Empirical Analysis of Pastoral Migration Decisions: Gabra Herders in Northern Kenya

Transcription

1 Emprcal Analyss of Pastoral Mgraton Decsons: Gabra Herders n Northern Kenya John McPeak Department of Agrcultural and Appled Economcs Unversty of Wsconsn-Madson Presented at the 1998 Amercan Agrcultural Economcs Assocaton Annual Meetng Salt Lake Cty, Utah Ths research was asssted by an Internatonal Predssertaton Fellowshp from the Socal Scence Research Councl and the Amercan Councl of Learned Socetes wth funds provded by The Ford Foundaton. Copyrght 1998 by John McPeak. All rghts reserved. Readers may make verbatm copes of ths document for non-commercal purposes by any means, provded that ths copyrght notce appears on all such copes.

2 Emprcal Analyss of Pastoral Mgraton Decsons: Gabra Herders n Northern Kenya John McPeak Abstract: Recent research n range ecology suggests the process of resource degradaton n Afrcan ard and semard rangelands may be less relant on how many anmals are placed on the rangeland than on where these anmals are placed. Analyss of pastoralst land use decsons ndcates there s evdence rangeland condton nfluences lvestock placement, but that food and ncome producton strateges, herd characterstcs and household characterstcs also play crtcal roles.

3 Sub-Saharan Afrca s experencng an agraran crss. The extent of ths crss s ndcated by the fact that on a contnent where over seventy percent of the labor force s nvolved n agrculture, the past twenty years have wtnessed declnng per-capta agrcultural producton (Herbst 1993). Addressng ths crss n the area of lvestock producton wll play a crtcal role n haltng ths declne, as lvestock producton accounts for twenty-fve to thrty-fve percent of agrcultural producton n Afrca (USDA 1990). The prevalng vew n economcs descrbes the crss n lvestock producton as a manfestaton of the tragedy of the commons descrbed by Hardn (1968). Ths perspectve mples Afrcan lvestock producers accumulate more anmals than s economcally and ecologcally effcent. The economc sub-optmalty arses from the cost mposed on all herders when the aggregate herd s bult up past the level of rangeland carryng capacty, causng hgh rates of stock mortalty. The ecologcal sub-optmalty arses from the long-term process of rangeland degradaton caused by excessve stockng levels. Ths analyss of the stuaton has led to proposals that lmt stockng levels. For example, Doran, Low et al. (1979) state Afrca s now perhaps the classc example of a contnent sufferng from sol eroson caused by overgrazng. They suggest t wll be necessary ether to mplement measures that wll nduce stockowners to sell more cattle or, alternatvely, to enforce control of cattle numbers. The emprcal record of polces based on these proposals s dsappontng. Scoones (1995) wrtes the last 30 years have seen the unremttng falure of lvestock development projects across Afrca. Mllons of dollars have been spent wth few obvous returns and not a lttle damage. Most commentators agree that the experence has been a dsaster Recent ecologcal research may provde nsght nto some of the reasons for ths falure. One mportant result s that rangeland productvty n ard and sem-ard lands, as well as boom 1

4 and bust cycles n lvestock populatons, may be more constructvely vewed as consequences of exogenously determned ranfall levels rather than endogenously determned stockng rates (Ells and Swft 1988; Westoby, Walker et al. 1989; Behnke and Scoones 1993). Ths mples that an assessment of economc sub-optmalty based on herders exceedng the rangeland s fxed carryng capacty s of lmted use f the rangeland s carryng capacty s fluctuatng over tme. A second result of note s the nablty of studes of rangeland condton to clearly dentfy wdespread rangeland degradaton as an emprcal phenomenon (McCabe and Ells 1987; Hellden 1991; Abel 1993; Bot 1993). Taken together, these results ndcate frequent drought events may prevent lvestock populatons from attanng levels where wdespread degradaton occurs. If ths s the case, polces that lmt stockng levels may brng about lttle sgnfcant change n rangeland condton whle mposng great costs on herders welfare. Whle the assumpton of wdespread degradaton may be questonable, there s a growng amount of evdence assocatng localzed degradaton wth key resources such as towns and water ponts (Schwartz, Shaaban et al. 1991; Dodd 1994). Understandng ths phenomenon requres that we shft the focus of analyss from how many anmals are placed on the commonly held rangeland to a focus on what determnes where anmals are placed wthn ths rangeland. Ths study approaches ths ssue by emprcally nvestgatng varables that nfluence pastoralsts land use decsons. DESCRIPTION OF THE STUDY AREA The Gabra are nomadc pastoralsts who lve n Marsabt Dstrct n northern Kenya. The Gabra lvestock producton system utlzes a mxture of camels, cattle, sheep, and goats. Households consume mlk, meat and blood from anmals. Lvestock and lvestock products such as mlk are sold to generate ncome. 2

5 The Gabra share rghts to rangelands that are best descrbed as ard or sem-ard, as the vast majorty of ths area has medan annual ranfall of less than 300 mm. The tradtonal Gabra mgraton strategy s to graze herds on rangelands near wells durng dry perods, usng the wells to water ther anmals. These rangelands are vacated durng rany perods, as temporary catchments provde water for anmals n areas away from wells. Ths strategy spreads grazng pressure on rangelands by perodcally vacatng zones near permanent water, gvng these pastures a chance to regenerate durng the rany season. Herders report ths pattern has been ncreasngly dsrupted over the past 30 years by the growth of permanent settlements around wells. Ths dsrupton appears to have an ecologcal consequence. A recent evaluaton of Marsabt Dstrct rangelands found 98% of the area exhbtng no evdence that rangeland productvty has been reduced by lvestock use. The 2% exhbtng sgns of degradaton are assocated wth the areas surroundng towns (Schwartz, Shaaban et al. 1991). In attemptng to understand ths pattern, ths study has two goals. The frst s to dentfy the extent to whch the tradtonal mgraton strategy has been dsrupted. The second s to dentfy ncentves assocated wth ths dsrupton. A MODEL OF LAND USE DECISIONS To explore these ssues, a utlty maxmzaton model of herder decson makng s developed, where utlty s a functon of consumpton. The model s desgned so that a herder s land use decson s condtoned on rangeland condton, herd characterstcs and household characterstcs. The crtcal component of ths model s dentfyng ways n whch land use decsons nfluence consumpton levels, and hence, herder s well beng. Concernng rangeland condton, assume that herder can choose to graze hs anmals n ether of two rangeland zones. Zone one s defned as the area n whch a round trp walk to town 3

6 can be completed n a day, and zone two s the area where ths trp takes more than a day. 1 Each herder selects the fracton of hs herd s effectve grazng tme to be allocated to zone one, whch s the land use choce varable tz1. Ths mplctly defnes the percent of grazng tme spent by herder s herd n zone two as (1- tz1 ). Before makng hs choce, the herder observes a measure of the quantty and qualty of pasture avalable n each zone. These observatons are defned by the varables pa z1 and pa z2. The state of the rangeland nfluences consumpton through mlk producton mp, as t s assumed mlk producton s an ncreasng functon of pasture avalablty. Mlk producton s also nfluenced by the state of the herd. It s assumed mlk producton ncreases as herd sze ncreases, where herd sze s descrbed by the total anmal unts n the herd, k. 2 Observed herd characterstcs represented by the vector ν also nfluence mlk producton. Unobserved varables that nfluence mlk producton are represented by the dsturbance term ω. Total mlk producton s the sum of mlk produced n the two zones. z1 z1 z2 z2 (1) mp = mp ( k, tz1, pa, υ, ω ) + mp ( k,( 1 tz1 ), pa, υ, ω ) Mlk can be consumed drectly by the household, or sold at prce p to purchase other consumpton goods. In the study area, women make decsons over mlk allocaton, whle men make grazng tme allocaton decsons. Assume the husband n household s famlar enough wth the hstory of hs wfe s mlk allocaton that the fracton of the mlk sold by hs wfe can be represented by a functon s( tz1, mp, k, λ, ψ ), where λ captures household characterstcs and 1 More precsely, a radus the length of a fve hour walk, a dstance of 15 to 20 klometers, defnes zone one. The area outsde the crcle descrbed by ths radus s zone two. 2 One anmal unt s equal to 0.7 camels, 1 head of cattle, or 10 sheep or goats. 4

7 ψ s a dsturbance term. 3 It s assumed that ths fracton s an ncreasng functon of tme spent n zone one, as proxmty to town nfluences mlk marketng due to transport and spolage consderatons. It s also assumed that ths fracton s an ncreasng functon of mlk producton, as sales occur durng tme perods when producton s greater than household needs. Herd sze s ncluded as a wealth proxy, as mlk marketng may be a producton strategy adopted by certan wealth classes n socety. Another mportant factor n determnng consumpton levels n the study area s food ad. As food ad s dstrbuted from towns, t s assumed the quantty of food ad receved by herder s a functon of proxmty to town. If a herder s far away from town, he may fnd that he expends more energy obtanng the food n town than s ganed by consumng t. Food ad s also nfluenced by the amount of food delvered to town, denoted fad. These factors lead to specfcaton of a food ad functon fa( tz1, fad). All other consumpton goods that are not a functon of tme spent n zone one are represented by the varable z. 4 Assumng a weghtng scheme represented by the vector γ can be used to make ndvdual components of the consumpton functon commensurable, the followng equaton results. 5 m (2) c = γ p s( tz1 ) mp + γ ( 1 s( tz1 )) mp + γ fa( tz1, fad) + γ z Herders gan utlty from consumpton, where the utlty functon s common to all herders, holdng household characterstcs λ constant. We can wrte the problem facng herder as : 3 Dervaton of the s(.) functon from the underlyng decson process for the wfe s left as a separate ssue. 4 Note that ths specfcaton of a composte good z separates slaughter and sales decsons from the land use decson. Although there may be some correlaton amongst these decsons, t s arguably slght. Further modelng efforts wll explore these connectons. For ths paper s focus on land use decsons n a statc settng, sales and slaughters are judged to add unecessary dynamc complcaton to the model. 5 Such a weghtng scheme could be the relatve calore value of each tem. For example, a lter of mlk exchanges for a klogram of maze, but a klogram of maze has 5 tmes the calore value of a lter of mlk. 5

8 ( γ p s( tz1 ) mp + γ ( 1 s( tz1 )) mp + ) (3) Max U γ fa( tz1, fad ) + γ z ; λ tz1, z m z1 z1 z2 z2 where mp = mp ( k, tz1, pa, υ, ω ) + mp ( k,( 1 tz1 ), pa, υ, ω ) Takng the frst order condton wth respect to tz1 leads to the followng result. t (4) s m mp m mp ( γ 1 p γ 2 ) + ( γ 1 p s( tz1 ) + γ 2 ( 1 s( tz1 ))) U tz tz 1 1 c fa tz fad = 0 ( 1, ) + γ 3 tz1 where mp tz1 z1 z1 z2 z2 mp ( k, tz1, pa, υ, ω) mp ( k,( 1 tz1 ), pa, υ, ω) = tz1 tz1 Consder the followng partally solved verson of equaton (4). * * z1 z2 * z1 z2 m (5) tz1 = f( s( tz1 ), mp( k, pa, pa, tz1, υ, ω), k, pa, pa, p, fad, υ, ω, γ; λ ) From ths representaton, we can dentfy varables that nfluence the land use decson. The herd sze k, the pasture avalablty n the two zones pa z1 and pa z2, the herd specfc characterstcs υ and the household characterstcs λ are all ndcated by ths model as potentally nfluencng grazng allocaton decsons. The functons concernng mlk producton and the share of mlk sold also appear mportant n ths decson. As these functons are determned by the optmal decson, they are not causes but results of the land use decson. As the nature of these functons s mportant to understand land use decsons, they are also estmated. Rearrangng equaton (5) leads to (6), whch descrbes the relatonshps emprcally nvestgated n the followng secton. (6) * z1 z2 m tz1 = g( k, pa, pa, p, fad, υ, ω, ψ, γ; λ ) * * * s = h( tz1, k, mp, υ, ψ) * z1 z2 * mp = mp( k, pa, pa, tz1, υ, ω) 6

9 EMPIRICAL ANALYSIS OF LAND USE INCENTIVES To date, ntervews have been conducted wth 23 households to recover nformaton for the perod long rans 1993 to long rans Each year conssts of four dstnct tme perods: long rans, dry season followng long rans, short rans, dry season followng short rans. Ths provdes a panel data set (n,t), n = 1,,23, t = 1,,17 7. The data set does not contan precse observatons on whch anmals were located n each zone for each tme perod, but does contan relable nformaton on the dvson of household labor for each perod. As there s a drect connecton between the labor force allocated to each zone and grazng tme n each zone, the labor allocaton decson s used as a proxy for the land use decson n the estmaton procedure. Famly labor s allocated to a base camp or a satellte camp n each tme perod. Base camps can be n ether zone one or zone two, satellte camps are always n zone two. If we observe all labor tme allocated to zone one, whch occurs when the base camp s n zone one and there s no satellte camp, then tz1 t = 1. If we observe all labor tme allocated to zone two, whch occurs when the base camp (and possbly also a satellte camp) s located n zone two, ths ndcates that tz1 t = 0. If we observe some labor tme allocated to each zone, whch occurs when the base camp s located n zone one and the satellte camp s n zone two, then 0 < tz1 t < 1. We can further restrct the lower bound of ths range, as the data show that herders never send more than 50% of ther labor force to satellte camps. Ths mples we wll observe a mx of tme spent n zone one and zone two when 05. tz1 t < 1. For the 389 observatons n the data set, full tme occupaton of zone two occurs for 38% of the observatons, a base camp n zone one and a 6 Ths tme perod begns after the drought nduced losses of 1992 and ends just after the drought nduced losses of In ths way, a full boom to bust cycle s represented. 7 As two of the 23 households have data for only 16 perods, the total sample sze s 389 observatons. 7

10 satellte camp n zone two s found for 32% of the observatons, and full tme occupaton of zone one s found for 30% of the observatons. An econometrc framework that can be used to estmate ths type of dependent varable s a tobt, wth censorng lmts at 0.49 and 1. Regressors ncluded n ths estmaton follow from the specfcaton of tz1 * n (6). Pasture avalablty s represented by two separate varables. The frst records ranfall levels, whch s assumed to be drectly correlated wth pasture avalablty. However, as ranfall s spatally varable, and ranfall data s only avalable for zone one, a second varable records the dfference between herder s subjectve evaluatons of pasture avalablty for each zone. 8 The herd specfc characterstcs υ and household specfc characterstcs λ are defned as follows. Herd characterstcs nclude a measure of speces composton measured by the rato of lvestock unts whch are large stock (camels and cattle) to those whch are smallstock (sheep and goats) for a gven herd. Ths varable s ncluded because speces dffer n management and productvty. A second herd characterstc s the number of pack camels n the household, as lack of access to pack camels may constran a herder s ablty to use zone two. Household characterstcs nclude the total number of household members; the number of unmarred household members between ages 10 and 30, whch are the prmary labor force for satellte camps; and the age and age squared of the household head. The dsturbance term u t conssts of unobserved household characterstcs π t, the mlk producton dsturbance ω t and the mlk share dsturbance term ψ t. 9 Results are presented for a model that ncludes dummy varables for ndvdual specfc fxed effects and one that does not recognze ndvdual specfc effects. The fxed effects model 8 Pasture avalablty for each zone records herder s subjectve evaluatons on a 1 to 5 scale, where 1 s very low, 3 s average and 5 s very hgh. The dfference used here s zone two mnus zone one. 9 Work s currently beng conducted on use of a SUR procedure to ncrease estmaton effcency. 8

11 can be wrtten tz1 = α + β' x + u. The model that does not recognze fxed effects assumes all t t t the ndvdual-specfc ntercepts α are equal to a constant β 0. Table 1: Land Use Decson: 0 s no tme spent n zone one, 1 s all tme spent n zone one. s.e. n parentheses Mean Tobt: Tobt: No Fxed Effects Fxed Effects Constant *** - (0.3784) Food Ad Delvery * 100 Tons (0.0198) (0.0207) Household Sze *** ** # members (0.0201) (0.0889) Young Labor *** # Unmarred (0.0212) (0.0891) Age of HH head ** ** Years (0.0144) (0.1155) Age 2 of HH head ** *** ( ) (0.0011) Herd Sze *** ** TLU (0.0018) (0.0042) Pack Camels * * # of pack camels (0.0276) (0.0642) Herd Composton *** * LS TLU/ SS TLU (0.0228) (0.0512) Ranfall Level * mm n perod (0.0009) (0.0009) Pasture Avalablty Dff ** [1,5] (0.0637) (0.0683) Log L * ndcates sgnfcant.10 level, ** ndcates sgnfcant at.05 level *** ndcates sgnfcant at.01 level The fxed effect specfcaton s sgnfcantly dfferent from the specfcaton that does not nclude ndvdual specfc terms, wth a LR statstc of 59.8 wth 23 restrctons. Table one provdes some evdence that there s an ncentve effect of current fxed-pont food ad dstrbuton programs. Although only the fxed specfcaton fnds ths result to be sgnfcant, both estmatons provde smlar coeffcents. The results on household sze and young labor force sze are mxed. The frst specfcaton fnds a sgnfcant postve coeffcent for household sze, whle the fxed effects model fnds a sgnfcant negatve coeffcent for household sze. The sgn on the coeffcent for young labor also dffers accordng to specfcaton. As there s very lttle varaton n household sze and young labor force over tme for a gven household, there s reason to queston the fxed effect result. Wth ths n mnd, we can nterpret the frst specfcaton as ndcatng an ncrease n household sze ncreases the famly s ablty to use the 9

12 extensve grazng zone. However, ncreasng the young labor force has an effect opposte than that antcpated, makng herders more lkely to stay n the zone around town rather than less. Both specfcatons fnd tme n zone one to be a convex functon of age. The frst specfcaton fnds the mnmum at 54 years whle the fxed effect model fnds the mnmum at 47 years. Increased herd sze s assocated wth decreased tme spent n zone one, although the coeffcent s small. Ths result s of some nterest, when compared to the mplcaton of the Hardn model that herd szes need to be lmted. 10 Wth regard to large stock, t appears that ncreasng the number of pack camels ncreases use of the extensve zone, but an ncrease n the rato of largestock to smallstock decreases use of the extensve zone. The coeffcents for ranfall levels ndcate these herders are no longer followng the tradtonal strategy. Increased ranfall levels are assocated wth ncreased tme n zone one, although ths result s not sgnfcant for the fxed effects model. As the tradtonal pattern requres vacatng the zone near town when ranfall ncreases, t appears ths practce has been abandoned. However, herders do exhbt some senstvty to dfferences n pasture avalablty between zones. Both specfcatons ndcate that as pasture avalablty n zone two mnus pasture avalablty n zone one ncreases, herders ncrease use of zone two, although ths result s not sgnfcant n the fxed effects model. Estmaton of the mlk allocaton share functon also proceeds by use of a tobt, n ths case one whch has a censorng pont at zero. Of the 389 observatons, 72% are at zero and 28% are between zero and one. Defnton of regressors follows the specfcaton for s * (.) n (6). Results are presented for a model wth fxed effects and a model wthout fxed effects. 10 Although further estmaton and smulaton wll be needed to explore ths ssue, t s possble that lmtng herd szes would nduce more herders to locate n zone one, thus ncreasng degradaton! 10

13 Table 2: Mlk Allocaton Share Functon: 0 s none marketed, 1 s all marketed. s.e. n parentheses Varable Means Tobt: No Fxed Effects Tobt: Fxed Effects constant *** (0.1025) - Herd Sze * TLU ( ) (0.0024) Mlk Prod ** ** l. / day (0.0140) (0.0133) Tme n Zone One *** *** [0,1] (0.0522) (0.0521) Household sze # members *** (0.0088) (0.0436) Log L * ndcates sgnfcant.10 level, ** ndcates sgnfcant at.05 level *** ndcates sgnfcant at.01 level The fxed effect specfcaton s sgnfcantly dfferent from the specfcaton that does not nclude ndvdual specfc terms, wth a LR statstc of 165 wth 23 restrctons. The specfcatons dffer n the sgn and sgnfcance of the coeffcent for herd sze, wth the fxed effects model dentfyng a postve and sgnfcant coeffcent. The two models both dentfy a postve and sgnfcant effect of ncreased mlk producton on sales. Most mportantly, both models ndcate mlk sales behavor s strongly nfluenced by the land use decson. Whle complete analyss of the ncentve effects of mlk marketng requres modelng the negotaton process between husband and wfe, t s reasonable to nterpret ths result as ndcatng that nfluencng the level of hs wfe s partcpaton n mlk marketng factors nto the husband s land use decson. 11 Mlk producton s estmated by assumng a Cobb-Douglas functonal form and conductng OLS estmaton n log-log form. Choce of regressors follows from the dscusson of equaton (1). A dummy varable for rany season s ncluded as herders evaluaton of pasture avalablty apples to a rany season and ts ensung dry season. The equaton estmated s as follows. α1 z1 z2 α2 (7) mp = α ( k ) ( tz1 pa + ( 1 tz1 ) pa ) exp( α rs + α hc + ω) Ths nterpretaton s further supported by data gathered on expendture patterns, as women spent 77% of mlk earnngs on food for the famly. 11

14 Table 3: Mlk Producton. s.e. are n parentheses Means OLS Mlk producton lters/day constant *** (0.4265) Herd Sze *** TLU (0.1072) Pasture Avalablty ** [1,5] (0.1384) Herd Composton TLU ls / TLU ss *** (0.1093) Rany Season Dummy *** (1,0) (0.0038) R * ndcates sgnfcant.10 level, ** ndcates sgnfcant at.05 level *** ndcates sgnfcant at.01 level For the study perod, herders report average pasture avalablty n zone one of 1.97 and n zone two of As ncreased pasture avalablty has a postve and sgnfcant effect on mlk producton, t appears that herders are wllng to trade off decreased mlk producton n order to resde closer to town. The results also ndcate herd sze has the expected postve and sgnfcant mpact on mlk producton. The somewhat surprsng result that the rany season dummy has a negatve and sgnfcant coeffcent may be related to anmal breedng perods. Fnally, the coeffcent for herd composton ndcates that ncreasng the rato of largestock to smallstock s assocated wth ncreased mlk producton. CONCLUSION The results of the estmaton secton ndcate that food and ncome producton strateges, herd characterstcs and household characterstcs play crtcal roles n nfluencng land use choces. They also ndcate that these herders are not followng the tradtonal strategy of vacatng zone one durng rany perods. However, there s evdence that herder s land use choce s nfluenced by the dfference n pasture avalablty between zones. Whle ths does allow some degree of self-regulaton n grazng pressure, ncentves assocated wth towns concentrate grazng pressure. In lght of these results, efforts to arrest degradaton around towns must be desgned n cognzance of food and ncome producton strateges, herd characterstcs, and household characterstcs that nfluence use of resources near towns. 12

15 BIBLIOGRAPHY Abel, N. O. J. (1993). Reducng cattle numbers on southern Afrcan communal range: s t worth t? Range Ecology at Dsequlbrum: new models of natural varablty and pastoral adaptaton n Afrcan savannas. R. H. Behnke, Jr, I. Scoones and C. Kerven. London, Overseas Development Insttute: Behnke, R. H. J. and I. Scoones (1993). Rethnkng Range Ecology: Implcatons for Rangeland Management n Afrca. Range Ecology at Dsequlbrum: New Models of Natural Varablty and Pastoral Adaptaton n Afrcan Savannas. R. H. B. Jr, I. Scoones and C. Kerven. London, ODI: Bot, Y. (1993). How Long can Hgh Stockng Denstes be Sustaned? Range Ecology at Dsequlbrum: new models of natural varablty and pastoral adaptaton n Afrcan savannas. R. H. Behnke, Jr, I. Scoones and C. Kerven. London, Overseas Development Insttute: Dodd, J. L. (1994). Desertfcaton and degradaton n Sub-Saharan Afrca: The Role of Lvestock. Boscence 44(1): Doran, M. H., A. R. C. Low, et al. (1979). Cattle as a Store of Wealth n Swazland: mplcatons for lvestock development and overgrazng n east and southern Afrca. Amercan Journal of Agrcultural Economcs 61: Ells, J. E. and D. M. Swft (1988). Stablty of Afrcan Pastoral Ecosystems: Alternate paradgms and mplcatons for development. Journal of Range Management 41(6): Hardn, G. (1968). The Tragedy of the Commons. Scence 162: Hellden, U. (1991). Desertfcaton-- tme for an assessment. Ambo 20: Herbst, J. (1993). The Poltcs of Sustaned Agrcultural Reform. Hemmed In: Responses to Afrca's Economc Declne. T. M. Callaghy and J. Ravenhll. NY, Columba Unversty Press. McCabe, J.T. and J. Ells. (1987). Beatng the odds n ard Afrca. Natural Hstory 96(1): Schwartz, H. J., S. Shaaban, et al., Eds. (1991). Range Management Handbook of Kenya. Narob, Republc of Kenya, Mnstry of Lvestock Development. Scoones, I. (1995). New drectons n pastoral development n Afrca. Lvng wth Uncertanty: new drectons n pastoral development n Afrca. I. Scoones. London, Intermedate Technology Publcatons Ltd.: USDA (1990). World Agrcultural Trends and Indcators, Washngton, DC, USDA. Westoby, M., B. H. Walker, et al. (1989). Opportunstc management for rangelands not at equlbrum. Journal of Range Management 42: