Restoring Ethiopian Drylands at Scale
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Restoring Ethiopian drylands at scale Jason Sircely Livestock Systems and Environment International Livestock Research Institute (ILRI) PO Box 5689 Addis Ababa, Ethiopia [email protected] Introduction communal lands from grazing-induced soil Improving the productivity of erosion and compaction. Often located on drylands in Ethiopia supports government steep unproductive catchment slopes above initiatives to increase livestock and crop croplands to increase infiltration and base production, increase food security, and flow to the croplands below, animals are enhance regulation of water flows. Many excluded for all or portions of the year drylands in Ethiopia are moderately to (especially the rainy season), with forage severely degraded and require restoration, cut and removed from the exclosure during and the productivity of drylands in better closure periods (Nedessa et al. 2005). condition can be maintained or improved. Exclosure management regimes are Some parts of the country have seen primarily regulated by local institutions, significant restoration success—including including village councils and other grazing exclosures and soil and water informal institutions, which create by-laws conservation—while other areas have seen for exclosure use and enforcement, often few gains. There exists major potential for linked to the local government legal system up-scaling restoration in Ethiopia (Tongul (Yami et al. 2011). In Tigray, recurrent and Hobson 2013), however it is not often droughts and the need to improve land clear how likely various restoration options management to increase water supply to are to succeed in new areas. The downslope cropping areas (Gebreyohannes biophysical and social context of a specific and Hailemariam 2011) have driven area significantly affects the success of exclosure establishment, aided at times by restoration options, and the degree to which pre-existing organizational linkages from options require adaptation to fit local needs the military resistance to the Derg regime. (Coe et al. 2014). The goals of this review In Hararghe in Oromia, drought and are to: (i) identify options with proven shortage of grazing land were the main success and high potential for up-scaling in factors behind widespread expansion of Ethiopian drylands, (ii) analyze factors exclosures over recent decades underlying relative success in different (Gebreyohannes and Hailemariam 2011). agro-ecologies and under different Exclosures have successfully institutional conditions, and (iii) assess improved production of forage as well as options that may have high potential in wood, yet have also generated a variety of areas and systems without well proven other benefits, including soil conservation, successful options. Since it is difficult to improved soil fertility, C sequestration, and disaggregate the specific effects of the improved hydrological flows. Generally, multiple technical and institutional options exclosures reduce soil erosion and flood that have successfully improved natural intensity, increase downstream water yield, resource management in Ethiopia, and in some cases revive springs and restoration options are assessed from an increase the ground water table (Nedessa et integrated perspective. The review focuses al. 2005). Most detailed information on especially on options currently being up- exclosure effects on soils and water comes scaled by farmers, government programs, from the highlands of Tigray Region. and civil society, synthesizing the evidence In highland Tigray, exclosures on options with the highest potential or increased ecosystem C stocks by 30-60 t ha- feasibility for impact over large areas of 1 (70-130% gains), largely due to soil C Ethiopia. accretion (Mekuria et al. 2011a), sequestering 23 t C ha-1 yr-1 in the first 5 Grazing exclosures years and 11 t C ha-1 yr-1 over 15 years, and Option. Grazing exclosures are also substantially increased soil N and P created to improve year-round availability stocks (Mekuria et al. 2011c). of forage, as well as to protect degraded Consequently, the net present value (NPV) 2 of ecosystem services provided by exclosures remained virtually absent from exclosures (grass production, C the traditionally pastoral lowlands of East sequestration, buildup of soil N and P Shewa in the Rift Valley of Oromia Region, stocks) was estimated to be 28% (USD837) as compared to the 10-60% of available higher than alternative wheat production land in exclosure in 3 districts of highland (Mekuria et al. 2011c). However, Tigray (Nedessa et al. 2005, ecosystem services from older grass- Descheemaeker et al. 2009). dominated exclosures have not been Context. The history of serit local rigorously assessed, yet could yield greater by-laws (Nedessa et al. 2005) and rainy net benefits if synergy exists between season grazing restrictions in Tigray were forage production and C sequestration, or significant precursors for the current use of fewer net benefits if a trade-off prevails. exclosures, as was the decades-long history Over 75% of highland farmers ranked of zero-grazing exclosures in Hararghe effectiveness of exclosures for land (Gebreyohannes and Hailemariam 2011). In restoration as high (52%) or medium (23%) areas such as East Shewa that lack such a with the remainder unsatisfied with history, some old top-down, government extensive regeneration of less-preferable reserves remain, but exclosures have not Acacia spp. (Mekuria et al. 2011c). caught on (Nedessa et al. 2005). Exclosures receive strong support from The biophysical or ecological most communities and the Tigray regional context of an area affects the success of government (Nedessa et al. 2005). exclosures. Older exclosures provide In the well-studied Degua Temben greater environmental benefits, but may not district of highland Tigray, exclosures had give the highest net livelihood benefits. In higher production and standing crop of leaf highland Tigray, litter production and litter (Descheemaeker et al. 2006a), greater standing crop increase with exclosure age sediment depth and deposition rate (Descheemaeker et al. 2006a), and soils in (Descheemaeker et al. 2006c), and older exclosures have more advanced enhanced humus formation humus formation (Descheemaeker et al. (Descheemaeker et al. 2009). Exclosures 2006c). Effects of exclosures on soils are shed only 25-50% as much precipitation in strongest in the first 5 years and soil fertility runoff as compared to open grazing areas did not differ between 5- and 15-year-old (Descheemaeker et al. 2006b), reduced soil exclosures (Mekuria et al. 2007, Mekuria erosion by ~50% (over and above pre- and Aynekulu 2011) although soil C, N, existing stone conservation structures), and P increased significantly between 5 and increased SOM by ~50% (to over 2%), and 20 years (Mekuria et al. 2011a) in highland increased N and P stocks (Mekuria et al. sites. In lowland Tigray, soil C, N, and P 2007). Both farmers and extension officers increased between 5 and 15 years of reported higher yields in croplands below exclosure (Mekuria 2013). exclosures (Mekuria et al. 2009). In both highland and lowland In more arid locations, exclosures Tigray, older exclosures typically produce have been less successful, though they are a less forage due to woody competition, reasonable option in many cases. In the indicating a clear trade-off with wood drier, hotter lowlands of Tigray, gains were production (Mekuria et al. 2011b, 2011c). If less impressive than in the highlands. forage production exhibits a trade-off with Ecosystem C stocks increased by 18-40 t C sequestration as well, C finance could be ha-1 (60-100% gains), again largely due to less feasible than reports indicate. increased soil C, sequestering 3.6 t C ha-1 Moreover, livelihood benefits can be yr-1 in the first 5 years and 2.7 t C ha-1 yr-1 greater from exclosures with more ground over 15 years, and increased soil N and P cover and fewer shrubs and trees that stocks (Mekuria et al. 2011b). By 2004, compete with forage grasses, as well as 3 from exclosures with a faster rate of (Yami et al. 2011). Other significant recovery—those in more productive sites, constraints arise from community with pre-existing soil conservation expectations of high or rapid benefits measures, and enrichment planting (Nedessa et al. 2005, Yami et al. 2013), the (Nedessa et al. 2005, Yami et al. 2013). labor requirements and possible gender Exclosure management depends on implications of exclosures, for zero-grazing the existence and design of local by-laws most particularly (Nedessa et al. 2005), land and institutional mechanisms for tenure arrangements, and the currently rapid enforcement (Nedessa et al. 2005, Yami et individualization of communal lands al. 2011, 2013). Exclosure success is (Nedessa et al. 2005, Yami et al. 2011). generally improved by posting guards to Synthesis. Climate and soils play enforce fines for breaking by-laws, and by key roles in determining the rate of linking village institutions to the vegetation recovery and the potential of government legal system (Yami et al. exclosures to produce benefits within an 2013). However, there is no clear or direct acceptable timeframe, which is strongly relation between exclosure success and the linked to their ultimate success. Exclosures stringency of punishments. Low fines are are less successful and often not feasible in often ignored, but high fines might weaken drier, hotter, lowland areas (where small enforcement (Yami et al. 2011). Regardless, ruminants dominate), unless water