Poverty and Resource Degradation in the Open Agrarian Economy Charles PERRINGS* 1 ...

24 Pages·2001·1.39 MB·English

lanruoJ fo tnempoleveD scimonocE 03 )9891( .42-l dnalloH-htroN
NA LAMITPO HTAP OT ?NOITCNITXE
ytrevoP dna ecruoseR noitadargeD ni eht nepO nairargA ymonocE
selrahC *SGNIRREP
University of Botswana, Gaborone, Botswana
devieceR hcraM ,7891 lanif noisrev deviecer August 1987
sihT repap stcurtsnoc a ledom fo eht nepo nairarga ymonoce ni redro ot erolpxe eht ycnednet fo
ynam hcus seimonoce ot evlove gnola shtap desiretcarahc yb ereves latnemnorivne .noitadarged
It syap laiceps noitnetta ot eht ecnatropmi fo ytidommoc secirp dna eht refsnart metsys ni
gninimreted larutlucirga ytivitca slevel ni yllacigoloce etaciled .smetsys
.1 noitcudortnI
sihT paper spoleved a yroeht of ecruoser noitadarged dna ytrevop ni the
nairarga seimonoce that si tnednepedni of the naisuhtlaM snoitanalpxe
nommoc ni hcum of the ’.erutaretil ehT laciripme melborp at eussi si a yrev
lareneg .eno ehT latnemnorivne noitailopsed of the lehaS dna the nroH of
,acirfA dna the noitutitsed of hcum of the noitalupop of these areas ni the
tsal two decades, are ton .euqinu ehT noitanibmoc of larur ytrevop dna
ecruoser noitadarged has ni fact emoceb a melborp of ylgnisaercni ereves
snoitroporp ni the yllarutlucirga dna yllarotsap desab seimonoce of ,acirfA
aisA dna nitaL .aciremA etipseD sti suomrone eraflew costs dna the ex
omina nrecnoc ti ,setareneg ylevitarapmoc elttil has so far neeb enod ot
erolpxe the sesuac of the melborp at a laciteroeht .level sihT paper offers a
evitcepsrep no the knil neewteb ecruoser noitadarged dna ytrevop ni nepo
*I ma lufetarg ot yerffoeG ,eaarB htenneK noskcaJ dna owt seerefer rof lufpleh stnemmoc no
na reilrae tfard fo siht .repap ehT dradnats remialcsid .seilppa
,eeS‘ rof ylediw gnireffid selpmaxe fo skrow taht ngissa lanit ytilibisnopser rof latnemnorivne
noitadarged ot noitalupop noisnapxe mlohkcE )6791( dna eldduR dna drahsnaM .)1891( ehT
stnemugra fo siht repap era tnetsisnoc htiw decudni-noitalupop segnahc ni ytivitca ,slevel tub
era denrecnoc htiw a retrohs emit emarf naht si yliranidro demussa ni nevird-noitalupop .sledom
yehT dluow osla dnel troppus ot eht smialc fo hcus sa ,setaK ,nosnhoJ dna gniraH ,)7791( taht
eht noitaler neewteb ecruoser noitadarged dna noitalupop noisnapxe si .cinotonom-non It si
ylgnisaercni desingocer taht ereht yam eb rehto srotcaf ni ecruoser noitadarged taht era erom
tnatropmi naht noitalupop ,noisnapxe gniylpmi taht eht etamixorp sesuac fo ecruoser -adarged
noit - gnikcotsrevo dna noitavitlucrevo ~ raeb on citametsys noitaler ot noitalupop esaercni .fc[
ottepeR dna semloH )3891( dna ecraeP .])7891( sihT repap setagitsevni eno tes fo hcus .srotcaf
05.3$/98/8783-4030 0 ,9891 reiveslE ecneicS srehsilbuP .V.B )dnalloH-htroN(
2 C. Perrings, Poverty and agrarian resource degradation
nairarga seimonoce that takes as sti tniop of erutraped the elbitsuahxe
erutan of the cisab ecruoser ni larutlucirga or larotsap seitivitca - .dnal ehT
stluser of the paper gnirps htob morf the ytivitisnes of the tnemnorivne ot
segnahc ni the level of larutlucirga or larotsap seitivitca (a lacisyhp )melborp
dna morf the laropmetretni seciohc of stnega gnitarepo raen the muminim
level of ecnetsisbus na( cimonoce .)melborp
ehT sucof of the paper si the nepo nairarga .ymonoce nepO nairarga
seimonoce reffid morf desolc nairarga seimonoce yliramirp ni the scope for
gnitadommocca ytniatrecnu offered yb yllatnemnorivne evitavresnoc -cudorp
noit .seigetarts nI nepo nairarga seimonoce the secirp of stupni dna stuptuo
are set ni the dlrow ,tekram so the level of laer emocni si denimreted yb
factors that eil edistuo the lortnoc of the stnega of the .ymonoce oT eb ,erus
emocni segnahc htiw the emas citamilc factors that ecneulfni lla nairarga
,ytivitca tub ti si osla elbitpecsus ot ecirp .snoitautculf erehW nairarga
semocni are hcus that there si elttil sulprus ot forego fi the smret of trade
nrut tsniaga hcus ,seimonoce there yam eb few sevitanretla ot gnisaercni
ytivitca slevel sseldrager of the latnemnorivne sksir .devlovni ,deednI the
gnitseretni gniht tuoba nepo nairarga seimonoce of the epyt debircsed here,
si that evitaler ecirp stfihs nac dael ot a evitisop kcabdeef process ni hcihw
gnisaercni slevel of ytivitca dael yltcerid ot gninepeed ytrevop dna ecruoser
.noitadarged
A nrecnoc htiw the yllaitnetop esrevda effects of egnahc ni the cimonoce
dna larutan stnemnorivne of nepo nairarga seimonoce snaem that the paper
addresses snoitseuq desiar ni lareves etiuq tcnitsid areas of the .erutaretil
emoS of these snoitseuq evah neeb gnisuac nrecnoc for a elbaredisnoc doirep
of .emit tsgnomA these, the yllaitnetop esrevda effects of trade neewteb erom
dna ssel depoleved seimonoce that has attracted the tnetsisrep noitnetta of
trade dna tnempoleved stsiroeht ekila - the prospect of gniziresimmi growth
_ nac eb traced kcab ot the work of hcirdeirF tsiL ni 1837. sihT paper offers
snoitanalpxe for hcus yllaitnetop esrevda effects that evah slellarap ni htob
the yticitsale stnemugra of, for ,elpmaxe itawgahB (1958, 1968) dna the
noitasilaiceps ssol stnemugra of, for ,elpmaxe eflacteM dna namdeetS (1979).
erehW the stnemugra of siht paper egrevid morf those offered erehwesle si ni
the detseggus sesuac of the esrevda effects of trade. tI si the seicnegixe of
ytrevop that esiar the prospect of gniziresimmi growth.
esuaceB I ma denrecnoc htiw the ruoivaheb-emit of nepo nairarga
,seimonoce the paper osla sehcuot no a detaler erutaretil no the nur-gnol
scimanyd of nairarga seimonoce detalumits yb s’puresoB naisuhtlaM-itna
sledom (1965, 1981). ytiraD (1980) dna royrP dna reruaM (1981) evah htob
depoleved lamrof sledom of the noitacifisnetni of ecnatsisbus noitcudorp
nihtiw a denifed lacigolonhcet noziroh ni smret of na ylsuonegoxe -reted
denim noitalupop growth ;noitcnuf ytiraD for na nepo ,ymonoce royrP dna
reruaM for a desolc .ymonoce ehT ledom depoleved ni siht paper si ylralimis
C. Perrings, Poverty and agrarian resource degradation 3
denrecnoc htiw the noitacifisnetni of noitcudorp nihtiw a denifed -igolonhcet
lac ,noziroh dna siht si ylralimis nekat ot eb a esnopser ot ylsuonegoxe
denimreted .ilumits tI sselehtreven sreffid morf the ytiraD dna reruaM-royrP
sledom ni niatrec tnatropmi respects. tsoM ,ylsuoivbo ti si ton noitalupop
growth, tub the effects of egnahc ni the dlrow ymonoce no slevel of nairarga
ytrevop that evird the noitacifisnetni of .noitcudorp nI ,noitidda the doirep of
tseretni si ton the seirutnec degasivne yb ,puresoB ,ytiraD or royrP dna
.reruaM tI si the naps of a .noitareneg I ma detseretni ni segnahc gnirrucco
nihtiw the smhtyhr of noitalupop .tnemtsujda nairargA srecudorp at the
muminim level of ecnetsisbus faced htiw suonegoxe ecirp shocks tonnac tiaw
ot dnopser yb larutan cihpargomed .stnemtsujda I ,ma therefore, detseretni ni
a erom tnegru melborp .rehtegotla
yltraP esuaceb of siht ecnereffid ni emit ,evitcepsrep the ledom dessucsid ni
siht paper si osla erom yltcerid decneulfni yb the elbitsuahxe erutan of the
larutan secruoser detiolpxe yb larur .srecudorp ehT cost of desaercni
ytisnetni si ton tsuj gnihsinimid ,snruter ti si yllaitnetop the etelpmoc espalloc
of the cimonoce .metsys ehT ytilibitsuahxe of elbara or larotsap secluoser si
,ton of ,esruoc yltcerid suogolana ot the ytilibitsuahxe of, ,yas a larenim
.tisoped tahW htob evah ni ,nommoc ,hguoht si the ytilibacoverri or
ytilibisreverri of the segnahc .devlovni elbarA or larotsap dnal si ylno
elbawener fi nairarga ytivitca does ton evlovni elbisreverri egnahc that sekam
that dnal sselesu rednu the ygolonhcet .deilppa fI ti does evlovni hcus egnahc
ti si ot lla stnetni dna sesoprup *.elbitsuahxe ehT paper ylgnidrocca
addresses a set of yrev dlo snoitseuq tuoba the erutan of latnemnorivne
seigetarts ni the face of elbitsuahxe secruoser dna lacigolonhcet ,ytilibixelfni
posed htob ni scimonoce dna ygoloporhtna [for a relluf noissucsid of hcihw
see sgnirreP (1987)].
sihT stniop toward eno lanif set of snoitseuq addressed ni siht paper
gninrecnoc the noitcennoc neewteb ytrevop dna ecruoser ,noitadarged dna
that si the set of snoitseuq desiar ni s’neS (1981) lanimes yriuqni otni the
etamixorp sesuac of .enimaf sihT paper si ,detavitom evoba ,lla yb the
ecneirepxe of the nepo nairarga seimonoce that etanimod larur narahaS-bus
.acirfA ehT senimaf that evah detamiced areas of ,apoihtE the lehaS dna
yltnerruc ,euqibmazoM are ylno the tsom suoivbo sngis of daerpsediw
ecruoser noitadarged dna ytrevop ni these .seimonoce ehT eruliaf of trade,
dnalyrD* smetsysoce dnet ot eb ylralucitrap elbarenluv ot gnisaercni ecruoser .esu -ategeV
lanoit revoc sdnet ot eb ,esraps dna slios dnet ot eb roop ni cinagro rettam dna .stneirtun
noitategeveD nac tluser ni egamad morf hcihw ,yrevocer ni eht esnes fo a nruter ot gnitsixe
,snoitidnoc yam reven .rucco eroM ,ylralucitrap retaerg erusopxe fo eht ecafrus fo eht lios stluser
ni rewol retaw ,noitneter gnigaruocne teehs dna yllug ,noisore dna gnicuder eht ytivitcudorp fo
yllacimonoce lufesu stnalp ees[ eldduR dna drahsnaM .])1891( It si osla deugra taht noitcuder
ni ecafrus noitategev yam evah citamilc .stceffe It yam esaercni ecafrus odebla ytivitcelfer( fo
ralos ,)noitaidar dna siht yam esuac eht ria ot esol taeh ,ylevitaidar dna os ot ,dnecsed gnisol
evitaler ytidimuh ni eht ssecorp yenrahC[ )5791( eraH .])7791(
4 C. Perrings, Poverty and agrarian resource degradation
,tcerid and refsnart stnemeltitne retfa sraey fo larur‘ ’tnempoleved seilpmi
that ew era wohemos gnidaersim eht elbaborp stceffe fo eht -laicremmoc
noitasi fo nairarga .seimonoce sihT repap suggests that eht tcapmi fo yna
egnahc ni eht cimonoce tnemnorivne fo an nepo nairarga ymonoce lliw yrav
htiw htob eht level fo ytivitca eht( ytisnetni fo ecruoser esu nihtiw eht
gnitsixe lacigolonhcet ,)noziroh and htiw eht ytivitisnes fo eht larutan
tnemnorivne ot egnahc ni that .level esuaceB esrevrep stceffe era ton ylno
elbissop tub elbativeni ni niatrec ,sesac ti yam eb lufesu ot evah a esnes fo
eht noitanibmoc fo secnatsmucric that ekam this 3.os
2. gnisiretcarahC eht nepo nairarga ymonoce
ehT aitnereffid acificeps fo nairarga seimonoce erehwyreve era a yvaeh
ecnailer no larutlucirga ro larotsap ,seitivitca and eht esu fo a yllacipyt
yratnemidur ygolonhcet that is tnatsnoc revo dednetxe .sdoirep ieF and
Ranis evah debircsed hcus seimonoce as yllaitnesse‘ stagnant htiw erutan and
noitalupop gniyv rof ycamerpus revo gnol sdoirep fo dedrocer .yrotsih
revoeroM . . . eht sisongorp rof eht erutuf is ylekil ot eb erom“ fo eht ’”emas
,8791( p. .)2 ztluhcS )4691( saw this as a ralucitrap‘ epyt fo cimonoce
’muirbiliuqe ni hcihw eht etats fo eht arts noitcudorp( )snoitcnuf and
secnereferp ytilitu( )snoitcnuf erew htob ,tnatsnoc ni hcihw eht lanigram
lacisyhp tcudorp fo all secruoser deyolpme was ,orez and ten savings erew
esolc ot .orez ehT last owt seitreporp erew ;deknil eht evitnecni ot evas gnieb
kaew esuaceb fo eht wol lanigram lacisyhp tcudorp fo .’latipac‘ ehT ytivegnol
fo eht ygolonhcet deyolpme ni nairarga seimonoce was nekat yb ztluhcS ot
ylpmi that eht ralucitrap epyt fo cimonoce muirbiliuqe eh sebircsed was, ni
,tcaf .elbats
sihT seerga htiw eht erom lamrof ledom fo eht desolc nairarga ymonoce
detcurtsnoc yb nietsnebieL )7591( hcihw detareneg what eht rohtua dellac a
elbats-isauq ,muirbiliuqe ro a elbats muirbiliuqe lanoitidnoc no eht ymonoce
denrecnoc gnieb detalusni morf lanretxe .secneulfni retaL stpmetta ot ledom
eht cimanyd seitreporp fo nairarga seimonoce evah neeb less ni .drocca
royrP and ,reruaM rof ,elpmaxe evresbo that fo ytxis hcus seimonoce
dehcraeser yb eno fo eht ,srohtua all demees‘ rehtie ot eb at, ro gnivom
,sdrawot a citats ’muirbiliuqe ,2891( p. ,)623 making ti ylthgils cinori that eht
desolc nairarga ymonoce sledom depoleved yb eht srohtua degrevnoc ot
positive htworg paths ni tsom ,sesac neve hguoht yeht desingocer that rednu
rieht nwo assumptions ereht had ot eb nur-gnol‘ ’stimil ot eht htworg fo eht
ymonoce ,2891( p. .)643 yB ,tsartnoc eht nepo ymonoce ledom detcurtsnoc
ehT3 repap seod ,ton ,erofereht sserdda eht knil neewteb ecruoser noitadarged dna -onhcet
lacigol .egnahc It si htrow ,gniton ,revewoh taht ynam fo eht tsom ylnommoc detic secnatsni fo
lacigolonhcet egnahc - eht noitcudortni fo peed ,sllew rof elpmaxe - yam eb deterpretni sa eht
noitacifisnetni fo ytivitca nihtiw a nevig .ygolonhcet
C. Perrings, Poverty dna agrarian resource degradation 5
yb ytiraD ,)0891( setareneg a ylhgih elbatsnu muirbiliuqe - a efink egde -
ecnegrevid morf hcihw ylirassecen sdael rehtie ot eht espalloc ro ot eht
sustained htworg fo eht .metsys erehT is at tsael a laicifrepus ytiralimis
neewteb eht sehcaorppa fo ytiraD and ,nietsnebieL ni that eht gninepo fo eht
drawkcab‘ seimonoce debircsed yb nietsnebieL was deugra ot etaerc at tsael
eht ytilibissop fo ylralimis sustained muirbiliuqesid .htworg ehT owt ,did
,revewoh evah tnereffid lacirotsih secnatsmucric ni dnim nehw discussing eht
gninepo fo lanoitidart nairarga seimonoce - ylralucitrap ni .acirfA roF
ytiraD ti was eht edart ni sevals ton sdoog that was .tnatropmi
ehT lacigoloporhtna ecnedive suggests that eht tnerappa ytilibats fo desolc
nairarga seimonoce was eht tcudorp fo a egnar fo lanoitutitsni lortnoc
smsinahcem dengised ot eetnaraug eht ymonoce ni eht ecaf fo an niatrecnu
tnemnorivne ees[ stivoksreH ,)0491( Nash )7691( and Sahlins .])4791( Using
hcus lacigoloporhtna ecnedive I evah deugra erehwesle sgnirreP[ 13891( that
eht tnanimod erutaef fo nairarga seimonoce is eht ecnetsixe fo snoitutitsni ot
timil eht level fo yticapac noitasilitu ot yllatnemnorivne sustainable .slevel
erehT is on nosaer ot ,eveileb ,revewoh that hcus seimonoce erew -imonoce
yllac .elbats ecniS laer emocni and savings era htob ylevitisop detalerroc htiw
yllarutlucirga elbaruovaf latnemnorivne snoitidnoc llafniar( ,).cte eht -ugernu
detal desolc nairarga ymonoce dluohs eb enorp ot yltcaxe eht emas
yllacitamilc denimreted gnizargrevo and noitavitlucrevo that has neeb deugra
as a esuac fo ecruoser noitadarged ni eht .lehaS ehT ecnetsixe fo snoitutitsni
ot tcirtser tnemtsevni ot sustainable slevel sraeppa ot evah neeb a laicurc
rotcaf ni eht ytivegnol fo yllacimonoce elbatsnu ro ylno yllacol elbats desolc
nairarga .seimonoce
ehT gninepo fo eht nairarga seimonoce fo acirfA htob hguorht eht evals
edart and rieht noitaroprocni ni dlrow tcudorp stekram has degnahc rieht
scitsiretcarahc ni yrev tnatropmi .syaw ecniS niatrec tupni and tuptuo secirp
era tes ni dlrow stekram eht knil neewteb laer ,emocni savings, and lacol
latnemnorivne snoitidnoc has neeb yltrap .dereves eroM ,ylralucitrap eht elor
fo lanoitidart snoitutitsni ni gnitaluger yticapac noitasilitu has neeb substan-
yllait ,denekaew htiw snoitacilpmi htob rof eht evitnecni stceffe fo lanoitidart
lanummoc ro nommoc ,ytreporp and rof eht yaw that ytniatrecnu is
.detadommocca erehT era won owt secruos fo ytniatrecnu - eht tnemnorivne
and eht dlrow tekram - and eht ruoivaheb fo nairarga srecudorp is yrev
hcum a noitcnuf fo eht sdohtem nesohc ot esiminim risk ni htob .saera
nI all nepo nairarga ,seimonoce recudorp seigetarts rof gnisiminim risk
egnih no snoisiced ni owt :saera eht lanoitidart eciohc as ot eht lamitpo level
fo ;ytivitca and a wen eciohc neewteb noitcudorp rof rehtie tcerid -pmusnoc
noit ro rof eht tekram enotsgniviL[ .])1891( ehT tnatropmi tniop ereh is that
rehtien eht tekram risk ron eht tcerid noitpmusnoc risk fo tsevrah eruliaf era
elbarusni tpecxe hguorht eht snoisiced edam yb nairarga srecudorp ni eseht
owt .saera ,ylgnidroccA ecnis srecudorp raen eht muminim ecnetsisbus level
6 C. Perrings, Poverty and agrarian resource degradation
ylpmis tonnac take a ssol woleb ,ecnetsisbus yeht dnet ot adopt what notpiL
(1968) has dellac lavivrus‘ :’smhtirogla yllatnemnorivne evitavresnoc secitcarp
desiretcarahc yb the noitceles of wol eulav tub tsubor crops or kcotsevil
elbatius for htob tekram noitcudorp dna tcerid .noitpmusnoc yehT dnet ot
diova hgih )tekram( eulav tub yllatnemnorivne elbitpecsus crops or kcotsevil
that are ton yltcerid elbamusnoc fi deen eb [cf. osla yemaY (1964)]. ehT ksir
gnisiminim seigetarts of srecudorp ni the nepo nairarga seimonoce -drocca
ylgni saib noitcudorp dna noitpmusnoc snoisiced ni ruovaf of deirt secitcarp
dna lanoitidart ,stcudorp dna tsniaga lacigolonhcet .noitavonni gninepO the
nairarga ymonoce does ton therefore ylirassecen dael ot the noitpoda of
noitavonni ,secitcarp ylralucitrap where lacigolonhcet egnahc si flesti a
ecruos of ksir [see ztluhcS (1964)]. ehT costs of hcus lacigolonhcet -resnoc
,msitav ni smret of the noitasilaiceps sessol of trade, are ylticilpmi accepted
as part of the muimerp ot eb diap for the ksir of gnitapicitrap ni the dlrow
.tekram
A yrev ralimis set of snoitaredisncc mrofni the sgnivas ruoivaheb of
nairarga .srecudorp sgnivaS ni the nepo nairarga ymonoce yam yllanoiton eb
edam ni the mrof of rehtie laicnanif or laer ;stessa ,yenom knab stisoped dna
the ,ekil or niarg dna .kcotsevil nI fact the ytilibissop for gnivas ni laicnanif
assets sdnet ot eb detimil yb the ytilibaliava of laicnanif ,snoitutitsni hguoht
the ecnesba of hcus snoitutitsni yam osla eb a ecneuqesnoc of the fact that
the ytefas detneiro lavivrus smhtirogla deyolpme ruovaf gnivas ni laer assets.
gnivaS ni laer assets sedivorp htob a snaem of tcerid noitpmusnoc ni the case
of thguord ecnarusni( tsniaga tcerid tnemeltitne )eruliaf dna a degree of
noitcetorp tsniaga the ytilitalov of tcudorp secirp ecnarusni( tsniaga trade
tnemeltitne 4.)eruliaf nA tnatropmi noitacilpmi of siht si that sgnivas dna
tnemtsevni snoisiced dnet ot eb nekat yb the emas .stnega laeR sgnivas
desilaer yb dlohesuoh‘ ’noitnetsba ylpmi tcerid tnemtsevni yb the dlohesuoh
head htriF[ (1964)]. latipaC ni the nepo nairarga ymonoce si ton yleerf
.elibom
ekiL lla other cimanyd ,seimonoce the nepo nairarga ymonoce si nevird yb
,sgnivas tub ti si sgnivas tuo of the yranoitercsid emocni of elpoep gnivil
esolc ot the ytrevop enil dna ytrevop snrut tuo ot evah yllaicurc tnatropmi
effects. ,ytrevoP ni siht ,txetnoc si ’evitcejbus‘ ni the esnes that ti si denifed yb
the ’stnega nwo tnemssessa of deen [see ikswonwerD (1977)] hguoht( few
dluow yned that the evitcejbus ytrevop of seegufer ni euqibmazoM or the
naduS sevlovni laer .)noitavirped roF tneserp sesoprup ytrevop yam eb dias
ot tsixe reverehw there si gnivassid ot niatniam .noitpmusnoc ehT‘ -adarged
noit of larutan secruoser - whether the noitategeved of ,sdnaldoow the
noitsuahxe of lios ,stneirtun the tnemhsinelped of ,srefiuqca or the noitavrats
yltneceR4 eht sgnivas fo nairarga srecudorp ni smret fo laer stessa sah neeb deterpretni yb
noillavaR sa evitaluceps gnidraoh ,)7891( tub siht sessim eht ecnarusni elor fo laer sgnivas ni
seimonoce erehw tsom srecudorp era esolc ot eht muminim level fo .ecnetsisbus
C. Perrings, Poverty and agrarian resource degradation I
of kcotsevil - stneserper gnivassid of the tsom tnatropmi assets of the
nairarga ,ymonoce dna there are few retteb srotacidni of the tnetxe of larur
.ytrevop
A lanif citsiretcarahc of nairarga seimonoce worth gniton setaler ot the
artni dlohesuoh noitubirtsid of emocni dna noisivid of .ruobal elihW there
ylniatrec stsixe a noisivid of robal desab no htob age dna ,redneg enon si
tpmexe morf ruobal evas the yrev dlo dna the yrev .gnuoy llA srebmem are
therefore demussa ot gnoleb ot the dlohesuoh workforce. roF ecneinevnoc ti
si demussa that lla evah na lauqe mialc ot dlohesuoh .emocni esehT suoirav
scitsiretcarahc are won desirammus ni the lamrof ledom of the nepo nairarga
.ymonoce
ehT emocni detareneg yb larutlucirga or larotsap ytivitca rednu the state
of erutan gniliaverp ni the kth doirep of the yrotsih of the ymonoce si
denifed yb
(1)
Y(k)=Q(k)CbCQ(k)lP(kI+)- aP(k
where Y(k) setoned ;emocni Q(k) setoned the level of ,ytivitca or the level of
ytisnetni of ecruoser ;esu b[Q(k)] setoned a tinu ytivitca level tuptuo
tneictffeoc as a noitcnuf Q(k); a setoned a tnatsnoc tinu ytivitca level tupni
;tneiciffeoc dna P(k+ ,)l P(k) etoned ’dlrow‘ secirp of nairarga stuptuo dna
stupni .ylevitcepser llA except the tupni ,tneiciffeoc a, are elbairav revo .emit
emiT si treated yletercsid ecnis siht smees ot eb the tsom larutan yaw of
gnilaed htiw noitcudorp that si lanosaes ni .erutan emocnI si detubirtsid
yllauqe ot lla srebmem of the nairarga ruobal force, hcihw si demussa ot eb
of tnatsnoc ezis ni the doirep of tseretni (the naps of a .)noitareneg ecneH
Y(k) = NW(k), (2)
where N setoned the nairarga ruobal force, dna w(k) setoned the emocni of
each rebmem of the ruobal force. ecniS the ytisnetni of ruobal seirav htiw the
level of ytivitca we evah osla
)k(Y = QWW44 (3)
where n(k) setoned the ytisnetni of .ruobal ehT rehgih the level of ytivitca the
greater the ytisnetni of nairarga .ruobal
noitcudorP ni the nairarga ymonoce yam suht eb desiretcarahc yb a
noitcnuf gnitaler ,tuptuo Q(k)b[Q(k)], ot ,ruobal Q(k)n(k), dna lairetam
,stupni Q(k)a. dnaL si demussa ot eb ni dexif ylppus dna ylno sretne the
noitcudorp noitcnuf ,yticilpmi aiv sti effect no the ytivitcudorp of dexif
seititnauq of ruobal dna lairetam stupni desu at gnireffid slevel of .ytisnetni
sihT selbane su ot erutpac the elor of a factor of noitcudorp that si ton
8 C. ,sgnirreP ytrevoP dna nairarga ecruoser noitadarged
I
b
.giF 1
traded ni the yranidro .esnes ehT ,ygolonhcet ni other words, stcelfer the fact
that ruobal dna lairetam stupni are denibmoc htiw a yllaitnetop elbitsuahxe
,ecruoser .dnal
ehT effects of erusserp no dnal si derutpac ni the eulav of the tuptuo
tneiciffeoc rednu tnereffid ytivitca .slevel sihT si nekat ot tibihxe tsrif
gnisaercni dna neht gnihsinimid .snruter gnittimO the emit xedni for the
,tnemom the tsrif sevitavired of )Q(b are evitisop for lla Q pu ot emos eulav
Qbmax denifed( )retal dna are evitagen ;retfaereht the dnoces sevitavired are
evitisop for lla Q pu ot emos eulav <Q ,xambQ dna are evitagen thereafter for
tsom Q of .tserertni tahT :si
0>)Q(’b for lla ,XambQsQ
0~ for lla ;xambQ>Q
for
b"(Q-=z)0 lla Q <<tJ ,xambQ
0~ for .Q>Qtsom
ecitoN that siht sedulcerp the cilobarap noitcnuf yllamron demussa ni
elbitsuahxe ecruoser ,smelborp ecnis ti stsisni that there are gnisaercni
snruter ot elacs at wol slevel of ytisnetni of ecruoser .esu nI ,lareneg
therefore, we dluow expect the graph of the noitcnuf ot eb of the mrof nwohs
ni .gif 1. roF ,ssenetercnoc ,revewoh I evah demussa the noitcnuf ot eb of a
yrev ,cificeps ,lacirtemmys :mrof
(4)
where b,,, setoned the mumixam tinu ytivitca level tuptuo ;tneiciffeoc xambQ
C. Perrings, Pooerty and agrarian resource degradation
b = Q(2/l-Lpxexamb - ]2dmQ
b
.giF 2
setoned the ytivitca level at hcihw b sniatta a .mumixam sihT noitcnuf has lla
the deriuqer seitreporp debircsed .evoba stI graph si of the mrof nwohs ni
.gif 2.
,hguohtlA as we evah ,nees segnahc ni the level of ytisnetni are ton nevird
yb noitalupop ni the emit elacs of tseretni ni siht paper, yeht do evah ralimis
snoitacilpmi for the emit path of the .metsys ecniS dnal si regarded as na
elbitsuahxe ecruoser there are yrev raelc dna denifed-llew stimil ot the
ytisnetni at hcihw ti nac eb detiolpxe rednu a nevig ,ygolonhcet dna a nevig
state of .erutan oT tcelfer the effects of egnahc ni the state of erutan of the
eulav of b(Q) eq. (4) lliw eb nettirw ni the emit dexedni :mrof
W = h,,,,W)e xp C- VXQ(4 - Q~,,,(4121.
oT erolpxe the scimanyd of the nepo nairarga ymonoce we deen ot yficeps
the sgnivas ruoivaheb of nairarga .srecudorp latoT sgnivas are denifed yb
S(k) )k$.= )k(Y , (6)
where s(k) setoned the nairarga srecudorp ytisneporp ot evas ni doirep k. tI
yam eb ,evitisop evitagen or zero. sA detacidni ,reilrae sgnivas are -reted
denim yb the noitaler neewteb lautca emocni dna the deviecrep muminim
ecnetsisbus sdeen of nairarga .srecudorp sihT yam eb thguoht of as the
ytrevop ,tniop dna si detoned .F ehT noitaler neewteb sgnivas dna ytrevop si
neht debircsed yb
10 C. Perrings, Poverty and agrarian resource degradation
where scri a evitisop tnatsnoc gnitacidni the dexif noitroporp of yranoitercsid
emocni .devas ehT lareneg ytisneporp ot evas ylgnidrocca seirav htiw the
tnuoma of emocni denrae evitaler ot the )evitcejbus( ytrevop .tniop nI lla
,sdoirep
-_ l[IW .)k(w])k(s- (8)
ecniS tnemtsevni ni doirep k+ 1 si ylpmis
I(k + 1) = Q(k+ k(Pa)l + ,)l (9)
the sgnivas tnemtsevni ytitnedi takes the mrof
Q(K+ l)aP(k+ l)=s(k)Q(k)n(k)w(k). (10)
,suhT fi dlrow secirp are ,elbats the metsys si nevird yb the noitcaretni of two
:selbairav the ytisneporp ot ,evas dna the ytivitcudorp of yratnemelpmoc
factors at the gniliaverp level of ytisnetni of ecruoser .esu esehT two selbairav
are ton .tnednepedni More ,ylralucitrap the ytisneporp ot evas lliw esir )llaf(
htiw na esaercni ni the level of ytisnetni of ecruoser esu for lla ytisnetni slevel
ssel naht (greater )naht the mumixam emocni .level oT see siht eciton that
the mumixam emocni level of larutlucirga ,ytivitca dnuof yb gnittes the
evitavired of Y(k) htiw respect ot Q(k) lauqe ot zero, si nevig yb
Q,max(=k)C~(khUW’(W + Qtu,,axM )11(
where V(k) =Q(k)b(k)P(k+ 1) setoned the eulav of nairarga .tuptuo gnikaT
the evitavired of s(k) htiw respect ot Q(k) ni (7),
dsO=n-~[n(k)w(k)-[Q(k)-Qb,,,(k)]V(k)], 41(
dQ(4 y(k)
ti swollof yletaidemmi morf (11) that siht lliw eb evitagen for lla Q(k)>
Q,,,,(k), dna evitisop for lla Q(k) <Q ymax(k). sA egareva emocni segnahc htiw
the level of ytivitca so too does yranoitercsid ,emocni dna htiw ti the
ytisneporp ot .evas
sihT setelpmoc the noitpircsed of the lamrof erutcurts of the nepo nairarga
ymonoce .ledom sA htiw yna ledom depoleved at a hgih level of noitcartsba
morf the ytilaer ti si dednetni ot ,nialpxe ti sessim hcum of the ssenhcir of the
laicos dna lacitilop cirbaf nihtiw hcihw nairarga srecudorp ekam rieht
.snoisiced tI does, ,revewoh erutpac what mees ot eb the scitsiretcarahc of
nairarga seimonoce tsom tnatropmi ot na gnidnatsrednu of rieht ruoivaheb