetic combinations in agroecosystems. Mol. Ecol. 8:S159–73

67. McAfee C. 2004. Geographies of risk and difference in crop genetic engineering. Geogr. Rev. 94:80–10668. Hammer K, Laghetti G. 2005. Genetic erosion—examples from Italy. Genet. Resour. Crop. Evol. 52:629–

3469. Smith RG, Gross KL, Robertson GP. 2008. Effects of crop diversity on agroecosystem function: crop

yield response. Ecosystems 11:355–66


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


70. Niklaus PA. 2007. Climate change effects on biogeochemical cycles, nutrients, and water supply. SeeRef. 175, pp. 11–52

71. Brush SB. 1999. The issues of in situ conservation of crop genetic resources. See Ref. 173, pp. 3–2872. Brush SB, Perales HR. 2007. A maize landscape: ethnicity and agro-biodiversity in Chiapas Mexico.

Agric. Ecosyst. Environ. 121:211–2173. Duelli P. 1997. Biodiversity evaluation in agricultural landscapes: an approach at two different scales.

Agric. Ecosyst. Environ. 62:81–9174. Jackson LE, Pascual U, Hodgkin T. 2007. Utilizing and conserving agrobiodiversity in agricultural

landscapes. Agric. Ecosyst. Environ. 121:196–21075. Brookfield H, Padoch C. 2007. Managing biodiversity in spatially and temporally complex agricultural

landscapes. See Ref. 168, pp. 338–6176. Scherr SJ, McNeely JA. 2008. Biodiversity conservation and agricultural sustainability: towards a new

paradigm of ‘ecoagriculture’ landscapes. Philos. Trans. R. Soc. Lond. B 363:477–9477. Perfecto I, Vandermeer J. 2010. The agroecological matrix as alternative to the land-sparing/agriculture

intensification model. Proc. Natl. Acad. Sci. USA 107:5786–9178. Zimmerer KS. 2010. Woodlands and agrobiodiversity in irrigation landscapes amidst global change

(Bolivia, 1990–2002). Prof. Geogr. 62:335–5679. Di Falco S, Chavas J-P. 2008. Rainfall shocks, resilience, and the effects of crop biodiversity on agroe-

cosystem productivity. Land Econ. 84:83–9680. Ruiz Corral JA, Puga ND, Gonzalez JDS, Parra JR, Eguiarte DRG, et al. 2008. Climatic adaptation and

ecological descriptors of 42 Mexican maize races. Crop Sci. 48:1502–1281. Hijmans RJ, Garrett KA, Huaman Z, Zhang DP, Schreuder M, Bonierbale M. 2000. Assessing the

geographic representativeness of genebank collections: the case of Bolivian wild potatoes. Conserv. Biol.14:1755–65

82. Hijmans RJ, Spooner DM, Salas AR, Guarino L, de la Cruz J. 2002. Atlas of Wild Potatoes. Maccarese,Italy: Int. Plant Genet. Resourc. Inst. 130 pp.

83. Nabhan GP. 2009. Where Our Food Comes From: Retracing Nicolay Vavilov’s Quest to End Famine. Wash-ington, DC: Island. 223 pp.

84. Gomez JAA, Bellon MR, Smale M. 2000. A regional analysis of maize biological diversity in southeasternGuanajuato, Mexico. Econ. Bot. 54:60–72

85. Smale M, ed. 2006. Valuing Crop Biodiversity: On-Farm Genetic Resources and Economic Change. Cambridge,MA: CABI Publ. 318 pp.

86. Chambers KJ, Brush SB, Grote MN, Gepts P. 2007. Describing maize (Zea mays L.) landrace persistencein the Bajio of Mexico: a survey of 1940s and 1950s collection locations. Econ. Bot. 61:60–72

87. Smale M, Bellon MR, Gomez JAA. 2001. Maize diversity, variety attributes, and farmers’ choices insoutheastern Guanajuato, Mexico. Econ. Dev. Cult. Change 50:201–25

88. Mayer E, Glave M. 1999. Alguito para ganar (a little something to earn): profits and losses in peasanteconomies. Am. Ethnol. 26:344–69

89. van Dusen ME, Taylor JE. 2005. Missing markets and crop diversity: evidence from Mexico. Environ.Dev. Econ. 10:513–31

90. Chambers KJ, Momsen JH. 2007. From the kitchen and the field: gender and maize diversity in the Bajıoregion of Mexico. Singap. J. Trop. Geogr. 28:39–56

91. Jarvis DI, Brown AHD, Cuong PH, Collado-Panduro L, Latournerie-Moreno L, et al. 2008. A globalperspective of the richness and evenness of traditional crop-variety diversity maintained by farmingcommunities. Proc. Natl. Acad. Sci. USA 105:5326–31

92. Rerkasem K, Pinedo-Vasquez M. 2007. Diversity and innovation in smallholder systems in response toenvironmental and economic changes. See Ref. 168, pp. 362–81

93. Badstue LB, Bellon MR, Berthaud J, Juaarez X, Rosas IM, et al. 2006. Examining the role of collectiveaction in an informal seed system: a case study from the central valleys of Oaxaca, Mexico. Hum. Ecol.34:249–73

94. Bezancon G, Pham J-L, Deu M, Vigouroux Y, Sagnard F, et al. 2009. Changes in the diversity andgeographic distribution of cultivated millet (Pennisetum glaucum (L.) R. Br.) and sorghum (Sorghumbicolor (L.) Moench) varieties in Niger between 1976 and 2003. Genet. Resour. Crop. Evol. 56:223–36

162 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


95. van Etten J. 2006. Molding maize: the shaping of a crop diversity landscape in the western highlands ofGuatemala. J. Hist. Geogr. 32:689–711

96. Zimmerer KS. 2003. Geographies of seed networks for food plants (potato, ulluco) and approaches toagrobiodiversity conservation in the Andean countries. Soc. Nat. Resour. 16:583–601

97. Vitousek PM, Aber JD, Howarth RW, Likens GE, Matson PA, et al. 1997. Human alteration of theglobal nitrogen cycle: sources and consequences. Ecol. Appl. 7:737–50

98. Robertson GP, Vitousek PM. 2009. Nitrogen in agriculture: balancing the cost of an essential resource.Annu. Rev. Environ. Resour. 14:97–125

99. Rindfuss RR, Walsh SJ, Turner BL II, Fox J, Mishra V. 2004. Developing a science of land change:challenges and methodological issues. Proc. Natl. Acad. Sci. USA 101:13976–81

100. Adger WN, Paavola J, Huq S. 2006. Toward justice in adaptation to climate change. See Ref. 176, pp.1–19

101. Reece JD. 2007. Does genomics empower resource-poor farmers? Some critical questions and experi-ences. Agric. Syst. 94:553–65

102. Rosenzweig C, Parry ML. 1994. Potential impact of climate change on world food supply. Nature367:133–38

103. Rosenzweig C, Hillel D. 2008. Climate Variability and the Global Harvest: Impacts of El Nino and OtherOscillations on Agroecosystems. Oxford/New York: Oxford Univ. Press. 259 pp.

104. Tubiello FN, Soussana J-F, Howden SM. 2007. Crop and pasture response to climate change. Proc. Natl.Acad. Sci. USA 104:19686–90

105. Jarvis A, Lane A, Hijmans RJ. 2008. The effect of climate change on wild crop relatives. Agric. Ecosyst.Environ. 126:13–23

106. Mercer KL, Martınez-Vasquez A, Perales HR. 2008. Asymetrical local adaptation of maize landracesalong an altitudinal gradient. Evol. Appl. 1:489–500

107. Fuhrer J. 2003. Agroecosystem response to combinations of elevated CO2, ozone, and global climatechange. Agric. Ecosyst. Environ. 97:1–20

108. Patterson DT, Westbrook JK, Joyce RJV, Lingren PD, Gogasik J. 1999. Weeds, insects, and diseases.Clim. Change 43:711–27

109. Eur. Agric. Res. Dev. 2008. Climate Change: The Challenges for Agriculture. Brussels: Eur. Communities.35 pp.

110. Parry ML, Carter TR. 1990. An assessment of the effects of climatic change on agriculture. See Ref.169, pp. 61–84

111. Fuhrer J. 2007. Sustainability of crop production systems under climate change. See Ref. 175, pp. 167–85112. Howden SM, Soussana J-F, Tubiello FN, Chhetri N, Dunlop M, Meinke H. 2007. Adapting agriculture

to climate change. Proc. Natl. Acad. Sci. USA 104:19691–96113. Rosegrant MW, Cline SA. 2003. Global food security: challenges and policies. Science 302:1917–19114. Vasquez-Leon M, West CT, Finan TJ. 2003. A comparative assessment of climate vulnerability: agri-

culture and ranching on both sides of the US-Mexico border. Glob. Environ. Change 13:159–73115. Valentin C. 1996. Soil erosion under global change. In Global Change and Terrestrial Ecosystems, ed. B

Walker, W Steffen, pp. 317–40. Cambridge, UK/New York: Cambridge Univ. Press116. Lal R. 2009. Soils and food sufficiency. A review. Agron. Sustain. Dev. 29:113–33117. Brinkman R, Sombroek WG. 1996. The effects of global change on soil conditions in relation to plant

growth and food production. See Ref. 172, pp. 49–64118. Schlesinger WH. 1999. Carbon sequestration in soils. Science 284:2095119. Beddington J. 2010. Food security: contributions from science to a new and greener revolution. Philos.

Trans. R. Soc. Lond. B 365:61–71120. Eakin H, Luers AL. 2006. Assessing the vulnerability of social-environmental systems. Annu. Rev. En-

viron. Resour. 31:365–94121. Kates RW. 2000. Cautionary tales: adaptation and the global poor. Clim. Change 45:5–17122. Nelson DR, Adger WN, Brown K. 2007. Adaptation to environmental change: contributions of a re-

silience framework. Annu. Rev. Environ. Resour. 32:395–419123. O’Brien KL, Leichenko RM. 2000. Double exposure assessing the impacts of climate change within the

context of economic globalization. Glob. Environ. Change 10:221–32


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


124. Thomas DSG, Twyman C. 2006. Adaptation and equity in resource dependent societies. See Ref. 176,pp. 223–37

125. Turner BL II, Kasperson RE, Matson PA, McCarthy JJ, Corell RW, et al. 2003. A framework forvulnerability analysis in sustainability science. Proc. Natl. Acad. Sci. USA 100:8074–79

126. Challinor A, Wheeler T, Garforth C, Craufurd P, Kassam A. 2007. Assessing the vulnerability of foodcrop systems in Africa to climate change. Clim. Change 83:381–99

127. Dove MR. 2006. Indigenous people and environmental politics. Annu. Rev. Anthropol. 35:191–208128. Cruz RV, Harasawa H, Lal M, Wu S, Anokhin Y, et al. 2007. Asia. See Ref. 167, pp. 469–506129. Gregory PJ, Ingram JSI. 2000. Global change and food and forest production: future scientific challenges.

Agric. Ecosyst. Environ. 82:3–14130. Keleman A, Hellin J, Bellon MR. 2009. Maize diversity, rural development policy, and farmers’ practices:

lessons from Chiapas, Mexico. Geogr. J. 175:52–70131. Liverman DM, Vilas S. 2006. Neoliberalism and the environment in Latin America. Annu. Rev. Environ.

Resour. 31:327–63132. Vandermeer J, Perfecto I. 1995. Breakfast of Biodiversity: The Truth About Rain Forest Destruction. Oakland,

CA: Inst. Food Dev. Policy. 180 pp.133. Bellon MR, Adato M, Becerril J, Mindek D. 2006. Poor farmers’ perceived benefits from different types

of maize germplasm: the case of creolization in lowland tropical Mexico. World Dev. 34:113–29134. Soleri D, Cleveland DA, Cuevas FA. 2008. Food globalization and local diversity: the case of tejate. Curr.

Anthropol. 49:280–90135. Birol E, Smale M, Gyovai A. 2006. Using a choice experiment to estimate farmers’ valuation of agrobio-

diversity on Hungarian small farms. Environ. Resour. Econ. 34:439–69136. Wiskerke JSC, van der Ploeg JD, eds. 2004. Seeds of Transition: Essays on Novelty Production, Niches and

Regimes in Agriculture. Assen, Neth.: Van Gorcum. 356 pp.137. Keys E, McConnell WJ. 2005. Global change and the intensification of agriculture in the tropics. Glob.

Environ. Change 14:320–37138. Johns T, Eyzaguirre PB. 2006. Linking biodiversity, diet and health in policy and practice. Proc. Nutr.

Soc. 65:182–89139. Brush SB, Tadesse D, Van Dusen E. 2003. Crop diversity in peasant and industrialized agriculture:

Mexico and California. Soc. Nat. Resour. 16:123–41140. Dalrymple DG. 1988. Changes in wheat varieties and yields in the United States, 1919–1984. Agric. Hist.

62:20–36141. Matson PA, Vitousek PM. 2006. Agricultural intensification: Will land spared for farming be land spared

for nature? Conserv. Biol. 20:709–10142. Tomich TP, van Noordwijk M, Budidarsono S, Gillison A, Kusumanto T, et al. 2001. Agricultural

intensification, deforestation, and the environment: assessing trade-offs in Sumatra, Indonesia. In Trade-Offs or Synergies? Agricultural Intensification, Economic Development, and the Environment, ed. DR Lee, CBBarrett, pp. 221–44. Wallingford, UK: CABI Publ.

143. Di Falco S, Smale M, Perrings C. 2008. The role of agricultural cooperatives in sustaining the wheatdiversity and productivity: the case of southern Italy. Environ. Resour. Econ. 39:161–74

144. Evenson RE. 1999. Global and local implications of biotechnology and climate change for future foodsupplies. Proc. Natl. Acad. Sci. USA 96:5921–28

145. Engels JMM, Ebert AW, Thormann I, de Vicente MC. 2006. Centres of crop diversity and/or origin,genetically modified crops and implications for plant genetic resources conservation. Genet. Resour. CropEval. 53:1675–88

146. Bellon MR, Berthaud J. 2006. Traditional Mexican agricultural systems and the potential impacts oftransgenic varieties on maize diversity. Agric. Hum. Values 23:3–14

147. Soleri D, Cleveland DA, Cuevas FA. 2006. Transgenic crops and crop varietal diversity: the case of maizein Mexico. BioScience 56:503–13

148. Mercer KL, Wainwright JD. 2008. Gene flow from transgenic maize to landraces in Mexico: an analysis.Agric. Ecosyst. Environ. 123:109–15

149. Maxted N, Guarino L, Myer L, Chiwona EA. 2002. Towards a methodology for on-farm conservationof plant genetic resources. Genet. Resour. Crop Eval. 49:31–46

164 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


150. Wood D, Lenne JM. 2005. ‘Received wisdom’ in agricultural land use policy: 10 years on from Rio. LandUse Policy 22:75–93

151. Bellon MR. 2009. Do we need crop landraces for the future? Realizing the global value of in situconservation. See Ref. 170, pp. 51–61

152. Gepts P. 2006. Plant genetic resources conservation and utilization: the accomplishments and future ofa societal insurance policy. Crop Sci. 46:2278–92

153. Smale M, Hazell P, Hodgkin T, Fowler C. 2009. Do we have an adequate strategy for securing thebiodiversity of major food crops? See Ref. 170, pp. 40–50

154. Zimmerer KS, ed. 2006. Globalization and New Geographies of Conservation. Chicago: Univ. Chicago Press155. Nabhan GP. 2007. Agrobiodiversity change in a Saharan desert oasis, 1919–2006: historic shifts in

Tasiwit (Berber) and Bedouin crop inventories of Siwa, Egypt. Econ Bot. 61:31–43156. Almekinders CJM, Humphries S, von Lossau A. 2008. The effectiveness of participatory plant breeding

as a tool to capitalize on agrobiodiversity in developing countries. Biodiversity 9:41–44157. Cleveland DA, Soleri D. 2007. Extending Darwin’s analogy: bridging differences in concepts of selection

between farmers, biologists, and plant breeders. Econ. Bot. 61:121–36158. Collins WW, Hawtin GC. 1999. Conserving and using crop plant biodiversity in agroecosystems. See

Ref. 171, pp. 267–82159. Witcombe J, Virk D, Farrington J, eds. 1998. Seeds of Choice: Making the Most of New Varieties for Small

Farmers. London: Intermed. Technol. 271 pp.160. Rice EB, Smith ME, Mitchell SE, Kresovich S. 2006. Conservation and change: a comparison of in situ

and ex situ conservation of Jala maize germplasm. Crop. Sci. 46:428–36161. Meilleur BA, Hodgkin T. 2004. In situ conservation of crop wild relatives: status and trends. Biodivers.

Conserv. 13:663–84162. Schroder S, Begemann F, Harret S. 2007. Agrobiodiversity monitoring—documentation at European

level. J. Verbrauch. Lebensm. 1:29–32163. Dyer GA, Taylor JE. 2008. A crop population perspective on maize seed systems on Mexico. Proc. Natl.

Acad. Sci. USA 105:470–75164. Smale M, Singh J, Di Falco S, Zambrano P. 2008. Wheat breeding, productivity and slow variety change:

evidence from the Punjab of India after the Green Revolution. Aust. J. Agric. Resour. Econ. 52:419–32

165. Clement CR. 1999. 1492 and the loss of Amazonian crop genetic resources. II. Crop biogeography atcontact. Econ. Bot. 53:203–16

166. Schmidt MR, Wei W. 2006. Loss of agro-biodiversity, uncertainty, and perceived control: a comparativerisk perception study in Austria and China. Risk Anal. 26:455–70

167. Parry ML, Canziani OF, Palutikof JP, Van Der Linden PJ, Hanson CE, eds. 2007. Climate Change2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change. Cambridge, UK/New York: Cambridge Univ.Press

168. Jarvis DI, Padoch C, Cooper HD, eds. 2007. Managing Biodiversity in Agricultural Ecosystems. New York:Columbia Univ. Press

169. Jackson MT, Ford-Lloyd BV, Parry ML, eds. 1990. Climatic Change and Plant Genetic Resources. NewYork: Belhaven

170. Kontoleon A, Pascual U, Smale M, eds. 2009. Agrobiodiversity, Conservation and Economic Development.London/New York: Routledge. 464 pp.

171. Collins WW, Qualset CO, eds. 1999. Biodiversity in Agroecosystems. New York: CRC Press172. Bazzaz F, Sombroek W, eds. 1996. Global Climate Change and Agricultural Production: Direct and In-

direct Effects of Changing Hydrological Pedological and Plant Physiological Processes. Rome/New York: UNFAO/Wiley

173. Brush SB, ed. 1999. Genes in the Field: On-Farm Conservation of Crop. Rome: Int. Plant Genet. Resour.Inst.

174. Wood D, Lenne JM. 1999. Agrobiodiversity Characterization, Utilization and Management. New York:CABI Publ.


Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


175. Newton PCD, Carran RA, Edwards GR, Niklaus PA, eds. 2007. Agroecosystems in a Changing Climate.New York: CRC Press

176. Adger WN, Paavola J, Huq S, Mace MJ, eds. 2006. Fairness in Adaptation to Climate Change. Cambridge,MA: MIT Press

177. Vavilov NI. 2009. Origin and Geography of Cultivated Plants. Cambridge, UK: Cambridge Univ. Press.500 pp.

166 Zimmerer

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.


Agr

odiv

ersi

ty

Agro

biod

iver

sity

Crop

and

live

stoc

k di

vers

ity

Crop

and

live

stoc

k ge

netic

reso

urce

s

Agro

ecos

yste

ms

Biod

iver

sity

/bio

logi

cal d

iver

sity

and

agric

ultu

re/

agro

ecos

yste

ms

Glo

bal c

hang

e/gl

obal

clim

ate

chan

ge a

nd a

gric

ultu

re/

agro

ecos

yste

ms

2,50

0

2,00

0

1,50

0

1,00

0

500 0

Figu

re1

Rap

idgr

owth

ofsc

ient

ific

rese

arch

liter

atur

ein

maj

orto

pica

lsub

field

s(s

eele

gend

).T

heve

rtic

alax

isre

pres

ents

num

ber

ofar

ticle

spu

blis

hed.

www.annualreviews.org • Agrobiodiversity and Global Change C-1

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.

EG35-FM ARI 18 September 2010 7:49

Annual Review ofEnvironmentand Resources

Volume 35, 2010 Contents

Preface � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �v

Who Should Read This Series? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �vii

I. Earth’s Life Support Systems

Human Involvement in Food WebsDonald R. Strong and Kenneth T. Frank � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 1

Invasive Species, Environmental Change and Management, and HealthPetr Pysek and David M. Richardson � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �25

Pharmaceuticals in the EnvironmentKlaus Kummerer � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �57

II. Human Use of Environment and Resources

Competing Dimensions of Energy Security: An InternationalPerspectiveBenjamin K. Sovacool and Marilyn A. Brown � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �77

Global Water Pollution and Human HealthRene P. Schwarzenbach, Thomas Egli, Thomas B. Hofstetter, Urs von Gunten,

and Bernhard Wehrli � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 109

Biological Diversity in Agriculture and Global ChangeKarl S. Zimmerer � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 137

The New Geography of Contemporary Urbanization and theEnvironmentKaren C. Seto, Roberto Sanchez-Rodrıguez, and Michail Fragkias � � � � � � � � � � � � � � � � � � � � � 167

Green Consumption: Behavior and NormsKen Peattie � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 195

viii

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.

EG35-FM ARI 18 September 2010 7:49

III. Management, Guidance, and Governance of Resources and Environment

Cities and the Governing of Climate ChangeHarriet Bulkeley � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 229

The Rescaling of Global Environmental PoliticsLiliana B. Andonova and Ronald B. Mitchell � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 255

Climate RiskNathan E. Hultman, David M. Hassenzahl, and Steve Rayner � � � � � � � � � � � � � � � � � � � � � � � � � 283

Evaluating Energy Efficiency Policies with Energy-Economy ModelsLuis Mundaca, Lena Neij, Ernst Worrell, and Michael McNeil � � � � � � � � � � � � � � � � � � � � � � � � � 305

The State of the Field of Environmental HistoryJ.R. McNeill � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 345

Indexes

Cumulative Index of Contributing Authors, Volumes 26–35 � � � � � � � � � � � � � � � � � � � � � � � � � � � 375

Cumulative Index of Chapter Titles, Volumes 26–35 � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 379

Errata

An online log of corrections to Annual Review of Environment and Resources articles maybe found at http://environ.annualreviews.org

Contents ix

Ann

u. R

ev. E

nvir

on. R

esou

rc. 2

010.

35:1

37-1

66. D

ownl

oade

d fr

om w

ww

.ann

ualr

evie

ws.

org

by P

enns

ylva

nia

Stat

e U

nive

rsity

on

08/2

5/12

. For

per

sona

l use

onl

y.

biological diversity in agriculture and global change

Documents