Sil Lanckriet

A Political Ecology Perspective of Land Degradation in the North Ethiopian Highlands

Severe environmental degradation in the north Ethiopian Highlands is among others the result of mismanagement, overpopulation and droughts. However, here, we investigate the linkages of land degradation with the historical dynamics of the political–ecological system and regional land policies. We performed semi-structured interviews with 93 farmers in eight villages in the Tigray region (north Ethiopia) and conceptualised a political–ecological model of land tenure and degradation changes for the region. Results show that different land policies caused and still cause land degradation in several ways. Interviews reveal that the unequal character of land rights during feudal times played an important role in 19th and 20th century land degradation. In particular, poor farmers were forced to construct their farms on marginal terrains, such as steep slopes in dry areas and marshes in cold and humid areas, increasing the catchment water runoff and degradation. The interviews further suggest that after the Derg regime (1974–1991), environmental conservation strategies were successfully implemented at larger scales. Overall, feudal, Derg and contemporary land policies have all had impacts on environmental degradation and have left their fingerprints on the physical landscape of northern Ethiopia. Copyright

RESTORING CROPLAND PRODUCTIVITY AND PROFITABILITY IN NORTHERN ETHIOPIAN DRYLANDS AFTER NINE YEARS OF RESOURCE-CONSERVING AGRICULTURE

Long-term in situ soil and water conservation experiments are rare in sub-Saharan Africa, particularly in Eastern Africa. A long-termexperiment was conducted (2005–2013) on aVertisol to quantify the impacts of resource-conserving agriculture (RCA) on runoff, soil loss, soil fertility and crop productivity and economic profitability in northern Ethiopia. Two RCA practices were developed from traditional furrow tillage practices: (i) derdero+ (DER+) and terwah+ (TER+). DER+ is a furrow and permanent raised bed planting system, tilled once at planting time by refreshing the furrow and 30% of crop residue is retained. TER+ is ploughed once at planting, furrows are made at 1.5 m intervals and 30% crop residue is retained. The third treatment was a conventional tillage (CT) with a minimum of three tillage operations and complete removal of crop residues. Wheat, teff, barley and grass pea crops were grown in rotation. Runoff, and soil and nutrient loss were measured in plastic sheet-lined collector trenches. Significantly different (P < 0.05) runoff coefficients (%) and soil losses (t ha−1) averaged over 9 yrs were 14 and 3, 22 and 11 and 30 and 17 for DER+, TER+ and CT, respectively. Significant improvements in crop yield and gross margin were observed after a period of three years of cropping This study demonstrated that RCA systems in semi-arid agro-ecosystems constitute a field rainwater conservation and soil fertility improvement strategy that enhances crop productivity and economic profitability. Adoption of RCA systems (DER+ and TER+) in the study area requires further work to improve smallholder farmers’ awareness on benefits, to guarantee high standards during implementation and to design appropriate weed management strategies.

Nonlinear vegetation cover changes in the North Ethiopian Highlands: Evidence from the Lake Ashenge closed basin.

Vegetation cover changes in African drylands are often thought to result from population growth, social factors and aridification. Here we show that long-term vegetation proxy records can help disentangling these main driving factors. Taking the case of North Ethiopia, we performed an integrated investigation of land cover changes over the last four centuries around the endorheic Lake Ashenge, as derived from pollen analysis and repeat photography complemented with information from historical sources. Pollen and sediment analysis of radiocarbon-dated lake deposits shows a phase of environmental destabilization during the 18th century, after a more stable previous period. This is evidenced by decreases of tree pollen (Juniperus, Olea, Celtis, Podocarpus<5%), increases in Poaceae (>40%) and deposition of coarser silt lake sediments (>70%). Quantitative analysis of 30 repeated landscape photographs around the lake indicates a gradual decline of the vegetation cover since a relative maximum during the mid-19th Century. Vegetation cover declined sharply between the 1950s and the 1980s, but has since begun to recover. Overall, the data from around Lake Ashenge reveal a nonlinear pattern of deforestation and forest regrowth with several periods of vegetation cover change over the past four centuries. While there is forcing of regional drought and the regional land tenure system, the cyclic changes do not support a simplified focus on aridification or population growth.

Toward Practical Implementation of Conservation Agriculture: A Case Study in the May Zeg-zeg Catchment (Ethiopia)

Conservation agriculture (CA) is often quoted as a beneficial resource-saving technique for dryland agriculture, but its large-scale implementation is frequently hindered by the lack of farmers’ acceptance. To date, few studies have investigated the impact of spatial factors, costs and benefits and regional agroecosystem differentiation on adoption of CA. This study, therefore, aims to assess the impact of these factors through a case study in the North Ethiopian Highlands. One hundred eight farmers of 11 villages surrounding an experimental plot were interviewed in order to identify their knowledge and acceptance of the technique. The results show that several spatial factors play a role in CA acceptance. The lack of knowledge on the resource-saving technique proved primarily dependent (R = –0.73) on spatial impedance with the innovation source and on the strength of sociospatial networks. Next, a consumer model showed that perceived costs and benefits seem to balance each other. Finally, some agronomic traditions were identified that are related to the regional agroecosystem, which are not favoring the implementation of zero-tillage practices. Since this study identified acceptance problems related to several spatial and regional factors, future CA adoption schemes must allow better regional differentiation optimized to local contexts and conditions.

Land Degradation in the Ethiopian Highlands

The high soil erosion rates in the Ethiopian highlands find their causes in the combination of erosive rains, steep slopes due to the rapid tectonic uplift during the Pliocene and Pleistocene, and human impact by deforestation, overgrazing, agricultural systems where the open field dominates, impoverishment of the farmers, and stagnation of agricultural techniques. Travelling in the Ethiopian highlands, one can see many soil and water conservation structures. Indigenous knowledge and farmers’ initiatives are integrated with these introduced technologies at various degrees. This chapter addresses the status and drivers of land degradation in northern Ethiopia, including changes over the last century.

Nine years of conservation agriculture-based cropping systems research in eastern Africa to soil degradation and mitigate effects of climate change

Interpreting palaeovegetation and contemporary palaeoclimate from fossil pollen requires information on modern pollen-rain or deposition patterns of pollen/ spores in sediments of tropical deciduous forest (moist as well as dry types) in the area of investigation, which is achieved through the pollen analysis of surface samples, viz. surface soils/sediments, moss cushions (moss polsters), mud samples, spider web samples, leaf surface and bark that reflect modern vegetation and could be of immense help to refine and strengthen the interpretation of fossil pollen samples (Wright 1967; Flenley 1973; Moore & Webb 1978; Birks & Birks 1980; Liu & Lam 1985; Fall 1992). In the science of Quaternary palynology, this type of study has been given various names such as modern pollen-rain studies, modern pollen deposition patterns, modern pollenvegetation relationships, etc. In some advanced literature, the study has been given the name of Response Transfer Function as it serves as a modern analogue for the accurate explanation of the pollen sequences generated from the sedimentary beds in terms of past vegetation and climate in chronological order in the region during the Quaternary Period, especially the Holocene and/or Late Pleistocene epochs (Quamar & Chauhan 2012, 2013b; Chauhan & Quamar 2012a, 2012b). So far as the relationship between the present-day set-up of vegetation and pollen assemblages is concerned, it is not straightforward. Owing to the differences in pollen production, dispersal and preservation (of taxa), some plant taxa are overrepresented in pollen records whilst others are either under-represented or not represented at all (Tauber 1965; Prentice 1985; Prentice et al. 1987; Jackson & Lyford 1999; Sugita 2007) which depends on plant species and climatic conditions (Hicks 2001; Spieksma et al. 2003). Anemophilous species producing high quantities of pollen grains are over-represented, whereas species with zoophilous means of pollination produce lower numbers of pollen grains and are underrepresented in pollen assemblages (Faegri & Iverson 1964). In tropical regions, traditional pollen analysis was once upon a time thought to be impossible (Faegri 1966; Flenley 1973; Bush 1995) owing to the towering diversity of the tropical pollen flora (Flenley 1973), which was previously regarded as a stumbling block for palynologists to manage, in addition to the effect of pollen production and dispersal (on pollen analysis). However, credit goes to Flenley (1973) who for the first time investigated the modern pollen rain in the tropics systematically. Many tropical pollen taxa are rarely or never encountered in samples, despite their pollen production and dispersal to sample sites, but with the aid of modern pollen spectra the modern pollen deposition pattern could be successfully related to the vegetation. 3rd International Conference on Biodiversity & Sustainable Energy Development June 24-26, 2014 Valencia, Spain Extended Abstract Journal of Biodiversity & Endangered Species Like most palaeoecological research, the majority of work on modern pollen spectra has been carried out in temperate regions. However, the increasing interest in palaeoecological reconstruction of past tropical environments over the preceding two decades has led to more work on modern pollen spectra. A number of recent studies have been carried out in tropical areas of Africa (Vincens et al. 1997, 2000; El Ghazali & Moore 1998, Elenga et al. 2000), Australia (Kershaw & Stickland 1990; Kershaw & Bulman 1994; Crawley et al. 1994) and the mainland Neotropics (Grabant 1980; Bush 1991; Islebe & Hooghiemstra 1995; Rodgers & Horn 1996; Bush & Rivera 1998; Bush 2000; Bush et al. 2001, Marchant et al. 2001; Weng et al. 2004). In the Carribean islands, a few studies exist of sedimentary pollen profiles from lowland sites (Hodell et al. 1991; Higuera-Gundy et al. 1999), but modern pollen studies are wanting. Modern pollen rain studies were also conducted in Australia (Walker & Sun 2000), Southern Peru (Weng et al. 2004), Dominican Republic (Kennedy at al. 2005), southern Brazil (Behling & Negrelle 2006), tropical Andes (Rull 2006), northern Ecuador (Moscol Olivera et al. 2009), northeast Bolivia (Gosling et al. 2009), southern Ecuadorian Andes (Niemann et al. 2010), northern Belize (Bhattacharya et al. 2011), etc. and had generated data sets on the transfer functions regarding pollen representation to environmental parameters, as well as indicator taxa for particular ecosystems. Haselhorst et al. (2013) also conducted pollen rain studies in Panama and emphasized a better and more accurate reconstruction of palaeoenvironment and palaeoclimate in long-term pollen rain studies. However, in South Asia, especially India and Sri Lanka, Bonnefille et al. (1999), Anupama et al. (2000), Barboni and Bonnefille (2001) have conducted studies to address the modern pollen deposition pattern in tropical evergreen and deciduous forests. From the Indian context, several studies have also been conducted to address the problem, for example, from the foothills of the Himalaya (Sharma 1985; Gupta & Yadav 1992; Chauhan & Sharma 1993; Quamar and Srivastava, 2013; Ranhotra and Bhattacharayya, 2013), Kashmir (Vishnu-Mittre 1966; Vishnu-Mittre & Sharma 1966, VishnuMittre & Robert 1971), Ladakh (Bhattacharyya 1989a), Himachal Pradesh (Sharma 1973; Bhattacharayya 1989b, 1989c; Bera & Gupta 1990), tropical deciduous scrub vegetation in Rajasthan desert (Singh et al. 1973), eastern Madhya Pradesh (Chauhan 1994, 2008; Quamar & Chauhan 2007), southwestern Madhya Pradesh (Quamar & Chauhan 2010, 2011a, 2011b, 2012, 2013a; Chauhan & Quamar 2012a, 2012b), Chhattisgarh (Quamar & Bera 2013a, 2013b, 2013c), Silent Valley, south India (Gupta & Bera 1996), Tamil Nadu (Bera & Gupta 1992), Uttar Pradesh (Sharma et al. 2007; Trivedi & Chauhan 2011)), northeast India (Gupta & Sharma 1985; Bera & Gupta 1992; Bera 2000; Basumatary & Bera 2007, 2010; Dixit & Bera 2011, 2012a, 2012b, 2013; Bera et al. 2012, 2013; Basumatary et al. 2013), South and Little Andaman Islands (Singh et al. 2010) and Odisha (Singh et al. 2011), etc. These studies have provided plausible assessments of the palaeovegetation and contemporary climatic scenarios from their respective regions during the Late Quaternary Period. The present communication, however, reviews the modern pollen rain studies carried out so far from southwestern Madhya Pradesh in India, with a view to refine and strengthen the interpretation of fossil pollen records, allowing the improved resolution of palaeoenvironmental changes (Prentice et al. 1991; Separ et al. 1994). The present study reviews the pattern of modern pollen-rain carried out from south-western Madhya Pradesh, India, which largely revealed Extended Abstract Journal of Biodiversity & Endangered Species 3rd International Conference on Biodiversity & Sustainable Energy Development June 24-26, 2014 Valencia, Spain 1 that Tectona grandis (teak), despite being an enormous pollen producer (7500 average number of absolute pollen/flower) (Bhattacharya et al., 1999) and the dominant forest constituent (80 to 95% of the total forest constituents), is recorded mostly in low frequencies, attributable to its low pollen dispersal efficiency as well as poor pollen preservation in the sediments. However, Madhuca indica (Mahua) and other dominant members of Sapotaceae (cf. Manilkara hexandra and Mimusops elangi) have always shown theirs’ typical behaviour in the pollen spectra and representing in high frequencies, which is assigned to its local abundance around the provenance of the samples, coupled with high dispersal efficiency as well as good pollen preservation in the sediments. Meanwhile, the other usual and characteristic associates of teak (Tectona grandis) in the tropical deciduous forests, despite being the common elements of the forests, are underrepresented, sporadically represented or not represented at all, which could be ascribed to theirs’ low pollen productivity owing to entomogamy. Various factors that affect the deposition pattern of the diverse constituents of the tropical deciduous forests dominated by teak (Tectona grandis) have been discussed and suggestions were also given while interpreting the pollen sequences generated from the sedimentary beds in terms of past vegetation and climate in a chronological order in the region during the Late Quaternary Period. This work is partly presented at 3rd International Conference on Biodiversity & Sustainable Energy Development June 24-26, 2014 Valencia, SpainIn Ethiopia, repeated plowing, complete removal of crop residues at harvest and aftermath grazing of crop fi elds have reduced the biomass return to the soil and aggravated cropland degradation. Conservation Agriculture (CA)-based cropping systems may reduce runoff and soil erosion, and improve soil quality and crop productivity. Thus, a long-term tillage experiment has been carried out (2005 to 20123) on a Vertisol to quantify - among others - changes in runoff and soil loss for two local tillage practices, modifi ed to integrate CA principles in semi-arid northern Ethiopia. The experimental layout was a randomized complete block design with three replications on permanent plots of 5 m by 19 m. The tillage treatments were (i) derdero+ (DER+) with a furrow and permanent raised bed planting system, ploughed only once at planting by refreshing the furrow from 2005 to 2013 and 30% standing crop residue retention, (ii) terwah+ (TER+) with furrows made at 1.5 m interval, plowed once at planting, 30% standing crop residue retention and fresh broad beds, and (iii) conventional tillage (CT) with a minimum of three plain tillage operations and complete removal of crop residues. Wheat, teff, barley and grass pea were grown in rotation. Runoff and soil loss were measured daily. Signifi cantly different (p<0.05) runoff coeffi cients averaged over 9 years were 14, 22 and 30% for DER+, TER+ and CT, respectively. Mean soil losses were 3 t ha-1 y-1 in DER+, 11 in TER+ and 178 in CT. A period of at least three years of cropping was required before improvements in crop yield became signifi cant. Further, modeling of the sediment budgets shows that total soil loss due to sheet and rill erosion in cropland, when CA would be practiced at large scale in a 180 ha catchment, would reduce to 581 t y-1, instead of 1109 t y-1 under the current farmer practice. Using NASA/GISS Model II precipitation projections of IPCC scenario A1FI, CA is estimated to reduce soil loss and runoff and mitigate the effect of increased rainfall due to climate change. For smallholder farmers in semi-arid agro-ecosystems, CA-based systems constitute a fi eld rainwater and soil conservation improvement strategy that enhances crop and economic productivity and reduces siltation of reservoirs, especially under changing climate. Adoption of CA-based systems in the study area requires further work to improve smallholder farmers’ awareness on benefi ts, to guarantee high standards during implementation and to design appropriate weed management strategies.