Keywords

Introduction

Northern Ethiopia has historically been under extreme demographic influence, civil war, and climate change that increased the occurrence of drought and extreme weather variability and concomitant environmental degradation (Conway 2000). Perhaps nowhere in the world is land degradation problem more manifest than in the marginal highlands of northern Ethiopia (Hengsdijk et al. 2005), with a huge cost and economic implication (Haregeweyn et al. 2008a). Some of the worst human calamities caused by drought and subsequent famines have been reported in the northern Ethiopian regions of Tigray, Amhara, and Afar, so much so that the region has been associated with famine and misery in popular imagination. Such challenges have made people and government in northern Ethiopia to implement steady ecosystem-based adaptation (EBA) and community-based land rehabilitation and conservation programs, with impressive and internationally recognized success (Bewket 2007). The interventions implemented in northern Ethiopia utilize biodiversity and ecosystem services to support climate change adaptation and enhance environmental rehabilitation, making them typical cases of EBA (Munang et al. 2013).

Nonetheless, despite northern Ethiopia being repeatedly recognized for its efforts-impacts of its interventions (https://www.worldfuturecouncil.org/p/champions/), information on what actually has been changed and what has been achieved is only available in the form of results of dispersed studies that evaluate the impact of different interventions on wide variety of environmental and social variables (Gebremeskel et al. 2017). So far, impacts brought about through different interventions, the challenges encountered, and possible future solutions have not been analyzed and articulated in a way that would enable sharing of experiences with other communities (Gebremeskel et al. 2017). Therefore, studies undertaken on different EBA interventions in the Tigray regional state with the objective of identifying understanding the EBA interventions, their impacts, challenges encountered in implementation, and recommendations for better successful implementation in the future. Moreover, the study contributes towards evidence on effectiveness of EBA that is generally limited worldwide and concentrated only in developed countries (Doswald et al. 2014) and provides an analysis of different factors that affect the effectiveness of EBA interventions based on cases from northern Ethiopia.

Materials and Methods

Description of the Study Area

Tigray regional state is one of the nine regional states in Ethiopia located at the northern most extreme of the country (Fig. 1) between 12°15′ and 14°50′N and between 36° 27′ and 39° 59′E with an area of 80,000 km2. It is surrounded by Sudan in the west, Eritrea in the north, and the Ethiopian regions of Amhara and Afar in the south and east, respectively. Tigray is characterized by undulating terrain and steep slopes with altitude varying from 500 to 4000 m.a.s.l. (Gebremeskel et al. 2017). The agroecology is semi-arid with distinct dry and wet seasons and rainfall ranging 200–1000 mm and with an average annual temperature of 18 °C (Hagos et al. 1999).

Fig. 1
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The Tigray regional state showing its administrative units

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The land use types dominant in Tigray include croplands, exclosures, remnant forests, villages, and built-up areas. Thirteen major soil types are identified in Tigray: cambisols, rendzinas, lithosols, acrisols, fluvisols, luvisols, regosols, nitosols, arenosols, vertisols, xerosols, solonchaks, and andosol (Nyssen et al. 2008a). The geological formations consist of Precambrian metavolcanics and Mesozoic sedimentary rocks such as Adigrat sandstone, Antalo limestone, Agula shales, and Amba Aradam sandstone, which in turn are intruded by Cenozoic dolerite dykes/sills (Haregeweyn et al. 2008b).

Tigray has a population of 4.4 million growing at 3% annually (CSA 2010). The farming system is dominated by small-scale rainfed agriculture, which utilizes traditional crop and livestock production technologies (Hagos et al. 2016). Approximately 90% of the population depends on the centuries-old plow-based subsistence cultivation, currently having 1.2 ha average landholdings per household (Pender and Gebremedhin 2007). Agriculture contributes to 60% of the regional total gross domestic product (Hagos et al. 2016). Dominant cereal crops grown are tef (Eragrostis tef), barley (Hordeum vulgare L.), wheat (Triticum sp.), sorghum (Sorghum bicolor), and maize (Zea mays), accompanied by leguminous crops such as field peas (Pisum sativum), chickpeas (Cicer arietinum), and horse bean (Vicia faba). Gesho (Rhamnus prinoides). Cattle, sheep, goat, equines, beehives, and poultry are dominantly found in livestock types in Tigray.

Methods

Selection of Studies and Records

Published studies were searched from the Web of Science and Google Scholar Databases using relevant key words. Moreover, gray literature or office and field reports by different organizations working in the EBA issues in the Tigray, Masters/MA, PhD level unpublished theses and dissertations have also been included. Though there was no restriction in the years for publication of studies and reports, most of the 170 identified studies fall within the years 1997–2017. Only studies or peer reviewed publications that have been published in journals indexed by the Web of Science, Scopus, African Journals OnLine, and other legitimate indexing services were included, and those published in the so-called predatory journals have been excluded, as their quality have been repeatedly questioned (Balehegn 2017a).

Evaluation of EBA Interventions

EBA interventions were first categorized into any of the six categories namely: (1) Biological Rehabilitation (BR): Those that intend to enhance or improve the biological potential of degraded grazing lands, farmlands, etc.; (2) Conservation Agriculture (CA): Types of agriculture or farming that tried to maximize the conservation of moisture for improved yield; (3) Integrated Watershed Management (IWM) catchment or watershed level approaches that implement combinations of many interventions for an overall ecological and livelihoods improvement; (4) Soil Fertility Improvement (SFI), which included variety of interventions that aim to improve the fertility status of degraded farmlands; (5) Soil and Water Conservation (SWC), interventions aimed at conserving soil and water or protecting soil from erosion; and (6) Water Harvesting and Production (WHP), interventions that intend to conserve water from loss or extract more water for agricultural and other uses. The observed impacts of EBA interventions were also categorized into 11 general categories (Fig. 5) namely: (1) Enhanced drought and climate change adaptation (EDCCA), (2) Enhanced soil characteristics (ESC), (3) Enhanced vegetation (EV), (4) Improved carbon stocks (ICS), (5) Improved crop yields (ICY), (6) Improved income and livelihoods (IIaL), (7) Improved livestock productivity (ILsP), (8) Improved wildlife diversity (IWD), (9) Improved water harvesting and use efficiency (IWHUE), (10) Reduced runoff and increased sediment deposition (RRISD), and (11) Others. Moreover, for most of the EBA interventions, main challenges encountered during the implementation, solutions recommended or implemented have also been identified (Table 8).

Results and Discussions

Types of EBA Interventions

A total of 30 types of EBA interventions including SWC (n = 16) followed by WHE (n = 10), BR (n = 10), CA (n = 7) and SFI (n = 3) have been reported. The typology of the different interventions is given in Fig. 2. The EBA interventions according to the percentage of cases reported (total number = 402) are SWC (62.69%), BR (18.41%), WHP (7.46%), SFI (6.22%), CA (3.48%), and IWM (1.74%) (Fig. 3). The larger diversity of SWC interventions is because of the diverse agro-ecological setting in northern Ethiopia that requires different solutions. Moreover, soil erosion and land degradation have always been the most important environmental problems (Hurni 1988) with serious economic consequences such as, for example, causing a loss of 3.4 million Euros per year, just from the erosion caused loss of N and P in Tigray (Haregeweyn et al. 2008a). As a result therefore, SWC interventions have been the commonest types of EBA interventions in northern Ethiopia, with about 522, 600 ha of land already covered by some form of SWC interventions, mainly stone bunds from 1991 to 2002 (Nyssen et al. 2007). Exclosures are the second most commonly implemented and studied interventions. Currently, there are about three million hectares of land under exclosure management all over Ethiopia (Lemenih et al. 2014), with most of it (around 1.2 million hectares) of exclosures being in Tigray (Tetemke et al. 2017).

Fig. 2
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Typology of ecosystem-based adaptation techniques implemented in northern Ethiopia

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Fig. 3
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Percentage cases of studied interventions. SWC Soil and water conservation, WHP Water harvesting and production, SFI Soil fertility improvement, EA Ecological Agriculture, BR Biological rehabilitation, IWM Integrated watershed management

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The description, purposes, and sites for implementation of the different EBA interventions is given in Table 1. Some examples graphical representations of EBA interventions are also given in Fig. 4.

Table 1 EBA interventions implemented in northern Ethiopia and their descriptions
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Fig. 4
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Different EBA interventions implemented in Tigray (Top row right to left: Gulley treatment, stone bunds, integrated gulley treatment, zero-grazing (cut and carry from exclosures). Middle row: Reservoirs, hand-dug wells, and river diversion). Bottom row: Treated gulley, exclosure enriched with drought-tolerant halophytes, earth sided deep trenches, the derdero system of plowing)

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Impact of Interventions

The most commonly reported impact is reduction in runoff and increase in sediment deposition (461 cases) followed by improved crop yield (61 cases) and enhanced vegetation (49 cases) (Fig. 3). Other impacts, reported to a lesser extent also included impacts on income, livestock productivity, soil fertility, carbon stocks and others (Fig. 3).

Apart from limited number of studies (30 cases), which tried to quantify and demonstrate the economic or livelihood impact of interventions, most studies demonstrated only biophysical impacts on soil, vegetation and water. This is probably because of the methodological difficulties of differentiating the impact of the EBA interventions on the livelihoods and income (Haregeweyn et al. 2015) but is critical problem because, the emphasis on biophysical impacts with little consideration on the social and economic benefits of interventions makes it difficult to provide evidence for convincing policy makers in expanding the implementation of the EBA practices and popularizing the practices among local communities (Awulachew et al. 2005). Even when it is currently difficult to quantify economic and livelihood benefits, as ecological improvement will take time to manifest as livelihood improvement, it is important that modeling studies be undertaken to generate evidence for livelihood impacts of interventions, unless and otherwise it will be difficult to convince farmers (Balana et al. 2010).

Impacts of Biological Rehabilitation

Positive impacts as a result of the most common biological rehabilitation interventions – exclosures – include improvements in: litter accumulation (1802–2108.57%), total organic carbon (15–64%), available Nitrogen (187–5125%); soil phosphorus (290–1150%), and other soil chemical characteristics (Table 2). Similarly, exclosures have resulted into improved vegetation attributes including: herbaceous cover (329.27%), herbaceous species diversity (31–50%), woody species cover (436%), woody species diversity (50–81%), and other vegetation attributes including species richness, vegetation density, basal cover and ground cover, and bird and mammal species diversity (Table 2). Reduction in soil erosion (46–79%), runoff (83–95), and improvement in other soil and water variables such as rain percolation, and sediment accumulation are also some of the impacts of exclosures that have been measured in various studies (Table 2).

Table 2 Impacts of biological rehabilitation interventions in northern Ethiopia (Sampled studies showing impacts on various variables)
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Though limited in numbers, economic-related impacts have also been quantified for exclosures. These include improvement in yield of economically important products such as Frank incense from Boswellia paprifera tree (43.9%), improvement in livestock productivity (20%), and overall increase in net value of land as a result of conversion to exclosures (28%). Though numerical quantification is lacking, exclosures have also improved the income of poor families through the production of honey in exclosures and sell of grass (Meaza et al. 2016). In fact, a study by Babulo et al. (2009) indicated that products from exclosures including (honey, fuel wood, grass, etc.) account for 15% of the overall average forest environmental income in Tigray.

All these improvements observed as a result of exclosure are mainly due to removal of overgrazing that not only cause removal of vegetation but also physically disturb soil structure making soil unsuitable for natural recruitment, ultimately contributing to land degradation. In the specific case of northern Ethiopia, traditional free-grazing system has contributed to the steady degradation of land that has taken place in the highlands of Ethiopia for centuries (Mekuria et al. 2007; Taddese 2001) and has resulted in continuous decline in the availability of livestock feed and other ecosystem services from natural rangelands (Gebremedhin et al. 2004). Free-grazing system did not only result in increased land degradation but also has limited the effectiveness of human endeavor in rehabilitating degraded areas through the physical destruction of soil and water conservation structures (Meshesha et al. 2012). Many communities in northern Ethiopia have therefore implemented the exclosure intervention and have voluntarily established traditional local by-laws which helped in enforcing strict protection of exclosures from livestock and human disturbance (Yami et al. 2013). Economic and ecological benefits accrued from exclosures, however, depend on the age of exclosures, where at least 7 years of exclosure is needed before significant improvements in soil physical and chemical characteristics can be detected (Mekuria et al. 2017). Therefore, it is important for planners and communities to understand that benefits may not be realized with in short period of time.

Similar to exclosures, other biological rehabilitation interventions including silvopastures, agroforestry, and plantations or reforestation have resulted in improvements such as increase in soil nitrogen, soil carbon, vegetation attributes, and farmland and livestock productivity, and even income (Table 2). These interventions act by increasing the number of multipurpose trees planted on farms, farm boundaries, wastelands, hillsides, and other similar areas. Specific multipurpose trees such as Ficus thonningii (Balehegn 2017b), Feidherbia albida (Gelaw et al. 2015a), Acacia etbica (Yayneshet et al. 2008) introduced in agroforestry and silvopastoral systems have been observed to result in ecological and economic improvements such as improved soil fertility (Gelaw et al. 2014), livestock productivity (Balehegn et al. 2014), and income (Meaza et al. 2016).

Impact of Conservation Agriculture Interventions

The different quantified positive impacts of conservation agriculture include reduction in runoff by Derdaro (49–82%), mulching (64.44%), permanent beds (60.49%), Shilshalo (41.65%), tied ridges (56%) and combination of tied ridges, straw mulch, and effective microorganisms (80.85%) (Table 3). Reduction in runoff has also resulted in the expected reduction in soil loss from farmlands at rates of 53–78.5% for Derdero, 78.89% for permanent beds, 21–61.03% for Shilshalo, and 87% for combination of Terrrewah, straw mulch, and effective microorganisms (Table 3). The different conservation agriculture interventions and their combinations have also resulted in reduction in loss of soil nutrients including nitrogen and phosphorus. All these positive impacts have eventually resulted in an increase in yields of different crops including Derdaro (34–48%), Shilshalo (17.88–21.35%), and tied ridges (80–94.89%) (Table 3).

Table 3 Impact of conservation agriculture interventions in Northern Ethiopia
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These improvements are achieved because the simple interventions of changing how land is tilled resulted in artificially made micro-basins that conserve soil moisture and reduce the loss of soil and nutrients from farmlands (Brhane et al. 2006). For instance, a simple tide ridging during plowing resulted in an increase of soil water content by 45.5% (Brhane et al. 2006). Similar improvements in water balance, crop productivity, and reduction in runoff and soil loss, due to conservation agriculture interventions, have also been observed elsewhere (McHugh et al. 2007).

Impact of Water Harvesting Interventions

Various water harvesting interventions including micro-dam reservoirs, river diversion, ground water production, and various catchment-level water harvesting structures including deep trenches, hand-dug wells (Woldearegay and Van Steenbergen 2015) have improved the available water for agriculture and domestic use, while reducing runoff and soil loss. The increased water availability for agriculture has inevitably resulted in an increase in income of up to 50% (micro-dam reservoirs), 50% (river diversion), and 50% (ground water development schemes) (Table 4). Catchment level integrated water harvesting schemes have also resulted in decrease in runoff by 43% and catchment level sediment yield by 54.5% (Table 3). Other reported impacts include increase in crop yields ranging from 71% to 233.3% for various crop types as a result of implementation of spate irrigation schemes (Table 3). Spate irrigation’s positive impact is particularly important because there is about 9265.95 million meter3 of flood water and 661853.6 ha of arable and 695,000 ha of communal land that can be irrigated using spate irrigation (Yazew 2015).

Table 4 Impact of water harvesting and production technologies
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Impacts of Soil and Water Conservation

The most common types of soil and water conservation interventions (stone bunds), have resulted in improvements of: soil organic matter content (10–100.1%), soil nitrogen (5.71–100%), available phosphorus (1.4–31%), yields of various crops (4.78–25%), value of crop productivity (2.53%), net return (30%), and reductions in runoff (22%) and soil loss 64.9% (Table 5).

Table 5 Impacts of soil and water conservation interventions
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Other improvements observed include reductions in gulley head retreat rate (100%), runoff (11.11–55.56%), and number of destroyed dams (2.82%), due to interventions of subsurface geomembrane dams, check dams with vegetation and boulder-faced check dams, respectively (Table 5).

Impact of Soil Fertility Improvement Interventions

T he different soil fertility improvement interventions have resulted in various positive impacts. These include improved grain yields of 10.39–103.08% (use of compost), 63.7–71.99% (use of bioslurry), and 125.76% (use of reservoir sediment) (Table 6). The use of compost and bioslurry is not only a cheap source of fertilizers but also that their use helps in management and removal of domestic and farmland wastes, which would otherwise be source of health concerns in rural areas (Beyene 2011). Moreover, plants that are normally considered noxious weeds, such as Parthenium hysterophorus, Datura stramonium, and Argemone mexicana, have been have been used for composting resulting in both improved soil fertility while at the same time removing weeds (Tedla 2010).

Table 6 Impact of soil fertility improvement interventions
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Some EBA soil fertility management options may not be able to improve crop productivity as compared to the inorganic fertilizers, where crop yields have been observed to decline as inorganic fertilizers are replaced by composts (Table 6). However, even though inorganic fertilizers cause a boost in crop yields in the short term, their prolonged and intensive use causes decline of agro-biodiversity and over all soil and ecological health (Hadgu et al. 2009). Therefore, owing to the desirable long-term impacts they have, as compared to inorganic fertilizers, and the significant contribution in crop yields, there is a potential for the use of EBA practices in soil fertility improvement such as composting and bioslurry.

Impact of Integrated Watershed Management Interventions

Observed impacts of IWM interventions include reductions in: runoff (7.9–94%), erosion (89%), soil loss (32–37%), sediment yield (77%), and percentage bareland (75%) and increments in: sediment deposition (22.41%), percentage irrigated land (3077%), forest cover (142.3–202.4%), bush land (72%), and yield of various crops (60–100%) (Table 7). The runoff and erosion rates observed by the reviewed studies have shown a tremendous improvement from the 42 tons/ha that has been recorded before the start of the integrated watershed management interventions (Hurni 1988). Most of the positive improvements reported for northern Ethiopia are similar to the impacts of IWM reported elsewhere (Mekonen and Tesfahunegn 2011). A qualitative assessment by Michael and Waters-Bayer (2007) also reported similar observations of increased vegetation cover, more water infiltrated into the soil, reduced siltation, and increased crop yields. Generally speaking, because of the various integrated interventions, the effect of recurrent drought and extreme land degradation is effectively offset that the Tigray regional state is now more productive and greener than it used to be some 145 years ago (Nyssen et al. 2014).

Table 7 Impacts of integrated watershed management interventions
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Challenges with EBA Interventions and Future Directions

Though the changes brought about by the different EBA interventions are impressive and have been confirmed and reconfirmed by many studies, certain issues threaten the sustainability of the positive benefits of the interventions exist. The most important challenges include challenges of mobilizing public support, due to limited immediate economic benefits from interventions and a misguided approach for recruiting popular support and specific technical challenges with some interventions. While the challenge with the approach of recruiting popular support is explained below, specific technical challenges and recommended solutions are outlined in Table 8.

Table 8 Main challenges of important EBA interventions in Tigray regional state and recommended solutions
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Challenges on Mobilizing Public Support

In a review of soil and water conservation interventions in Tigray, Gebremeskel et al. (2017) concluded that voluntary popular participation in the form of free labor days (mid to late 1980s) and then work for food program in the 1990s, accompanied by integration of disciplines (social, technical, and institutional) were most important reasons for the observed impressive success. Similarly, Nyssen et al. (2004a) indicated that farmers participate voluntarily, because in highly degraded areas like northern Ethiopia, farmers are left with no other alternatives, except improved land management or rehabilitation.

However, Segers et al. (2008a) argued that local farmers’ mass participation is more of a support to the political agenda or conformity to popular practice than an understanding of or anticipation of the financial benefits to be accrued from participating in such schemes. In other words, it means that farmers accept interventions even knowing fully that they are not suitable for them, perhaps, why some very ambitious projects like the “horeye” water harvesting, despite obviously destined to fail, did not face any opposition by farmers. The Tigray regional administration was mainly successful in gaining popular support for its land rehabilitation projects by tapping into the common history and legacies of solidarity during the armed struggle of the Tigrian People’s Liberation Front (TPLF) against the “Dergue” military regime, than by convincing farmers of the economic benefits of the projects (Segers et al. 2008a). It has been demonstrated earlier in this chapter, the number of studies that showed economic or livelihood benefits is also very limited (Fig. 5). This makes it difficult to make economic arguments for further dissemination of successful interventions. It is, however, also important to note that economic or livelihood benefits need time to manifest and that implementers need to subsidize farmers’ efforts until economic incentives can attract voluntary local engagement (Gebremedhin et al. 1999). Secure land tenure rights can also reinforce private incentives to make long-term investments in soil conservation (Gebremedhin and Swinton 2003). Moreover, it is important to raise the Tigrean masses awareness that the interventions are ultimately meant to increase income and productivity, and are not orders that they have to blindly follow, as such a thinking would improve the household level adoption of these technologies, which is currently either lacking or very limited (Segers et al. 2008a).

Fig. 5
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Number of cases of evidences for different positive impacts. EDCCA Enhanced drought and climate change adaptation, ESC Enhanced soil characteristics, EV Enhanced vegetation, ICS Improved carbon stocks, ICY Improved crop yields, IIaL Improved income and livelihoods, ILsP Improved livestock productivity, IWD Improved wildlife diversity, IWHUE Improved water harvesting and use efficiency, RRISD Reduced runoff and increased sediment deposition

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Conclusion

In this chapter, we critically reviewed studies on decades of extensive EBA adaptation practices, implemented in one of, hitherto, the most ecologically fragile, hunger, and poverty-ridden corners of the world that has been repeatedly plagued by recurrent drought and extreme weather variability. The review includes 170 publications on 30 different types of EBA interventions in 400 sites in Tigray. Reviewed studies indicated that Tigrian farmers, together with the Tigray State Government of Ethiopia, their donors and development partners have demonstrated that through dedicated, evidence-based interventions, it is not only possible to beat the problems of land degradation, recurrent drought, extreme weather variability but also turn around the challenges and convert land into highly stable productive ecosystems. Interventions spanned variety of simple, low cost, locally available ecosystem-based adaptation interventions that can generally fall into six categories, namely, biological rehabilitation, conservation agriculture, integrated watershed management, soil fertility improvement, soil and water conservation, and water harvesting and production interventions. Quantified and reported impacts of the EBA included in general, improvement in biophysical ecological variables such as reduced runoff, increased soil deposition, improved vegetation cover etc., (63.93% of cases), improvements in crop (8.46% of cases), improvement in livestock yields (1.6% of cases), and income/livelihoods (4.16% of cases).

Despite wide spread reported improvement in biophysical variables such as reduced runoff, reduced soil erosion, improved soil fertility, etc., improvement in income or livelihoods has only been reported 4.16% of cases. This is probably caused by methodological difficulty for quantifying economic or livelihood impacts, which in turn limits the ability to make livelihood or economic argument for promoting the different EBA interventions. Therefore, there is a need for developing tools that enable the generation of evidence on economic impact of interventions and capitalizing on EBA interventions that would enable the maximum economic or livelihoods benefits to local farmers.

While popular participation has been repeatedly cited as an important reason for successful implementation of the EBA interventions, household level or private adoption of the interventions still remains very limited. Almost all practices are implemented in communal or government land. This puts a question as to the motive of farmers in participating in the implementation of interventions. Though, many indicated that farmers participate voluntarily, by sometimes offering free labor days, there is evidence that this is mainly behavior of conformity, rather than a need-based voluntary involvement. This might explain why most of the interventions are lacking from private land or household-based interventions. This is important because, without popular household-based adoption, the sustainability of the interventions could be under question. Therefore, it is important to raise awareness on the short and long term economic or livelihood benefits of the EBA interventions, so that individual farmers can adopt them.

Finally, the types of EBA and land rehabilitation interventions, challenges faced and solutions implemented give important lessons for replicating the success in northern Ethiopia to similar places elsewhere, with similar challenges.

Cross-References