Role of Highland–Lowland Linkage as a Coping Strategy for Global Environmental and Socioeconomic Changes: The Case of Southeast Ethiopia

This study in Bale administrative zone, Oromia National Regional State, Ethiopia, aimed to investigate the vulnerability of livelihoods of highlanders and lowlanders to global environmental and socioeconomic changes and how highland–lowland linkage could function as a coping strategy. Multistage cluster sampling techniques were employed to select 403 sample respondents from the 2 agroecological regions. The primary data were collected using questionnaires, interviews, and focus group discussions. The data were analyzed by employing descriptive statistics and multiple linear regressions. The results indicated that both the highlanders and lowlanders were vulnerable to stresses, seasonality, and shocks due to natural hazards. The highlanders were vulnerable to crop failure and occasional floods, while the lowlanders were more vulnerable to drought, livestock disease, and conflict. However, they had devised various coping strategies, such as diversifying income sources and increasing mobility. Some of the coping strategies that were adopted necessitated a mutual understanding between the highlanders and lowlanders. Hence, strengthening complementarities between them by broadening their resource base could contribute to building resilient livelihoods for both communities, particularly the highly vulnerable lowlanders.


Background
Global sociopolitical and environmental changes have had a negative impact on the condition of agroecologies.Imbalances caused by demographic, socioeconomic, and political changes have intensified degradation trends that threaten the livelihoods of communities.Climate change is escalating such unfavorable trends by decreasing the capacity of nature and humans to adapt to future change (FAO et al 2011).These global changes are prompting communities to diversify their sources of livelihoods.This, in turn, enhances linkages between people in highland and lowland agroecologies (Gebreselassie 2016), as different agroecologies and livelihood systems are affected differently by climate change.
Highland and lowland regions throughout the world, particularly in developing economies, are interlinked through multifaceted economic and socioecological interfaces on various levels (Ives 2004).Inhabitants of these agroecologies have historically interacted with each other for survival (Gebreselassie 2016).Recognized interactions include exchange of food items and fodder, transport services, healthcare, and recreation facilities (Hug and Baccini 2002;Gebreselassie 2016).
Agroecological zones are important spatial units used to organize geographic space to understand its productivity (Chamberlin and Schmidt 2011).This categorization employs biophysical attributes of soil, topography, and climate to organize production systems into relatively homogeneous units (FAO 1978;Hurni 1998).Ethiopia's rural livelihoods are sensitive to agroecological zones (Dereje and Abeje 2018), with highland and lowland agroecologies engaging in different economic activities.Highlands are favored for a settled agricultural life (World Bank 2004), while lowlands are home to nomadic pastoralists (Mesfin 1988;Yanda 2003;Tolera and Abebe 2007;Workneh 2011).A subsistence mixed smallholder agriculture and pastoral system is the main means of livelihood (Workneh 2011: 4).
Scholars have debated the equilibrium of linkage between highlanders and lowlanders, with some arguing for unidirectional (Stoffel et al 2002;Yanda 2003) and others arguing for bidirectional linkages (Jodha 2002;Atkilt 2003;Ko ¨rner and Ohsawa 2005;Workneh 2011;Gebreselassie 2016).In this study, the relationship between highlanders and lowlanders was examined from a bidirectional linkage perspective.
Despite variations between highland and lowland systems in terms of ecology, resource endowment, economic condition, and infrastructure development, communities in both highland and lowland agroecologies are commonly affected by poverty, poor economic growth, and low productivity (Workneh 2011).Inhabitants of the lowlands are prone to drought-related issues, such as food insecurity and conflict over resource use, and there is a diminishing tradition of tolerance toward resource sharing (SOS Sahel Ethiopia 2008;Dinku 2018).Highland communities, which are known for their crop production, are extending their boundaries toward the grazing land of lowlanders, as their land is becoming unproductive due to overcultivation.Likewise, lowland pastoral communities are moving toward the boundary of highlanders as the productivity of their livestock declines due to overgrazing and water scarcity (Yanda 2003).Thus, if no mutual understanding between communities in highlands and lowlands is established, this could result in conflicts over the use of resources (Gebreselassie 2016).
In the Bale administrative zone, highland communities are known for their production of cereals, pulses, oil seeds, and vegetables, while lowland households rely on livestock rearing, honey and coffee production, as well as fruit cultivation (BoFED 2014).However, both highlanders and lowlanders are not self-sufficient and are vulnerable to food deficits induced by environmental degradation (Chamberlin and Schmidt 2011;Teshome 2013).Vulnerability is usually the product of 2 factors: exposure to risk and ability to cope (Majekodunmi et al 2014).The vulnerability of highlanders is associated with environmental shocks and stress like land degradation, land fragmentation, and poor agricultural practices.Yanda (2003) indicated that these problems in highland areas raise vulnerability to the extent that some farms can no longer sustain the household's social and economic needs.In addition, crop failures due to environmental shocks have also led to deteriorating living conditions among sedentary subsistence farmers (Tolossa and Baudouin 2004).
Conversely, the vulnerability of lowlanders is related to the decline in rangeland condition (Coppock et al 2018), continuing drought, increased competition for grazing lands, recurrent conflict (Dinku 2018), disordered livestock trade, limited regional market options (Devereux 2007), and widening restrictions on access to key resources (Nunow 2010).Moreover, constraints to productive and beneficial livelihood diversification, such as weak infrastructure, irregular income, cultural practices, and restrictive policies, also intensify the vulnerability of lowlanders (Dyer 2012).
Therefore, both highland and lowland households require alternative opportunities to reduce their vulnerability (Soini 2006).In designing strategies to reduce vulnerability, it is important to understand households' asset bases and active necessities.Importantly, because of their biophysical features, highlands and lowlands are endowed with different resource and production opportunities.Hence, one option to make their livelihoods more resilient against such shocks, stresses, and seasonality is strengthening their linkage, as it has important implications for the sustainable development of the two agroecological regions (Eriksen et al 2011).
Studies have focused on ecological (Ishikawa 2008) and economic linkages (Jodha 2002;Workneh 2011;Huber et al 2015;Gebreselassie 2016) but have failed to consider social, cultural, and political dimensions.To gain a holistic perspective on highland-lowland linkages, it is important to consider these dimensions.Thus, this study aimed to investigate the role of the highland-lowland linkage as a coping strategy to address ecological, economic, social, and political change at local and global levels.The study introduces a new approach to improving rural livelihood issues by increasing ecological, economic, sociocultural, and political linkages between highlanders and lowlanders and thus helps development policymakers to create strategies for sustainable development using synergies between highland and lowland agroecologies.
Highlanders and lowlanders have different agroecologies, with highlanders relying on crop cultivation and livestock rearing, while lowlanders rely on livestock nurturing.Highlanders respond to shocks by diversifying agricultural products, hiring land for limited periods, outmigrating, and seeking short-term employment (Yanda 2003;Tolossa and Baudouin 2004).Lowlanders respond by moving with their livestock to different grazing areas outside of their district (Gemtessa et al 2005;IIED 2009;Gutema and Jema 2014;Majekodunmi et al 2014).
In this study, a concurrent triangulation strategy of mixed approaches (Creswell 2003) was employed.Primary data were collected from households in the localities using structured questionnaires, interviews, and focus group discussions.Target populations were rural households in highland and lowland districts of Bale.Sample household heads were selected through multistage cluster sampling techniques.The 18 districts were categorized into 2 clusters of highland and lowland districts on the basis of mean elevational, agroecological, and socioeconomic characteristics (Table 1).
Accordingly, 6 highland and 12 lowland districts were identified.Two districts from each agroecological region were selected purposefully based on their relative location.To this effect, highland and lowland districts located adjacent to each other were selected on the basis of length of common administrative boundary shared and accessibility.Four rural kebele administrations (RKAs)-1 from each district-were drawn purposefully based on their relative location of being adjacent to each other (Figure 2).This was done to minimize external influence in studying linkages between districts (Yanda 2003;Huber et al 2015).
Sample size was determined by using the Yamane (1967: 886) formula, which assumes a finite population and simple random sampling and yields the optimum sample size for regression analysis.Thus, out of a total of 4337 households (Table 2) in 4 RKAs, the sample size with a sampling error of 5% and confidence level of 95% was 366.These values plus 10% contingency (Yamane 1967: 886) for nonreturn and nonresponse survey questionnaires added up to an optimum sample size of 403.This value was equally allocated to highland and lowland districts to capture balanced information and then proportionally distributed to the 4 RKAs.
Moreover, 12 key informants and 32 members for 4 focus group discussions were purposefully selected.Key informants comprised 3 development agent workers from 3 RKAs (Chirri, Mandera, and Buriya, as there was no such expert in Rira), 4 district agriculture/pastoral officers, and 5 elders, who were said to have detailed knowledge about the RKA.Participants in focus group discussions were a mix of young farmers/pastoralists, adult farmers/pastoralists, and female and male household heads, with different educational backgrounds.
The data were analyzed using descriptive and inferential statistics after cleansing and entering them into the SPSS program.Multiple linear regressions were used to identify determinants of livelihood outcome of households in highland and lowland agroecologies.This livelihood outcome was approached from the total annual income of households obtained from socioeconomic, geographic, and demographic variables (Huber et al 2015).The dependent variable, livelihood outcome, was regressed on the independent variables.The equation is expressed as where b 0 5 regression constant; b 1 5 regression slope; and y 5 livelihood outcome of households (annual income of households).The explanatory variables (x i ) included different demographic, economic, and farm characteristics.Household characteristics included: x 1 5 labor force in household (number); x 2 5 age of household head (years); and x 3 5 linkage status of household (HH) (index).Farm characteristics included: x 4 5 size of cultivated farmland  a) As the tenure is communal, it is not common to calculate landholdings per household.
The standard precipitation index (SPI) was used to examine trends of drought using drought indices calculator software (DrinC).Interpretation of the SPI results was made according to criteria established by Tigkas et al (2015).

Results and discussion
Highlanders and lowlanders have different categories of assets.Some assets are peculiar to highlands, others are specific to lowlands, and neither highlanders nor lowlanders are self-sufficient in these assets.This, in turn, calls for interdependency between these populations.Therefore, a highland-lowland linkage is an ideal strategy for highland and lowland communities to cope with various vulnerabilities.

Vulnerability of highlanders and lowlanders
Rural households engaged in various livelihood activities to build their assets to sustain themselves in hard times.However, households both in highlands and lowlands were vulnerable to varying trends, shocks, and seasonality.Thus, the degree of vulnerability and the use of linkage as a coping strategy for households in the 2 agroecologies were examined from the perspective of these trends, shocks, and seasonality.
Trends: Demographic (Figure 3) trends are changing in forward directions, with the population size of highlands and lowlands increasing due to natural increases and resettlement schemes.This has caused land fragmentation and an increase in landless rural youths, thereby reducing productivity and increasing vulnerability to shocks.Yanda (2003) also found this to be the case in Tanzania.
Shocks: Focus group discussions indicated that rural households were vulnerable to various shocks related to, for example, health, natural hazards, economic issues, and conflicts.Health shocks such as crop failure and livestock diseases were common in both highland and lowland agroecologies.Natural hazards, like flooding and drought, also affected their asset base and increased vulnerability to food insecurity and famine.Recurrent drought was common in lowlands of Bale, while drought sporadically occurred in the highlands (Figures 4 and 5).Fluctuations in the value of livestock in international markets also affected financial assets of households in the lowlands.In addition, the participants articulated that recurrent conflict between people of a locality (in this case, between Oromo and Somali) was also a shock responsible for enormous losses of livestock resources in the lowlands.The combined effects of these shocks made the livelihoods of lowlanders more vulnerable than those of highlanders in Bale zone.
Seasonality: Seasonality was another shock that affected the asset base of households.As agricultural activity is seasonal, their products and employment opportunities varied over the year.This, in turn, affected earnings, as confirmed by key informants from both highlands and lowlands.Highlanders identified autumn and spring as the major seasons when resource scarcity occurred due to lack and variability of rainfall.This view coincides with findings of Negussie (1999).Respondents indicated that households in highland and lowland agroecologies of Bale cultivated twice a year-in autumn and spring.However, the probability of drought occurrence (40% likelihood in autumn and 30% in spring) was found to be very high in the zone.One drought occurs approximately every 2 years, making Bale highly vulnerable to seasonal drought (Negussie 1999).Households whose livelihoods were entirely dependent on livestock rearing were also affected by seasonality, as availability of pasture is dependent on rainfall.During good production seasons, the market value for agricultural and livestock products was usually reduced.It was also reduced during the dry season, when the weight of livestock decreased due to the shortage of feed.Likewise, job opportunities related to agricultural activities were reduced due to seasonality of activities.

Highland-lowland linkage as a coping strategy
The livelihoods of households in highland and lowland agroecologies were endangered by various global changes and other external factors.The capacity of these households to endure such shocks and stresses depended on the range of their asset base.Thus, households with a wide range of assets and connectivity could withstand threats, while those with a narrow asset base and poor linkage were vulnerable to trends, shocks, and seasonality.Being aware of their vulnerability, both highland and lowland households devised different strategies to sustain their livelihoods.Accordingly, their linkage as a strategy to cope with environment-related shocks and food scarcity was identified and discussed.

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Coping strategies related to natural capital: Increasing trends in human and livestock population have undoubtedly created pressure on the existing natural capital, such as farming and grazing lands.In order to cope with these stresses, households adopted different strategies.Some coping strategies demanded cooperation between households of the 2 agroecologies.For instance, when lowlanders began to engage in farming activities as a means to diversify their income sources, they expanded their territory to adjacent highlands, as these localities are relatively productive due to the frequency of rainfall.
In some cases, this expansion of territory was welcomed by highlanders, but most of the time, it led to conflict.Likewise, other households moved their cattle to the farm fields of highlanders as a coping strategy.This was usually done in the dry season after highlanders harvested all their crops from their farm fields.This coping mechanism would be acceptable, if such movement indeed occurred after highlanders had collected their crops from their farm fields.

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Conversely, highlanders used to move their cattle to the communal grounds of lowlanders during the wet season when their farm fields were covered with crops.The remaining limited grazing lands in the highlands were reserved for draft and lactating animals, as well as young animals such as calves.Moreover, due to high pressure on existing arable land in the highlands, these households also expanded their farmland to adjacent communal lands of lowlanders where precipitation is relatively satisfactory.Hence, both highlanders and lowlanders coped with their livelihood vulnerability by sharing their natural capital.This is in line with the findings of Yanda ( 2003) and SHARE Bale Eco-Region (2017), who affirmed that natural resources, like water and grazing lands, contributed greatly to building resilient livelihoods for both communities.Thus, mobility between highlands and lowlands strengthened the linkage between them and was used as a coping strategy during shock and stress seasons.
Coping strategies related to financial capital: A common coping strategy adopted by households in highlands and lowlands was engagement in nonfarm and off-farm activities.These activities were reported by 31.8% and 42.7% of households in the highlands and lowlands, respectively.Petty trading activities upon which households' livelihoods depended included trading of cereals (9.7%) and livestock (29.3%) in local markets.Households bought and sold these agricultural products on the same date at the same market because they lacked warehouse storage space.Both cereals and livestock trading were predominantly practiced by households in the highlands.This may be attributed to the seasonality of their farming activities, as their production entirely depended on rainfall.Moreover, these households engaged in informal activities like producing and selling cultural drinks (7.7%), collecting and selling medicinal plants (0.7%), renting pack animals (0.5%) and motorbikes (0.5%), and grain mill services (0.5%).Production and consumption of traditional drinks were common among households in the highlands, while producing and selling traditional medicines were practiced by both highlanders and lowlanders.Renting of pack animals, such as horses, was a common business among households in the highlands, particularly in Goba district, as it is connected to tourism.Moreover, renting of motorbikes was commonly practiced both by highlanders and lowlanders, but it was more important for lowlanders, as they utilized it for informal trading.In addition, though their contribution was insignificant, households in both the highlands and the lowlands also engaged in cottage industries, such as carpentry (2.5%), pottery (2%), weaving (2%), and blacksmithing (0.7%).Thus, highlander and lowlander

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households employed labor activities to diversify their income sources before food scarcity, but they also adopted other coping strategies in response to food scarcity.
• Selling of assets: A total of 18.9% of sampled respondents coped with food scarcity by selling assets partly or entirely, depending on the extent of the problem.Participants of focus group discussions in Rira and Buriya RKAs affirmed that households started to sell their assets sequentially from less productive to highly productive assets.Households in the highlands began by selling cereals reserved for later use and seeding.Then, they gradually passed to selling small livestock, like goats, sheep, young bulls, and heifers.Selling lactating and plow animals was a last-resort coping strategy, as they are prime production assets.This agrees with the findings of Tolossa and Baudouin (2004).Likewise, participants in focus group discussions in Mandera and Chirri RKAs revealed that households in the lowlands cope with such stresses by selling assets, mainly livestock.Selling livestock in exchange for cereals was common among lowland households, but what is important is the size of the livestock sold.Hence, market centers played a dominant role in linking highlanders with lowlanders as a livelihood coping strategy during stresses.• Migration: Both highlanders and lowlanders adopted migration as a coping strategy when food was scarce over an extended period.In such cases, some members of the household were forced to migrate to other localities, particularly to the nearby urban centers in the highlands.
These migrants helped themselves, and their family members who stayed at home, by working in these centers.Focus group discussions showed that migration between highlands and lowlands in search of job opportunities had 2 aspects: outflow of workforce and inflow of remittances, helping to reduce livelihood vulnerability.This finding is in agreement with the findings of Banskota and Sharma (1999).Hence, migration between the 2 spatial units helped as a coping strategy against livelihood vulnerability.• Loans and aid: Based on their social capital, rural households in the highlands and lowlands used to get loans from their relatives and networks as a coping strategy.A total of 30.8% of households looked for loans from their connections: 22.3% were highlanders, while the remaining 8.4% were lowlanders.Items loaned included cereals, livestock, and money.Participants of the focus group discussions revealed that rural households, both in the highlands and lowlands, have a habit of supplying cereals as free gifts or loans during periods of food insecurity.This depended on their social cohesion.Lowland households who had good social connections with highlanders could easily get such gifts and loans.Likewise, highlanders with good social linkage with lowlanders got access to gifts and loans of milking cows.Such a tradition was also identified by Tolossa and Baudouin (2004) in northeastern Ethiopia among cultivators and pastoralists in Borkena Valley wetlands.Social cooperation was also observed among households of the same agroecology.Moreover, these

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households loaned money to each other based on trust, which is an important social capital among rural households in Ethiopia.Lowland households in the study area were most dependent on government aid, with 41.4% being lowland households.Nongovernmental organizations provided money and food items, but not in highland districts.Around 12% of households employed other coping strategies.In general, rural households both in the highlands and lowlands were vulnerable to food-scarcity-related stresses.However, lowlanders were more vulnerable to such shocks than highlanders because their agroecology is fragile, and their livelihoods are less diversified.As a result, both highlanders and lowlanders used their social capital as a coping strategy against livelihood vulnerability.• Source of income diversification as coping strategy: Household income source was a major determinant of livelihood vulnerability and choice of coping strategies.Livelihood outcomes of highland and lowland households were influenced by a range of sociocultural, geographical, and economic factors (Bazezew et al 2013).Thus, to identify significant determinants of a household's income in the 2 agroecologies, multiple linear regression analysis was employed (see Equation 1).Six variables-labor force, size of cultivated plot, amount of cereal production, age of household head, highland-lowland linkage status of households, and livestock resources-were fitted to regression models employing the enter method.The results from the 6 variables entered to the model gave 4 variables with high significance levels (P , 0.05) for both highlanders and lowlanders.The coefficient of determination for highlanders and lowlanders was 0.539 and 0.44.1, respectively, implying that about 53.9% and 44.1% of variation in annual household income of highlanders and lowlanders was explained by these variables.This result suggests that there are other explanatory variables.Collinearity diagnosis results also suggested that family size is highly correlated to age and economically active age group members, and, therefore, it was removed to keep the assumptions of the model.Thus, size of cultivated plot, amount of cereal production, linkage status of households, and number of livestock resources were found to be significant determinants of household annual income in the highlands.
For households in lowland agroecology, number of people in the labor force, size of cultivated plot, age of household head, and number of livestock in TLU were factors that determined the household annual income (Table 3).This implies that these variables influenced the livelihood outcomes of households in both agroecologies differently.

Conclusion
Highlanders and lowlanders were vulnerable to seasonal shocks and shocks caused by global changes.Lowlanders were more vulnerable to drought, conflict, livestock disease, and crop pests, while highlanders were more vulnerable to shocks and seasonality.Coping strategies such as diversification of sources of income have been adopted by both communities.Resources that strengthen the linkage between communities of the 2 agroecologies should be developed and conserved to build resilient livelihoods and promote sustainable development.Researchers should use quantitative data to measure the impact of linkage on the livelihoods of both communities.
We are indebted to all individuals who participated as field guides, enumerators, and respondents in the study.

FIGURE 3 FIGURE 4
FIGURE 3 Trends of human population growth by agroecology from 2002 to 2017.

FIGURE 5
FIGURE 5 Spatial distribution of drought in Bale zone.SPI, standard precipitation index.

TABLE 1
Ecological and socioeconomic characteristics of the sampled highland and lowland districts.

TABLE 2
Distribution of sample respondents among RKAs.

TABLE 3
Coefficients of multiple linear regression for highlanders and lowlanders.
Note: The dependent variable is the total amount of income obtained from agriculture-based livelihoods.High significance values (P , 0.05) are highlighted in bold script.SE, standard error.