Putting People in the Map: Anthropogenic Biomes of the World
Author(s): Erle C. Ellis and Navin Ramankutty
Reviewed work(s):
Source: Frontiers in Ecology and the Environment, Vol. 6, No. 8 (Oct., 2008), pp. 439-447
Published by: Ecological Society of America
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CONCEPTS
AND
QUESTIONS
in the map:
Putting
people
biomes
of the world
anthropogenic
Erle C Ellisl* andNavin Ramankuty2
Humans have fundamentallyalteredglobal patternsof biodiversityand ecosystemprocesses.Surprisingly,
existing systems for representingthese global patterns, includingbiome classifications,either ignore
humans altogetheror simplifyhuman influenceinto,atmost, fourcategories.Here,we present the first
biomes based on global patternsof sustained,directhuman interaction
characterizationof terrestrial
with
ecosystems.Eighteen "anthropogenicbiomes"were identifiedthroughempiricalanalysisof global popula
tion, land use, and
land cover. More
than 75% of Earth's
ice-free land showed
evidence
of alteration
as a
resultof human residenceand land use,with less than a quarter remainingas wildlands, supportingjust
11% of terrestrial
net primaryproduction.Anthropogenicbiomes offera newway forwardby acknowledg
inghuman influenceon global ecosystemsand moving us towardmodels and investigationsof the terres
trialbiosphere that integrate
human and ecological systems.
Front Ecol Environ 2008; 6(8): 439-447, doi: 10.1890/070062
Humans
have long distinguishedthemselvesfrom
other species by shaping ecosystem form and
processusing tools and technologies,such as fire,that
are beyond the capacity of other organisms (Smith
2007). This exceptionalabilityforecosystemengineer
inghas helped to sustainunprecedentedhumanpopula
tiongrowthover thepasthalfcentury,to suchan extent
thathumansnow consumeabout one-thirdof all terres
trialnet primary
production(NPP; Vitousek et al. 1986;
Imhoffet al. 2004) and move more earth and produce
more reactive nitrogen than all other terrestrial
processes combined (Galloway 2005; Wilkinson and
McElroy 2007). Humans are also causingglobal extinc
tions (Novacek and Cleland 2001) and changes in cli
mate thatare comparableto anyobservedin thenatural
record (Ruddiman 2003; IPCC 2007). Clearly,Homo
sapienshas emergedas a forceofnature rivalingclimatic
In a nutshell:
*Anthropogenic biomes offera new view of the terrestrial
bios
phere in itscontemporary,
human-alteredform
*Most of the terrestrial
biospherehas been alteredbyhuman res
idenceand agriculture
* Less thana quarterofEarth's ice-freeland iswild; only 20% of
this isforestsand > 36% isbarren
*More than 80% of all people live in denselypopulated urban
and village biomes
*Agriculturalvillages are themost extensiveof all denselypop
ulated biomes and one in fourpeople lives in them
'DepartmentofGeography and EnvironmentalSystems,University
ofMaryland, Baltimore,MD *(ece(umbc.edu); 2Departmentof
Geography and Earth SystemScience Program,McGill University,
Montreal, QC, Canada
C)TheEcological
Society
of
America
and geologic forcesin shaping the terrestrial
biosphere
and itsprocesses.
Biomes are themost basic units thatecologistsuse to
describe global patterns of ecosystem form,process,
and biodiversity.
Historically,biomes have been iden
tifiedandmapped based on generaldifferencesinveg
etation typeassociatedwith regionalvariations in cli
mate (Udvardy 1975;Matthews 1983; Prentice et al.
1992; Olson et al. 2001; Bailey 2004). Now that
humans have restructured
the terrestrial
biosphere for
and other uses, global patternsof
agriculture,forestry,
species compositionand abundance, primaryproduc
and thebiogeochemical
tivity,land-surface
hydrology,
cycles of carbon, nitrogen,and phosphorus,have all
been substantially altered (Matson et al. 1997;
Vitousek etal. 1997; Foley et al. 2005). Indeed, recent
studies indicate that human-dominated ecosystems
now covermore ofEarth's land surfacethando "wild"
ecosystems(McCloskey and Spalding 1989; Vitousek
et al. 1997; Sanderson et al. 2002,Mittermeier et al.
2003; Foley et al. 2005).
It is therefore
thatexistingdescriptionsof
surprising
biome systems
eitherignorehuman influencealtogether
or describeitusingatmost fouranthropogenic
ecosystem
classes (urban/built-up,
cropland,and one or twocrop
vegetationmosaic(s); classificationsystems
land/natural
include IGBP, Loveland et al. 2000; "Olson Biomes",
Olson et al. 2001; GLC 2000, Bartholomeand Belward
2005; andGLOBCOVER, Defournyet al. 2006). Here,
we presentan alternateview of the terrestrial
biosphere,
based on an empiricalanalysisof global patternsof sus
taineddirecthuman interaction
with ecosystems,
yield
ing a globalmap of "anthropogenicbiomes".We then
biomes to serve
examine thepotentialof anthropogenic
as a new global framework
forecology,completewith
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Anthropogenic
biomesof theworld
testablehypotheses,thatcan advance research,educa
tion,and conservationof the terrestrial
biosphereas it
existstoday- theproductof intensivereshaping
bydirect
interactions
with humans.
* Human interactions
with ecosystems
EC Ellis andN Ramankutty
("populated",1 to 10 personskm-2),and inconsequential
population("remote",< 1 personkm2). Populationclass
namesaredefinedonly in thecontextof thisstudy.
* Identifying
anthropogenicbiomes: an empirical
approach
Human interactionswith ecosystemsare inherently We identified
andmapped anthropogenicbiomesusing
the multi-stage empirical procedure detailed in
dynamicand complex (Folke et al. 1996; DeFries et al.
2004; Rindfusset al. 2004); anycategorization
of these is WebPanel 1 and outlinedbelow,basedon globaldata for
a grossoversimplification.
Yet there is littlehope of population(urban,non-urban),landuse (percentarea of
understandingand modeling these interactionsat a
pasture,crops,irrigation,
rice,urban land),and landcover
global scale without such simplification.
Most global (percentareaof treesand bareearth);data for
NPP, IGBP
models of primaryproductivity,
land cover,and Olson biomeswere obtained for later
species diversity,and
even climatedependon stratifying
the terrestrial
surface analysis (WebPanel 1 includes referencesforall data
into a limitednumberof functionaltypes,land-cover sources).Biome analysiswas conductedat 5 arcminute
types,biomes, or vegetation classes (Haxeltine and
resolution(5' gridcells cover -86 km2at theequator),a
Prentice1996;Thomas etal. 2004; Feddemaetal. 2005).
spatialresolutionselectedas thefinestallowingdirectuse
Human interactions
with ecosystemsrange fromthe of high-qualityland-usearea estimates.First,"anthro
relativelylightimpactsofmobile bandsofhunter-gather pogenic"5' cellswere separatedfrom"wild"cells,based
ers to the complete replacementof pre-existingecosys on thepresenceofhumanpopulations,crops,orpastures.
temswith built structures
(Smil 1991). Populationden
Anthropogeniccellswere thenstratified
intothepopula
of theformand intensity
of these tiondensityclassesdescribedabove ("dense","residen
sityisa usefulindicator
interactions,
as increasingpopulationshave longbeen
tial","populated",and "remote"),based on thedensityof
consideredboth a cause and a consequenceof ecosystem theirnon-urbanpopulation.
We thenused clusteranaly
modification to produce food and other necessities sis,a statistical
an optimal
proceduredesignedto identify
(Boserup1965, 1981;Smil 1991;Netting 1993). Indeed, numberof distinctnaturalgroupings(clusters)within a
most basic historicalformsofhuman-ecosysteminterac dataset (usingSPSS 15.01), to identify
naturalgroupings
tionare associatedwithmajor differences
inpopulation within the cells of each population densityclass and
density,includingforaging(< 1 person km-2),shifting within thewild class, based on non-urbanpopulation
(> 10 personskm-2),and continuouscultivation(> 100 densityand percenturbanarea,pasture,crops,irrigated,
persons km-2);populationsdenser than 2500 persons rice, trees,and bare earth. Finally, the strataderived
km-2arebelieved tobe unsupportable
by traditional
sub
abovewere described,labeled,and organizedintobroad
sistenceagriculture(Smil 1991;Netting 1993).
logicalgroupings,based on theirpopulations,land-use
In recentdecades, industrialagricultureand modern and land-covercharacteristics,
and theirregionaldistrib
have creatednew forms
ofhuman-ecosys ution,yieldingthe 18 anthropogenicbiome classes and
transportation
teminteraction
acrossthefullrangeofpopulationdensi
threewild biome classes illustratedin Figure 1 and
from
exurban
ties,
low-density
developmentsto vast describedinTable 1. (WebTables 1 and 2 providemore
conurbationsthatcombinehigh-density
cities, low-den detailedstatistics;
WebPanel 2 providesmaps viewable in
and even forestedareas (Smil Google Earth,GoogleMaps, andMicrosoftVirtualEarth,
sitysuburbs,agriculture,
a printable
1991;Qadeer 2000;Theobald 2004).Nevertheless,popu
wallmap, andmap data inGIS format.)
lationdensitycan stillserveas a usefulindicatorof the
formand intensityof human-ecosysteminteractions * A tour of the anthropogenic biomes
withina specificlocale,especially
when populationsdiffer
byan orderofmagnitudeormore.Suchmajor differences When viewedglobally,
biomesclearlydom
anthropogenic
in populationdensityhelp to distinguishsituationsin inatethe terrestrial
more than three
biosphere,covering
which humansmay be considered
merelyagentsofecosys quartersofEarth's ice-freelandand incorporating
nearly
tem transformation
90% of terrestrial
NPP and 80% of global treecover
(ecosystemengineers),fromsitua
tions inwhich human populationshave growndense
(Figures1 and 2a;WebTable 2). About halfof terrestrial
enough thattheirlocal resourceconsumptionandwaste NPP and landwere presentin theforested
and rangeland
productionforma substantial
componentof localbiogeo
biomes,which have relativelylow populationdensities
chemicalcyclesand otherecosystemprocesses.To begin andpotentiallylow impactsfromlanduse (excludingresi
our analysis,we therefore
categorizehuman-ecosystem dentialrangelands;
Figures1 and 2a). However,one-third
interactionsintofourclasses,based on major differences ofEarth's ice-freelandand about45% of terrestrial
NPP
inpopulationdensity:highpopulationintensity
("dense", occurredwithin cultivatedand substantially
populated
>100 persons km-2), substantialpopulation intensity biomes (dense settlements,
villages,croplands,and resi
("residential",
10 to 100 personskm-2),
minorpopulation dentialrangelands;
Figures1and 2a).
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Society ofAmerica
biomesof theworld
Anthropogenic
EC EllisandN Ramankutty
-E
3
Anthropogenic biomes: % world regions
Anthropogenic biomes: legend
Dense settlements
* 11 Urban
M 12 Dense settlements
_
- _oog
-
Forested
2.;;=
51 Populated forests
52 Remote forests
Villages
_
M 21 Rice villages
,122 Irrigated
villages
23 Croppedand pastoralvillages
24 Pastoral villages
* 25 Rainfed villages
U 26 Rainfedmosaic villages
Croplands
31 Residential irrigated
cropland
mosaic
32 Residential rainfed
33 Populated irrigated
cropland0=
34 Populated rainfedcropland
35 Remote croplands
100%
Rangelands
41 Residential rangelands
42 Populated rangelands
43 Remoterangelands
Wildlands
61Wild forests
62 Sparse trees
f\/
Region boundary
-
50% -
World
N.Amernca,
America,Afnca
Europe, Asia, Eurasia Near Latin
Austr.,
NZ developedOceania developing East Caribbean
intogroups(Table1),andsortedinorderof
areas. Biomesareorganized
map and regional
biomes:
world
Figure1.Anthropogenic
=
(5'= 0.0833').
5 arcminuteresolution
(geographic),
density.
Map scale 1:160000000, PlateCarreeprojection
population
of
this
map.
versions
interactive
biomeareasaredetailedinWebTable3;WebPanel2 provides
Regional
land (crops
while agricultural
40% live in just2% of theirtotalextent,
Of Earth's6.4 billionhuman inhabitants,
dense settlements
biomes (82% urbanpopulation),40% and pasture)averaged> 60% of theirarea.More than
live invillagebiomes (38% urban),15% live incropland 39% of denselypopulatedbiomeswere located inAsia,
more than60% of thatconti
biomes (7% urban), and 5% live in rangelandbiomes which also incorporated
(5% urban; forested
biomeshad 0.6% of global popula nent's totalglobal area,even thoughthisregionwas the
tion;Figure2a). Thoughmost people live indense settle fifthlargestof seven regions(Figure 1;WebTable 3).
ments and villages,thesecover just7% ofEarth'sice-free Village biomesweremost common inAsia, where they
land,and about60% of thispopulation isurban,livingin coveredmore thana quarterof all land.Africawas sec
the cities and townsembeddedwithin these biomes, ond,with 13% of villagebiome area, thoughthesecov
which also includealmostall of the landwe have classi ered just6% ofAfrica'sland.The most intensiveland-use
located in thevil
althoughthis is practiceswere also disproportionately
fiedas urban (94% of 0.5 million kmi2,
abouthalf theworld'sirrigated
land
probablya substantialunderestimate;Salvatore et al. lagebiomes,including
ofglobal riceland
(1.4of 2.7millionkM2)and two-thirds
2005; Figure2a).
popula
dense agricultural
(1.1 of 1.7millionkM2;Figure2a).
Village biomes,representing
After rangelands,cropland biomeswere the second
were by farthemost extensiveof thedenselypopu
tions,
latedbiomes,covering7.7 million kiM2,comparedwith most extensiveof the anthropogenicbiomes, covering
about20% ofEarth'sice-freeland.Far frombeing simple,
bio
1.5million km2fortheurbanand dense settlements
mes.Moreover,villagebiomeshouseaboutone-halfof the crop-coveredlandscapes,croplandbiomeswere mostly
world'snon-urbanpopulation (1.6 of -3.2 billion per mosaics of cultivatedlandmixedwith treesand pastures
only
croplandbiomesconstituted
sons).Though aboutone-thirdofglobalurbanarea isalso (Figure3c). As a result,
more thanhalfof theworld's totalcrop-covered
embedded
within thesebiomes,urbanareasaccountedfor slightly
Society
of
America
CThe
Ecological
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Anthropogenic
biomesof theworld
I
EC EllisandN Ramankutty
Table 1.Anthropogenic biome descriptions
Group
Biome
Description
Dense settlements
I I Urban
12 Dense settlements
Dense settlements
withsubstantial
urbanarea
Dense builtenvironments
withveryhighpopulations
Dense mixof ruralandurbanpopulations,
including
bothsuburbsandvillages
Villages
21 Rice villages
22 Irrigated
villages
Dense agricultural
settlements
Villagesdominatedbypaddyrice
Villagesdominatedby irrigated
crops
23
Cropped
and pastoral
villages
24 Pastoralvillages
25 Rainfedvillages
26
Rainfed mosaic
villages
Villages with a mix of crops and pasture
Villagesdominatedbyrangeland
Villagesdominatedbyrainfed
agriculture
Villages with a mix of trees and crops
Croplands
31 Residentialirrigated
cropland
mosaic
32 Residentialrainfed
Annualcrops
mixedwithotherlandusesand landcovers
Irrigated
with substantial
humanpopulations
cropland
Rangeland
4 1 Residentialrangelands
42 Populatedrangelands
43 Remote rangelands
Livestock
minimal
cropsand forests
grazing;
withsubstantial
humanpopulations
Rangelands
Rangelands
withminorhumanpopulations
Rangelands
with inconsequential
humanpopulations
Forested
5 I Populatedforests
52 Remote forests
withhumanpopulations
Forests
andagriculture
Forestswithminorhumanpopulations
Forestswith inconsequential
humanpopulations
Wildlands
61 Wild forests
oragriculture
Landwithout
humanpopulations
High treecover,
mostlyborealand tropicalforests
Mix of treesand rainfed
cropland
withsubstantial
human
populations
33 Populatedirrigated
cropland Irrigated
cropland
withminorhumanpopulations
34 Populatedrainfed
cropland Rainfedcropland
withminorhumanpopulations
35 Remotecroplands
humanpopulations
Croplandwith inconsequential
sus 16.0 billion tonsper year).
This may be explained by the
lower productivityof boreal
forests,
which predominate in
theforested
biomes,while crop
land biomes were located in
some of theworld'smost pro
ductiveclimatesand soils.
Wildlandswithoutevidenceof
human occupationor land use
occupiedjust22% ofEarth'sice
freeland in thisanalysis.In gen
eral, thesewere located in the
leastproductiveregionsof the
world;more than two-thirds
of
theirareaoccurredinbarrenand
As
sparselytree-covered
regions.
a result,even thoughwildlands
containedabout 20% cover by
wild forests(amix of borealand
tropicalforests;
Figure2c), wild
lands as a whole contributed
only about 11% of total terres
trial
NPP.
* Anthropogenicbiomes are
mosaics
It isclearfromthebiomedescrip
tionsabove, fromthe land-use
63 Barren
No treecover,
mostlydesertsand frozenland
and land-cover
patternsinFigure
3c, andmostof all,bycomparing
area (8 of 15million km'),with villagebiomeshosting our biomemap againsthigh-resolution
satelliteimagery
nearlya quarterand rangelandbiomesabout 16%. The
biomesarebestcharac
(WebPanel2), thatanthropogenic
croplandbiomesalso included17% of theworld'spasture terizedas heterogeneouslandscapemosaics,combininga
land,alongwith a quarterofglobal treecoverand nearly varietyofdifferent
landusesand landcovers.Urban areas
NPP. Most abundant inAfrica and are embeddedwithin agricultural
a thirdof terrestrial
areas, treesare inter
Asia, residential,rainfedmosaic was by far themost spersed
with croplandsand housing,andmanagedvegeta
extensivecroplandbiomeand thesecondmost abundant tion ismixedwith semi-natural
vegetation(eg croplands
biome overall (16.7 million km2),providinga home to areembedded
withinrangelands
and forests).
Though some
nearly600 million people, 4 million km2of crops,and of thisheterogeneity
mightbe explainedby the relatively
about 20% of theworld's treecoverandNPP - a greater coarse resolution
of our analysis,
we suggesta more basic
sharethantheentirewild forests
biome.
explanation:thatdirectinteractions
betweenhumansand
Rangeland biomeswere themost extensive,covering ecosystems
generallytakeplacewithinheterogeneous
land
nearlya thirdof global ice-freeland and incorporating scapemosaics (PickettandCadenasso 1995;Daily 1999).
73% of global pasture(28 million kM2),but thesewere Further,
we propose that thisheterogeneity
has three
foundprimarily
inaridandotherlowproductivity
regions causes,twoofwhich areanthropogenic
and all ofwhich are
with a highpercentageofbare earthcover (around50%;
fractalinnature(Levin 1992), producingsimilarpatterns
Figure3c). As a result,rangelands
fromthelandholdingsof indi
accountedforlessthan acrossspatialscalesranging
15% of terrestrial
NPP, 6% ofglobal treecover,and 5% of vidualhouseholdsto theglobalpatterning
of theanthro
globalpopulation.
pogenic biomes.
Forestedbiomescoveredan area similarto thecropland We hypothesizethateven in themost denselypopu
biomes (25million km2versus27 million km2forcrop
latedbiomes,most landscapeheterogeneityiscaused by
amuch greatertree-covered
lands),but incorporated
area naturalvariationin terrain,
hydrology,
soils,disturbance
(45% versus25% of theirglobal area). It is therefore
sur
regimes(eg fire),and climate,as describedby conven
prisingthat the totalNPP of the forestedbiomeswas
tionalmodels of ecosystems
and the terrestrial
biosphere
nearlythesameas thatof thecroplandbiomes (16.4 ver
(eg Levin 1992;Haxeltine and Prentice1996;Olson et
62
Sparse
trees
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Low tree cover, mostly cold and arid lands
i The Ecological
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Society ofAmerica
EC EllisandN Ramankutty
Anthropogenic
biomesof theworld
al. 2001). Anthropogenicenhancementof
naturallandscapeheterogeneity
represents
a secondarycause of heterogeneity
within
anthropogenicbiomes, explained in part
by thehuman tendencyto seek out and
use themost productivelandsfirstand to
workand populate theselandsmost inten
sively (Huston 1993). At a global scale,
thisprocessmay explainwhywildlandsare
most common in thosepartsof thebios
pherewith the leastpotentialforagricul
ture(ie polar regions,
mountains, low fer
tilitytropicalsoils;Figure1) andwhy,at a
given percentage of tree cover, NPP
appearshigher in anthropogenicbiomes
withhigherpopulationdensities(compare
NPP with tree cover, especially in wild
forests
versusforested
biomes;Figure3c).
Itmay also explainwhymosthumanpopu
lations,both urbanand rural,appear tobe
associatedwith intensiveagriculture(irri
gated crops, rice), and not with pasture,
or other, less intensiveland uses
forests,
(Figure3c). Finally,thishypothesis
explains
whymost fertile
valleysand floodplainsin
favorableclimates are already in use as
croplands,
while neighboring
hillslopesand
mountainsareoftenislandsof semi-natural
vegetation, leftvirtuallyundisturbedby
local populations (Huston 1993; Daily
1999).The thirdcauseof landscapehetero
geneityinanthropogenic
biomes isentirely
anthropogenic:humans create landscape
heterogeneity
as exemplified
directly,
by the
construction
of settlements
and transporta
tionsystemsinpatternsdrivenasmuch by
culturalas by environmentalconstraints
(PickettandCadenasso 1995).
All threeof thesedriversofheterogene
ityundoubtedlyinteractinpatterningthe
terrestrial
biosphere, but their relative
rolesat global scaleshave yet tobe studied
and surelymerit furtherinvestigation,
consideringthe impactsof landscapefrag
mentationon biodiversity(Vitouseket al.
1997;Sandersonetal. 2002).
* A conceptual model for
anthropogenicbiomes
(a)
100
World
total
-
Urban
Dense settlements
Rice villages
villages
Irrigated
Croppedandpastoralvillages
Pastoralvillages
Rainfedvillages
Rainfed
mosaic villages
tot~~~~~~~~~~~~~~~~~~~~~~Rs~talrifdmosaic
-
-
PopdationLand NPP Trees Bare Urban Rice Irigated
CropsPasture
Landcover
\
I
Populatedinited cropland
Remotecroplands
RessdenIalrangelands
Populatedrangelands
Remoterangjelands
Populatedforests
Renoteforests
?Wild forests
Sparsees
Landuse
(b)
Biome
AlI land
IGIBIP
classes
a i
Snow
or
Barren
sparsely
vegetated
Deciduousreedleleafforest
shrublands
Grassls
Mixed Evergreen
Open
d
forests broadleafforest
Urbanand
Savannas
Evergreen
forest Woodysavannas Permanent
needleleaf
wetlans
built-up
Deciduousbroadleaf
forest Cropl1natural
Closed shrublandsvegetation saic
Biome
All land
Olson Biomes
Tundra
Bo
J forests D
and
xeric
shubb /
e
o r cbiomeis
TFue2
xrests
Tj
sbtoi
rd
moist
as farenta
ad sub
Tmpiral
95sla, saai,
s
and
subtro
gbal
savm
grasads and
Fbooded
Twil mixd
nteWs //af
otae grasslwds
and
/tw
TiaW
ires /s
Meditmae forests,
and
shnbland
woodlands,
Noadleafa
dry
Twerpate
s
grasslains,
savw, and
T
and
cboniferou
forests
Figure 2. Anthropogerucbiomes expressedas a percentageof (a) global population
ice-free
land,
NPP, landcover,
and landuse (WebTable
3), (b) IGBP land-cover
classes(Friedlet al. 2002;WebTable4), and (c) Olson biomes(Olsonet al.
2001;WebTable5). In (b) and (c), left
columns
showtheanthropogenic
as
biomes
a percentage
ofglobalice-free
barsshow(b) IGBP landcoverand
land,horizontal
as a percentage
(c) Olson biomes
of ice-free
land,andcolumnsincenterillustrate
thepercent
areaofeachanthropogenic
biome
withineachIGBP andOlson class,
systeminteractions
withinand across sortedinorderofdecreasing
total
wildbiomearea, lefttoright.
Colorandorder
of
anthropogenic
biomes?
Before
developinganthropogenic
biome
classes
are thesameas inFigure1.
Given that anthropogenic biomes are
mosaics- mixturesof settlements,
agricul
and other landuses and land
ture,forests
covers- how do we proceed to a general
ecological understandingof human-eco
? The
Ecological
Society
of
America
www.frontersinecolog
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EC EllisandN Ramankutty
biomesof theworld
Anthropogenic
Wildlands
(a)
Forested
Croplands
Rangelands
Dense
Villages
* settlements
Populationdensity
Land use
(b)
Land cover
a
NPP__
Carbon
|
emissions =
Reactive n
~meen
Biodiversity
(c)
104
______
."@'
""""_ _____f"'_""'
Population density
(persons kmin)
100
Land use
(% area)
0
-Land cover =
(% are)
800
NPP
(gmr2 year")
0
0
0
O~~~~
P#0g
M
1,q
-
0~~~~~~~
/
biomes
with
data.(a)Anthropogenic
biomes
modelofanthropogenic
Figure3. Conceptual
compared
structured
bypopulation
density
(logaithmic
red=
landarea),frmning
structure
landcover),
scale)and landuse(percent
patterns
of(b) ecosystem
(NPP,carbon
process
balance;
(percent
topre-existing
+ domestic
white
versus
non-native
relative
reactive
indicated
andbiodiversity
emissions,
nitrogen),
(native
biodiversity;
biodiversity;
net reduction
withinbroadgroupsof anthropogenic
biomes. (c)Mean populationdensity,landuse, landcover,and
space indicates
of biodiversity)
at top.
names
omit
atbottom
NPP observed
within
biomes
anthropogenic
(Figure
1;WebTable
1).BiomelabeLs
groups,
ofbroad
fortestingthem,
we first
a setofhypothesesand a strategy
ofhow theseinter
summarize
our currentunderstanding
ecosystemprocessesat a global
actionspatternterrestrial
scaleusinga simpleequation:
= f(population
land
processes
density,
Ecosystem
geology)
use,biota,climate,terrain,
www.frontiersinecologyorg
Those familiarwith conventional ecosystem-process
modelswill recognizethatours ismerelyan expansionof
these,addinghumanpopulationdensityand landuse as
parameters to explain global patterns of ecosystem
processesand theirchanges.With somemodification,
models
conventional land-use and ecosystem-process
should thereforebe capable of modeling ecological
e The Ecological
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Society of America
EC Ellis andN Ramankutty
Anthropogenic
biomesof theworld
changeswithin and acrossanthropogenic
biomes (Turner gionscapable of servingtheecologicalmonitoringneeds
et al. 1995; DeFries et al. 2004; Foley et al. 2005). We
of regionaland local stakeholders,
a rolecurrently
occu
includepopulationdensityas a separatedriverof ecosys pied by conventionalecoregionmapping and classifica
temprocesses,basedon theprinciplethatincreasing
tionsystems(Olson etal. 2001).
pop
ulation densitiescan drivegreaterintensity
of land use
(Boserup1965, 1981) and can also increasethe direct * Are conventionalbiome systems obsolete?
contribution
ofhumans to local ecosystemprocesses(eg
resourceconsumption,combustion,excretion;Imhoffet We have portrayed
theterrestrial
biosphereas composedof
al. 2004). For example,under the same environmental anthropogenicbiomes,which might also be termed
conditions,ourmodel would predictgreaterfertilizer
and "anthromes"
or "humanbiomes"to distinguish
themfrom
water inputstoagricultural
land inareaswith higherpop
conventionalbiome systems.
This begs thequestion:are
ulation densities,together
with greateremissionsfrom conventionalbiome systems
obsolete?The answeris cer
thecombustionofbiomassand fossilfuel.
tainly"no".Althoughwe have proposeda basicmodel of
ecologicalprocesses
withinand acrossanthropogenic
bio
our
model
remains
mes,
models
conceptual,
while
existing
* Some hypotheses and theirtests
of theterrestrial
biomes,basedon climate,terrain,
andgeol
Based on our conceptualmodel of anthropogenic
biomes, ogy,are fullyoperationaland are usefulforpredictingthe
we proposesomebasichypothesesconcerningtheirutility future
stateof thebiospherein responsetoclimatechange
as a model of the terrestrial
biosphere.First,we hypothe (Melilloetal. 1993;Cox etal. 2000;Crameretal. 2001).
sizethatanthropogenic
in
biomeswill differ
On theotherhand, anthropogenic
substantially
biomesare inmany
terms
ofbasic ecosystemprocesses(egNPP, carbonemis ways a more accuratedescription
of broad ecologicalpat
sions,reactivenitrogen;Figure3b) andbiodiversity
within thecurrentterrestrial
(total, terns
biospherethanarecon
native)whenmeasuredacrosseach biome in thefield,and ventionalbiome systems
thatdescribevegetationpatterns
will be at least as great as those basedon variationsinclimateand geology.It israreto find
that thesedifferences
between the conventionalbiomeswhen observedusing extensiveareas of any of the basic vegetation forms
equivalentmethods at the same spatialscale.Further,
we depictedinconventional
biomemodelsoutsideof theareas
will be drivenbydiffer we have definedaswild biomes.This isbecausemost of the
hypothesizethatthesedifferences
ences inpopulationdensityand landusebetweenthebio world's "natural"ecosystemsare embeddedwithin lands
mes (Figure3a), a trendalreadyevident in thegeneral alteredby landuse and humanpopulations,as isapparent
and when viewingthedistribution
tendencytowardincreasing
croppedarea, irrigation,
of IGBP andOlson biomes
riceproduction
with increasing
populationdensity(Figure withintheanthropogenic
biomes(Figure2 b,c).
3c). Finally,we hypothesizethat the degree towhich
biomesexplain global patternsof ecosys * Ecologists go home!
anthropogenic
temprocessesand biodiversity
will increaseover time,in
tandem
with anticipatedfutureincreasesinhuman influ Anthropogenicbiomespoint to a necessaryturnaround
enceon ecosystems.
inecological scienceand education,especiallyfor
North
The testingof these and other hypothesesawaits Americans.Beginningwith the first
mention of ecology
improved data on human-ecosystem interactions in school, thebiospherehas longbeen depictedas being
obtained by observationsmade within and across the composedof naturalbiomes,perpetuatingan outdated
full range of anthropogenic landscapes.Observations view of theworld as "naturalecosystems
with humans
within anthropogeniclandscapescapable of resolving disturbingthem".Although thismodel has long been
individually
managed land-usefeaturesand built struc challenged by ecologists (Odum 1969), especially in
turesare critical,because this is the scale at which Europe andAsia (Golley 1993), and by those in other
humans interactdirectly
with ecosystemsand isalso the disciplines (Cronon 1983), it remainsthemainstream
optimal scale forprecisemeasurementsof ecosystem view.Anthropogenicbiomes tell a completelydifferent
parametersand theircontrols (Ellis et al. 2006). Given
with natural ecosystems
story,one of "human systems,
the considerable effortinvolved in making detailed embeddedwithin them".This isnominor change in the
measurementsof ecological and human systemsacross story
we tellour childrenand each other.Yet it isneces
heterogeneous anthropogenic landscapes, this will
saryforsustainable
managementof thebiospherein the
requiredevelopment of statisticallyrobust stratified 21st century.
samplingdesigns that can supportregionaland global
Anthropogenicbiomes clearlyshow the inextricable
estimatesbased on relativelysmall landscape samples intermingling
ofhumanandnaturalsystems
almostevery
within and acrossanthropogenicbiomes (egEllis 2004). where on Earth's terrestrial
that
surface,demonstrating
This, in turn,will require improvedglobal data, espe
interactions
between these systemscan no longerbe
cially forhuman populations and land-usepractices. avoided inanysubstantial
way.Moreover,human interac
Fortunately,
developmentof thesedatasetswould also tionswith ecosystems
mediated throughtheatmosphere
pave theway towarda systemof anthropogenicecore
(eg climatechange) are evenmore pervasiveand are dis
()TheEcological
Society
of
America
I
www.frontiersinecology.org
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All use subject to JSTOR Terms and Conditions
biomesof theworld
Anthropogenic
I
EC Ellis andN Ramankutty
proportionatelyaltering the areas least impactedby Ecology,Carnegie Institute
ofWashingtonatStanford,for
humansdirectly(polarand arid lands;IPCC 2007; Figure graciouslyhostinghis sabbatical. P Vitousek and his
1). Sustainableecosystem
managementmust therefore
be group,
G Asner, JFoley,A Wolf, andA de Bremondpro
directed towarddevelopingand maintainingbeneficial videdhelpfulinput.
T Rabenhorstprovided
much-needed
interactionsbetween managed and natural systems, helpwith cartography.
Many thanksto theGlobal Land
because avoidingtheseinteractions
isno longera practi Cover Facility (www.landcover.org)
forprovidingglobal
cal option (DeFries et al. 2004; Foley et al. 2005). Most
land-cover
data and toC Monfredaforricedata.
importantly,
thoughstillat an earlystageofdevelopment,
biomesoffera framework
forincorporating References
anthropogenic
humansdirectlyintoglobalecosystem
models,a capability Bartholome E and Belward AS. 2005. GLC2000:
a new
approach
to global land cover mapping
from Earth observation
data. Int]
that is both urgentlyneeded and as yet unavailable
Remote Sens 26: 1959-77.
(Carpenteretal. 2006).
E. 1965. The
of agricultural
conditions
Boserup
growth: the eco
Ecologistshave longbeen known as thescientists
who
nomics of agrarian change under population
pressure. London,
traveltouninhabitedlands todo their
work.As a result,
UK: Allen
and Unwin.
our understanding
of anthropogenicecosystemsremains Boserup E. 1981. Population and technological change: a study of
IL: University
of Chicago
Press.
with therichliterature
poorwhen compared
on "natural"
long term trends. Chicago,
ecosystems.
has focusedon Carpenter SR, DeFries R, Dietz T, et al 2006. Millennium
Though much recenteffort
Assessment:
research needs. Science 314: 257-58.
integrating
humansintoecologicalresearch(Pickettetal. Cox Ecosystem
et al 2000. Acceleration
of global
PM, Betts RA,
Jones CD,
2001; Rindfusset al. 2004;WebPanel 3 includesmore
in a coupled
due to carbon-cycle
feedbacks
climate
warming
citations) and supportfor this is increasingly
available
model. Nature 408:
184-87.
fromtheUS National Science Foundation(www.nsf.gov; Cramer W, Bondeau A, Woodward FI, et al 2001. Global response
structure and function to
of terrestrial ecosystem
and cli
C02
eg HERO, CNH, HSD programs),ecologistscan and
mate change:
results from six dynamic global vegetation
mod
shoulddo more to "comehome" and workwheremost
els.Global Change Biol 7: 357-73.
humans live.Building ecological science and education Cronon W 1983.
in the land: Indians, colonists,
and the
Changes
on a foundation
of anthropogenic
biomeswill help scien
ecology of New England. New York, NY: Hill and Wang.
tistsand societytakeownershipof a biospherethatwe Daily GO 1999. Developing a scientific basis formanaging Earth's
life support systems. Conserv Ecol 3: 14.
have alreadyaltered irreversibly,
and moves us toward
DeFries RS, Foley JA, and Asner GP. 2004. Land-use
choices:
bal
how best tomanage the anthropogenic
understanding
human
needs
Front Ecol
and
function.
ecosystem
ancing
biospherewe live in.
Environ 2: 249-57.
P, Vancutsem
Defourny
C,
Bicheron
P, et al
2006. GLOBCOVER:
a 300 m global land cover product for 2005 using Envisat
* Conclusions
time series.
MERIS
Human influence
on the terrestrial
biosphereisnow per
vasive.While climate and geologyhave shaped ecosys
temsand evolution in thepast,ourwork contributesto
thegrowingbodyofevidencedemonstrating
thathuman
forcesmay now outweigh these acrossmost of Earth's
land surface today. Indeed,wildlands now constitute
only a small fractionofEarth's land.For the foreseeable
future,the fateof terrestrial
ecosystemsand the species
with human systems:
theysupportwill be intertwined
most of "nature"isnow embeddedwithin anthropogenic
mosaics of landuse and landcover.While not intended
to replaceexistingbiome systems
based on climate,ter
rain,and geology,we hope thatwide availabilityof an
anthropogenicbiome systemwill encourage a richer
view ofhuman-ecosysteminteractions
acrossthe terres
trialbiosphere,and that thiswill, in turn,guide our
investigation, understanding, and management of
ecosystemprocesses and theirchanges at global and
regionalscales.
* Acknowledgements
ECE thanks S Gliessman of the Department of
EnvironmentalStudies at theUniversityofCalifornia,
Santa Cruz, and C Field of theDepartmentofGlobal
www.frontiersinecology.org
VII
mid-term
In: Proceedings
of the ISPRS Commission
Remote
sensing: from pixels
Netherlands.
8-11; Enschede,
symposium,
processes; 2006 May
Ellis EC. 2004. Long-term
to
in the densely popu
ecological
changes
In: DeFries RS, Asner GP, and
lated rural landscapes
of China.
ton RA
and
land-use
(Eds).
Hough
Ecosystems
change.
DC: American
Union.
Geophysical
et al 2006. Measuring
H, Xiao HS,
long-term eco
in densely populated
using current
logical changes
landscapes
and historical
imagery. Remote Sens Environ
high resolution
Washington,
Ellis EC, Wang
100: 457-73.
Feddema
KW, Bonan GB,
JJ,Oleson
in simulating
land-cover
change
1674-78.
et al
2005. The
future climates.
Folke C, Holling CS, and PerringsC.
importance of
Science 310:
1996. Biological diversity,
and the human
scale. Ecol Appl 6: 1018-24.
ecosystems,
consequences
Foley JA, DeFries R, Asner GP, et al 2005. Global
land use. Science 309: 570-74.
of
FriedlMA, Mclver DK, Hodges JCf,etal 2002. Global land cover
from MODIS:
mapping
Sens Environ 83: 287-302.
algorithms
and
early
results.
Remote
JN. 2005. The global nitrogen cycle. In: Schlesinger WH
(Ed). Treatise on geochemistry. Oxford, UK: Pergamon.
in ecology: more
Golley FB. 1993. A history of the ecosystem concept
than the sum of the parts. New Haven, CT: Yale University
Press.
Galloway
an equilibrium
ter
A and Prentice
IC. 1996. BIOME3:
restrial biosphere model
based on ecophysiological
constraints,
resource availability,
and competition
among plant functional
Haxeltine
types.Global Biogeochem
Cy 10: 693-710.
Huston
M.
1993. Biological
262:1676-80.
diversity,
soils, and economics.
Science
? TheEcological
Society
of
America
This content downloaded by the authorized user from 192.168.52.62 on Fri, 30 Nov 2012 15:35:01 PM
All use subject to JSTOR Terms and Conditions
Anthropogenic
biomesof theworld
EC Ellis andN Ramankutty
Imhof?
ML, Bounoua L, RickettsT, et al. 2004. Global patterns in
human
consumption
change
2007:
of net primary production.
Nature
429:870.
IPCC (Intergovernmental
Panel onClimate Change). 2007.Climate
science
the physical
basis. Summary
for policy mak
PickettSTA and Cadenasso ML. 1995. Landscape ecology: spatial
on Climate
Change.
1992. The
SA.
Geneva,
Switzerland:
problem
of pattern
in ecology.
scale
Ecobgy 73:1943-67.
Loveland TR, Reed BC, Brown JF,et al. 2000. Development of a
land-cover
global
characteristics
database
and
IGBP DISCover
from 1 kmAVHRR data. IntJRemoteSens 21:1303-30.
Matson PA, Parton WJ, Power AG, and Swift MJ.
intensification
Agricultural
and
277:504-09.
E.
Matthews
ecosystem
properties.
ence
Science
vegetation
and
land use: new high-reso
inventory of the amount
of wilderness
remaining
in the world.
Ambio 18: 221-27.
Melillo JM,McGuire AD, KicklighterDW, et al. 1993.Global cli
and
change
terrestrial
net
363: 234-40.
RA,
primary
CG,
Brooks
TM,
et al.
the ecology of intensive sustainable
Press.
Stanford University
agriculture.
Stanford,
CA:
Novacek MJ and Cleland EE. 2001. The current biodiversity
event:
scenarios
Acad Sei USA 98: 5466-70.
Odum
EP.
1969. The
164: 262-70.
formitigation
and
BioScience51:933-38.
issues. P
and methodological
challenges
era began
2003. The
greenhouse
anthropogenic
of years ago. Climatic Change 61: 261-93.
Pozzi F, Ataman
E, et al. 2005. Mapping
global urban
M,
and ruralpopulation distributions.Rome, Italy:UN Food and
Agriculture
and Natural
Environment
Organisation.
Resources
Working Paper 24.
Sanderson EW, JaitehM, LevyMA, et al. 2002. The human foot
printand the lastof thewild. BioScience52: 891-904.
Smil V.
1991. General
in the biosphere
energy
energetics:
and civ
ilization,1stedn.New York,NY: John
Wiley & Sons.
BD.
2007.
The
ultimate
1797-98.
Theobald
DM.
2004.
Placing
ecosystem
exurban
Science
engineers.
land-use
315:
in a human
change
modificationframework.FrontEcol Environ2: 139-44.
RE, et al. 2004.
CD, Cameron
A, Green
from climate change. Nature 427:145-48.
Thomas
Extinction
risk
Turner II BL, Skole D, Sanderson S, etal. 1995. Land-use and land
cover
science/research
change:
International Geosphere-Biosphere
recovery. P Nad
no 35.
plan.
Stockholm,
Ptrogramme.
Sweden:
IGBP Report
Vitousek PM, Mooney HA, Lubchenco J,and Melillo JM. 1997.
et al. 2001.
ED,
E, Wikramanayake
of the world: a new map of life on Earth.
Wilkinson BH andMcElroy BJ. 2007. The impactof humans on
continental erosion and sedimentation.Geol SocAm Bull 119:
development.
Human
Dinerstein
DM,
Terrestrial
ecoregions
and resi
organisation
Science
strategy of ecosystem
Olson
the spatial
WF.
Salvatore
2003.
Wilderness and biodiversityconservation.PNad Acad SeiUSA
100:10309-13.
Netting RM. 1993. Smallholders,householders: farmfamiliesand
extinction
2000. Ruralopolises:
of land change:
Ruddiman
Smith
Mittermeier
331-34.
Nad Acad SeiUSA 101:13976-81.
Nature
production.
269:
dential land economy of high-densityrural regions in South
Asia. Urban Stud37:1583-1603.
RindfussRR,Walsh SJ,Turner II BL, etal. 2004. Developing a sci
thousands
1983. Global
Mittermeier
MA.
Qadeer
1997.
lutiondatabases forclimate studies.JCUm ApplMeteorol 22:
474-37.
McCloskey JM and Spalding H. 1989. A reconnaissance level
mate
Syst32: 127-57.
IPCC.
and
systems. Science
ical systems: linking terrestrial ecological,
physical, and socio
areas. Annu Rev Ecol
economic
of metropolitan
components
ers.A reportofWorkingGroup Iof the Intergovernmental
Panel
Levin
in ecological
heterogeneity
PickettSTA, Cadenasso ML, Grove JM,etal. 2001. Urban ecolog
domination
of Earth's
ecosystems.
Science
211:494-99.
140-56.
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