Southern Ethiopian Highlands Research Articles

Landscapes of Memory and Power: The Archaeology of a Forgotten Kingdom in Ethiopia

Unlike their northern counterparts, the kingdoms of southern Ethiopia have received little attention by archaeologists. Their relatively late emergence and absence of literacy may explain this lack of interest. However, they have much to offer to better understand the history not only of the Horn but also of the precolonial African state more generally. In this paper, the polities that developed in the southern Ethiopian highlands during the second millennium AD are briefly described and then one of them is explored in more detail: the kingdom of Anfillo. An archaeological and historical overview of the polity is provided based on two seasons of fieldwork. It is argued that in Anfillo, as in other southern Ethiopian polities, a fortified landscape materialized at the same time a persistent situation of conflict and the collective memory of the ruling classes, which used it as a mnemonic device to tell history and legitimize social divisions.

Analysis of farmers’ perceptions of bench terracing innovation in the eastern and southern Ethiopian highlands

Analysis of farmers’ perceptions of bench terracing innovation in the eastern and southern Ethiopian highlands

Enset landrace diversity in major enset growing regions of Southern Ethiopia

Enset [Ensete ventricosum (Welw.) Cheesman] is an important food security crop of the Southern Ethiopian highlands. The cultivation of enset is characterised by a wide variety of landraces, suitable to varying agro-ecological conditions and with multiple uses by households. The objective of this paper is to present enset landrace diversity, characteristics and uses in Ethiopia. The study was done through interviews with 375 households covering 20 communities (kebeles) and eight ethnic groups, along an altitudinal range of 1,500 to 3,000 masl across the main enset-producing belt in Southern Ethiopia. A total of 296 locally named enset landraces were recorded. Landrace presence was mostly constrained at the kebele and zone levels, with limited overlap in landrace names across these boundaries. Moderate to high enset landrace diversity was observed on farms across the entire study region. Cultivating a variety of landraces not only allowed for diversified uses, but increases the likelihood of retained yield and food security under variable environmental circumstances. Farmer experience and indigenous knowledge allow for the selection of specific landraces suited to prevalent agro-ecological conditions. We identified a perception bias in the attribution of landrace agro-ecological characteristics, with farmer insight often dependent on the environmental conditions that the local community was exposed to. We underscore the importance of research-based characterisation of enset landraces, to ensure optimal cultivation of this food security crop in changing climatic conditions.

Measure of indigenous perennial staple crop, Ensete ventricosum, associated with positive food security outcomes in southern Ethiopian highlands

Enset-based food systems are unique to southern Ethiopia where they serve as a staple food for millions of households. Enset, a banana relative of which the entire pseudostem and corm are edible, possesses a highly unusual combination of crop traits including perenniality, highly flexible planting and harvest times, and tolerance of a very wide range of environmental conditions, which together earn it the local name of “the tree against hunger.” Previous studies have identified the strategic food security value of mature enset stands for household food security, but a multisector panel data set makes identifying wider enset food security associations tractable for the first time. We assess whether household data on area of mature enset is associated with four indicators of food security together with demographic, asset, and consumption covariates. We find that area of mature enset significantly improves estimates for three of four food security indicators, thus improving our understanding of the role of understudied indigenous crops. Consistent and reliable food security indicators are needed to improve monitoring, particularly with regard to stability. Variance components of multilevel longitudinal models indicate that exposure to both idiosyncratic and covariate disturbance affects food security stability in a way that is consistent with reports of enset acting as both a food security buffer and an active adaptation strategy in the face of shocks or change. Here we show that living assets comprising culturally relevant indigenous crops such as enset can improve accuracy of food insecurity assessments, which may encourage wider investigation of other agrifood system-specific asset-like natural stores of value associated with food security and resilience.

Enset Production System Diversity across the Southern Ethiopian Highlands

Enset is a staple crop of the southern Ethiopian highlands. Small-holder farmers cultivate enset as part of mixed subsistence farming systems, in which enset provides substantial food security services. While its cultivation is unique to this region, enset production systems take on many forms, varying with environmental and agronomic conditions, crop diversity and (co-)staples produced, the importance of enset for the household, and socio-economic and cultural differences. Through extensive interviews with 375 households covering 20 communities, along an altitudinal range of 1500 to 3000 masl across the main enset-producing belt, the diversity in enset production systems was assessed. We show that the size of enset-producing land holdings and the overall cultivated farmland decreased with altitude. The economic status of households however drives the proportion of land allocated to enset, with relatively more land (45%) allocated to the cultivation of enset in poorer households compared to medium (38%) and to richer (23%) households. The food crop diversity, with an average of 6.4 different food crop species on a farm (ranging from 2 to 15 crops), did not vary with the wealth status of the households or with altitude. Enset-derived food items were a main component of multiple daily meals for most households, complemented with other crops produced on the farm. Supplemental food purchases mainly included meat and bread products, although the purchasing power of enset-growing households is predominantly low. The co-staples grown varied with altitude, according to crop productive cultivation boundaries. Maize was an important co-staple observed across the entire investigated altitudinal range. At the mid to upper altitudes, wheat and barley often supplemented or substituted maize as the main cereal crop, while at the mid to lower altitudes, teff was produced in addition to maize. Coffee was the main cash crop grown up to altitudes of 2300 m. Root and tuber crops, and legumes had a more moderate importance in these systems. At lower altitudes, yam, sweet potato and taro were the main roots and tubers produced, which shifted to Irish potatoes at the mid to high altitudes. The importance of beans was higher in several high-altitude kebeles. The food crop diversity, combined with livestock rearing are key for the self-reliance of the small-holder subsistence farms. The need for increased enset cultivation was highlighted by the farmers to ensure food availability and food security with population growth. On the other hand, enset cultivation was mainly threatened by Xanthomonas wilt.

English

Xanthomonas wilt of enset is a major bacterial disease affecting the entire enset-growing belt in the southern Ethiopian highlands, impacting food security and livelihoods of small-holder subsistence farmers. Through extensive interviews and field validation visits with 354 households covering 19 communities (kebeles), we show 70% of the farms to present current and past enset Xanthomonas wilt infections, with a median of 18% cumulative plant loss across affected years since disease appearance. Training by extension services proved critical for building up farmers’ knowledge on disease management, the effective implementation of disease management, and farmers’ persistence to continue with enset production even when dealing with widespread infestations. After receiving training, farmers were ten times more likely to implement targeted hygienic practices and only half as likely to implement non-recommended cultural practices. Nevertheless, training in disease management did not guarantee consistent implementation by farmers. Farmers remained reluctant to dispose of infected plants, a critical part of Xanthomonas wilt management. Moreover, farmers mostly applied disease management practices once infected plants are observed on the farm, but were unaware of preventive approaches. Extension services had also not reached all communities, with 64% of the households not having received training at the time of the survey. Key words: Disease management, Ethiopian highlands, farmer training, household surveys, Xanthomonas campestris pv. musacearum

English

Xanthomonas wilt of enset is a major bacterial disease affecting the entire enset-growing belt in the southern Ethiopian highlands, impacting food security and livelihoods of small-holder subsistence farmers. Through extensive interviews and field validation visits with 354 households covering 19 communities (kebeles), we show 70% of the farms to present current and past enset Xanthomonas wilt infections, with a median of 18% cumulative plant loss across affected years since disease appearance. Training by extension services proved critical for building up farmers’ knowledge on disease management, the effective implementation of disease management, and farmers’ persistence to continue with enset production even when dealing with widespread infestations. After receiving training, farmers were ten times more likely to implement targeted hygienic practices and only half as likely to implement non-recommended cultural practices. Nevertheless, training in disease management did not guarantee consistent implementation by farmers. Farmers remained reluctant to dispose of infected plants, a critical part of Xanthomonas wilt management. Moreover, farmers mostly applied disease management practices once infected plants are observed on the farm, but were unaware of preventive approaches. Extension services had also not reached all communities, with 64% of the households not having received training at the time of the survey. Key words: Disease management, Ethiopian highlands, farmer training, household surveys, Xanthomonas campestris pv. musacearum

An hourly ground temperature dataset for 16 high-elevation sites (3493–4377 m a.s.l.) in the Bale Mountains, Ethiopia (2017–2020)

Abstract. Tropical mountains and highlands in Africa are under pressure because of anthropogenic climate and land-use change. To determine the impacts on the afro-alpine environment and to assess the potential socio-economic consequences, the monitoring of essential climate and environmental variables at high elevation is fundamental. However, long-term temperature observations on the African continent above 3000 m are very rare. Here we present a consistent multiannual dataset of hourly ground temperatures for the Bale Mountains in the southern Ethiopian Highlands, which comprise Africa's largest tropical alpine area. The dataset covers the period from January 2017 to January 2020. To characterise and continuously monitor the mountain climate and ecosystem of the Bale Mountains along an elevation gradient from 3493 to 4377 m, ground temperature data loggers have been installed at seven sites at 2 cm depth; at four sites at 10 cm depth; and at five sites at 2, 10, and 50 cm depth. The statistical analysis of the generated time series reveals that ground temperatures in the Bale Mountains are subject to large daily fluctuations of up to 40 ∘C and minor seasonal variations on the order of 5 to 10 ∘C. Besides incoming short-wave radiation, ground moisture, and clouds at night, slope orientation and the type of vegetation coverage seem to be the main factors controlling daily and seasonal ground temperature variations. On the central Sanetti Plateau above 3800–4000 m, the mean annual ground temperature ranges from 9 to 11 ∘C. However, nocturnal ground frost down to a depth of 5 cm occurs frequently during the dry season from November to February. At the five sites where ground temperature is measured at three depths, the monitoring will be continued to trace long-term changes. To promote the further use of the ground temperature dataset by the wider research community dealing with the climate and geo-ecology of tropical mountains in eastern Africa, it is made freely available via the open-access repository Zenodo: https://doi.org/10.5281/zenodo.6047457 (Groos et al., 2022).

The value of flagship and umbrella species for restoration and sustainable development: Bale monkeys and bamboo forest in Ethiopia

Forest loss and degradation are the most significant threats to terrestrial biodiversity in the tropics. Promoting flagship or umbrella species is a strategy that can be used to conserve intact forests and restore degraded ecosystems, conserve biodiversity, and achieve sustainable development goals. The Bale monkey (Chlorocebus djamdjamensis) is an arboreal, forest-dwelling, threatened primate restricted to a small range in the southern Ethiopian Highlands, which relies mostly on a single species of bamboo (Arundinaria alpina) and prefers bamboo forest habitat. Most of the Bale monkey’s range lies outside protected areas and most of its historical bamboo forest habitat is degraded or destroyed. The conservation of Bale monkeys and bamboo is highly inter-dependent; however, the value of using the Bale monkey as a flagship or umbrella species for forest restoration has not been evaluated. Here we use geographic range overlap and geospatial modeling to evaluate Bale monkeys as a flagship and/or umbrella species. We also assess if conservation intervention on behalf of Bale monkeys can help restore bamboo forest, while simultaneously providing a wide range of socioeconomic and environmental benefits. We found that Bale monkeys share their range with 52 endemic and/or threatened vertebrate species and at least 9 endemic and/or threatened plant species. Our results show that Bale monkeys meet both the flagship and umbrella species criteria to restore bamboo forest and conserve threatened co-occurring species. Since bamboo is fast-growing and can be harvested every year, we suggest that a science-based sustainable harvest and management regime for bamboo would help to improve the livelihood of both the local community and Ethiopians in general without significantly affecting the long-term survival of Bale monkeys and regional biodiversity. Further, a conservation management strategy protecting and restoring bamboo forest has the potential to achieve at least six of the 17 United Nations Sustainable Development Goals.

Sleeping Site and Tree Selection by Bale Monkeys (Chlorocebus djamdjamensis) at Kokosa Forest Fragment in Southern Ethiopia

Although selecting advantageous sleeping sites is crucial for nonhuman primates, the extent to which different factors contribute to their selection remains largely unknown for many species. We investigated hypotheses relating to predator avoidance, food access, and thermoregulation to explain the sleeping behavior of Bale monkeys (Chlorocebus djamdjamensis) occupying a degraded fragmented forest, Kokosa, in the southern Ethiopian Highlands. We found that the study group reused 11 out of 20 sleeping sites used during the 42 study days over a 6-month period. Sleeping sites were usually close to the last feeding trees of the day (mean distance =15.2 m) and/or the first feeding trees of the next morning (mean distance = 13.5 m). This may reflect an attempt to maximize feeding efficiency and reduce travel costs. Compared to the mean trees in the study area, sleeping trees were significantly shorter. Bale monkeys selected sleeping places in trees with high foliage density above and below them, lending support to the hypothesis that they select sleeping places that can conceal them from predators and at the same time offer shelter from cold weather. The monkeys also frequently huddled at night. Our results suggest that predator avoidance, access to food resources, and thermoregulation all likely influence the selection of sleeping sites by Bale monkeys.

The enigma of relict large sorted stone stripes in the tropical Ethiopian Highlands

Abstract. Large forms of sorted patterned ground belong to the most prominent geomorphic features of periglacial and permafrost environments of the mid-latitudes and polar regions, but they were hitherto unknown in the tropics. Here, we report on relict large sorted stone stripes (up to 1000 m long, 15 m wide, and 2 m deep) on the ca. 4000 m high central Sanetti Plateau of the tropical Bale Mountains in the southern Ethiopian Highlands. These geomorphic features are enigmatic since forms of patterned ground exceeding several metres are commonly associated with distinct seasonal ground temperatures, oscillating around 0 ∘C. To systematically investigate present frost phenomena and relict periglacial landforms in the Bale Mountains, we conducted extensive geomorphological mapping. The sorted stone stripes were studied in more detail by applying aerial photogrammetry, ground-penetrating radar measurements, and 36Cl surface exposure dating. In addition, we installed ground temperature data loggers between 3877 and 4377 m to analyse present frost occurrence and seasonal ground temperature variations. Superficial nocturnal ground frost was measured at 35–90 d per year, but the ground beneath the upper few centimetres remains unfrozen the entire year. Seasonal frost occurrence would require a mean annual ground temperature depression of about 11 ∘C, corresponding to an air temperature decrease of about 6–8 ∘C (relative to today) as inferred from a simple statistical ground temperature model experiment. Our results suggest the formation of the large sorted stone stripes under past periglacial conditions related to lateral and vertical frost sorting in the course of cyclic freezing and thawing of the ground. It is likely that the stone stripes formed either in proximity to a former ice cap on the Sanetti Plateau over the last glacial period due to seasonal frost heave and sorting or they developed over multiple cold phases during the Pleistocene. Although certain aspects of the genesis of the large sorted stone stripes remain unresolved, the presence of these geomorphic features provides independent evidence besides glacial landforms for unprecedented palaeoclimatic and palaeoenvironmental changes in the tropical Bale Mountains during the (Late) Pleistocene.

Feeding Ecology of the Omo River Guereza (Colobus guereza guereza) in Habitats with Varying Levels of Fragmentation and Disturbance in the Southern Ethiopian Highlands

Dietary responses to the habitat heterogeneity resulting from anthropogenic disturbance vary among primates. Some species alter their foraging strategy and continue to thrive in human-modified habitats while others are unable to modify their diets sufficiently to cope with such disturbance. Over a 12-mo period, we investigated the feeding ecology of the Omo River guereza (Colobus guereza guereza), a subspecies of black-and-white colobus monkeys endemic to Ethiopia, in a large continuous forest (Munessa: LC group), a smaller modified continuous forest (Wondo Genet: SC group), and a tiny forest fragment (Aregash: F group). We found that the forest fragment had higher tree stem densities but lower overall tree basal area than the continuous forests. In all three forests, guerezas were mostly folivorous (LC group: 83%; SC group: 65%; F group: 62%) and consumed young leaves in accordance with their availability. However, in addition to these broad dietary similarities, there were several differences between forests suggesting strategies guerezas may use to cope with habitat heterogeneity in southern Ethiopia. We found that guerezas in anthropogenically altered forests relied less on mature leaves and more on whole fruits (F group) or flowers (SC group) than guerezas in large continuous forest (LC group). Guerezas also devoted large percentages of their feeding time to exotic species in disturbed forests (SC group: 49.0%; F group: 20.6%) but not in the large continuous forest (LC group: 0.0%). Lastly, guerezas in disturbed forests had richer diets (F group, N = 37 species, SC group, N = 32) than those in the large continuous forest (LC group, N = 27). Thus, our study found that within the folivorous dietary strategy of guerezas, there is considerable dietary variability among even neighboring populations experiencing different degrees of habitat fragmentation and degradation. This dietary flexibility may explain the relatively high tolerance of guerezas to human disturbance across their geographic distribution.

Use of cultivated foods and matrix habitat by Bale monkeys in forest fragments: Assessing local human attitudes and perceptions.

Primates inhabiting human-modified landscapes often exploit matrix habitat to supplement their diet with cultivated foods, at times resulting in economic losses and conflict with local people. Understanding human-nonhuman primate interactions and the attitudes and perceptions of local people towards crop feeding species are crucial to designing effective species-based management plans. Over a 12-month period, we used scan sampling to study the consumption of cultivated foods and matrix use patterns by two habituated groups of Bale monkeys (Chlorocebus djamdjamensis), Ethiopian-endemic bamboo specialists, in two forest fragments (Kokosa and Afursa) set amidst human settlements and farmland in the southern Ethiopian Highlands. Further, we conducted interviews with local people to document their attitudes and perceptions towards Bale monkeys at the two sites. We found that Bale monkeys at Kokosa, a more degraded habitat by most measures, consumed significantly more cultivated foods than their counterparts at Afursa. Moreover, Bale monkeys at Kokosa spent significantly more time in the matrix than in the forest habitat, while monkeys at Afursa spent significantly less time in the matrix than in the forest habitat. Not surprisingly, local people displayed a more negative attitude towards monkeys inhabiting Kokosa than those inhabiting Afursa. The differences in Bale monkey cultivated food consumption and matrix use patterns-as well as in local people's attitudes and perceptions towards Bale monkeys-between Kokosa and Afursa are probably associated with differences in habitat structure, degree of habitat alteration, and land-use practices between the sites. We conclude that to ensure long-term coexistence between Bale monkeys and local people in human-modified landscapes, it is vital to incorporate nearby matrix habitats into management plans and to work closely with local communities to develop effective nonlethal crop protection strategies, thereby reducing the likelihood of negative interactions between Bale monkeys and humans.

Population genetic structure and evolutionary history of Bale monkeys (Chlorocebus djamdjamensis) in the southern Ethiopian Highlands

BackgroundSpecies with a restricted geographic distribution, and highly specialized habitat and dietary requirements, are particularly vulnerable to extinction. The Bale monkey (Chlorocebus djamdjamensis) is a little-known arboreal, bamboo-specialist primate endemic to the southern Ethiopian Highlands. While most Bale monkeys inhabit montane forests dominated by bamboo, some occupy forest fragments where bamboo is much less abundant. We used mitochondrial DNA (mtDNA) sequences to analyse the genetic structure and evolutionary history of Bale monkeys covering the majority of their remaining distribution range. We analysed 119 faecal samples from their two main habitats, continuous forest (CF) and fragmented forests (FF), and sequenced 735 bp of the hypervariable region I (HVI) of the control region. We added 12 orthologous sequences from congeneric vervets (C. pygerythrus) and grivets (C. aethiops) as well as animals identified as hybrids, previously collected in southern Ethiopia.ResultsWe found strong genetic differentiation (with no shared mtDNA haplotypes) between Bale monkey populations from CF and FF. Phylogenetic analyses revealed two distinct and highly diverged clades: a Bale monkey clade containing only Bale monkeys from CF and a green monkey clade where Bale monkeys from FF cluster with grivets and vervets. Analyses of demographic history revealed that Bale monkey populations (CF and FF) have had stable population sizes over an extended period, but have all recently experienced population declines.ConclusionsThe pronounced genetic structure and deep mtDNA divergence between Bale monkey populations inhabiting CF and FF are likely to be the results of hybridization and introgression of the FF population with parapatric Chlorocebus species, in contrast to the CF population, which was most likely not impacted by hybridization. Hybridization in the FF population was probably enhanced by an alteration of the bamboo forest habitat towards a more open woodland habitat, which enabled the parapatric Chlorocebus species to invade the Bale monkey's range and introgress the FF population. We therefore propose that the CF and FF Bale monkey populations should be managed as separate units when developing conservation strategies for this threatened species.

Dietary flexibility of Bale monkeys (Chlorocebus djamdjamensis) in southern Ethiopia: effects of habitat degradation and life in fragments

BackgroundUnderstanding the effects of habitat modification on the feeding strategies of threatened species is essential to designing effective conservation management plans. Bale monkeys (Chlorocebus djamdjamensis) are endemic to the rapidly shrinking montane forests of the southern Ethiopian Highlands. Most populations inhabit continuous bamboo forest subsisting largely on the young leaves and shoots of a single species of bamboo. Because of habitat disturbance in recent decades, however, there are now also several dozen small populations inhabiting isolated forest fragments where bamboo has been degraded. During 12-months, we assessed Bale monkey responses to habitat degradation by comparing habitat composition, phenological patterns, and feeding ecology in a largely undisturbed continuous forest (Continuous groups A and B) and in two fragments (Patchy and Hilltop groups).ResultsWe found that habitat quality and food availability were much lower in fragments than in continuous forest. In response to the relative scarcity of bamboo in fragments, Bale monkeys spent significantly less time feeding on the young leaves and shoots of bamboo and significantly more time feeding on non-bamboo young leaves, fruits, seeds, stems, petioles, and insects in fragments than in continuous forest. Groups in fragments also broadened their diets to incorporate many more plant species (Patchy: ≥ 47 and Hilltop: ≥ 35 species)—including several forbs, graminoids and cultivated crops—than groups in continuous forest (Continuous A: 12 and Continuous B: 8 species). Nevertheless, bamboo was still the top food species for Patchy group (30% of diet) as well as for both continuous forest groups (mean = 81%). However, in Hilltop group, for which bamboo was especially scarce, Bothriochloa radicans (Poaceae), a grass, was the top dietary species (15% of diet) and bamboo ranked 10th (2%).ConclusionsWe demonstrate that Bale monkeys are more dietarily flexible than previously thought and able to cope with some degradation of their primary bamboo forest habitat. However, crop raiding and other terrestrial foraging habits more common among fragment groups may place them at greater risk of hunting by humans. Thus, longitudinal monitoring is necessary to evaluate the long-term viability of Bale monkey populations in fragmented habitats.

Diet and activity patterns of Arsi geladas in low-elevation disturbed habitat south of the Rift Valley at Indetu, Ethiopia.

Understanding the basic natural history of threatened primate taxa is crucial to developing and implementing successful conservation strategies for them. Data on feeding ecology and activity patterns are particularly important for identifying the strategies through which primates invest time and foraging effort towards survival and reproduction at a given locale. Here, we report the results of the first study of the diet and activity budget of Arsi geladas, a population of <1000 individuals endemic to a heavily disturbed region of the southern Ethiopian Highlands and believed to represent a new taxon of geladas. We conducted our research on a band of 34 individuals belonging to five, one-male units at Indetu, eastern Arsi, Ethiopia, from August 2010 to May 2011 (excluding March 2011). Feeding accounted for 41.7% of total scans, followed by moving (20.3%), resting (19.0%), and social behavior (19.0%). Feeding and moving increased and resting and socializing decreased during the dry season when food availability was probably lower than during the wet season. Geladas ate mostly graminoid leaves (51.7% of feeding scans) though they also consumed graminoid rhizomes (24.4%), forb tubers (7.1%), forb leaves (7.1%), cactus, shrub, and tree fruits (3.6%), graminoid corms (1.7%), forb roots (1.6%), and unidentified items (3.0%). Underground foods (corms, rhizomes, roots, and tubers) accounted for 22-47% (mean=35%) of the monthly (n=9) diet and were eaten slightly more during the wet season than during the dry season. Contributions of human crops to the gelada diet could not be quantified without creating conflict between farmers and researchers, though we did note that geladas visited farms on 5-10% of study days. Threats from farmers, children, and dogs limited the geladas' access to crops once they entered the farms. Further research involving questionnaire surveys of farmers, direct observation of crop damage by geladas, and DNA metabarcoding of gelada feces are crucial to the development of strategies to mitigate human-gelada conflict in the densely populated Arsi Zone of Ethiopia.

Impacts of habitat loss and fragmentation on the activity budget, ranging ecology and habitat use of Bale monkeys (Chlorocebus djamdjamensis) in the southern Ethiopian Highlands

Understanding the extent to which primates in forest fragments can adjust behaviorally and ecologically to changes caused by deforestation is essential to designing conservation management plans. During a 12-month period, we studied the effects of habitat loss and degradation on the Ethiopian endemic, bamboo specialist, Bale monkey (Chlorocebus djamdjamensis) by comparing its habitat quality, activity budget, ranging ecology and habitat use in continuous forest and two fragments. We found that habitat loss and fragmentation resulted in major differences in vegetation composition and structure between forest types. We also found that Bale monkeys in continuous forest spent more time feeding and traveling and less time resting and socializing than monkeys in fragments. Bale monkeys in continuous forest also had higher movement rates (m/hr) than monkeys in fragments. Bale monkeys in continuous forest used exclusively bamboo and mixed bamboo forest habitats while conspecifics in fragments used a greater variety of habitats including human use areas (i.e., matrix). Our findings suggest that Bale monkeys in fragments use an energy minimization strategy to cope with the lower availability of the species' primary food species, bamboo (Arundinaria alpina). We contend that Bale monkeys may retain some of the ancestral ecological flexibility assumed to be characteristic of the genus Chlorocebus, within which all extant species except Bale monkeys are regarded as ecological generalists. Our results suggest that, like other bamboo eating primates (e.g., the bamboo lemurs of Madagascar), Bale monkeys can cope with a certain threshold of habitat destruction. However, the long-term conservation prospects for Bale monkeys in fragments remain unclear and will require further monitoring to be properly evaluated.

Newly Discovered Bale Monkey Populations in Forest Fragments in Southern Ethiopia: Evidence of Crop Raiding, Hybridization With Grivets, and Other Conservation Threats

Until recently, the Bale monkey (Chlorocebus djamdjamensis), an arboreal primate endemic to the southern Ethiopian highlands, remained virtually unstudied, and its distribution pattern inadequately documented. To broaden our knowledge of the species' distribution and abundance, we carried out interviews with local people and total count surveys for Bale monkeys across 67 fragmented forest sites in human-dominated landscapes in the Oromia and Southern Nations, Nationalities, and People's Regions, Ethiopia. From January 2010 to May 2011, we discovered 26 new Bale monkey populations inhabiting forest fragments at elevations ranging from 2,355 to 3,204 m asl. Across these populations, we recorded 37 groups ranging in size from 9 to 29 individuals (Mean = 19.5, SD = 4.5), for a total of 722 individuals. Black-and-white colobus monkeys (Colobus guereza) were sympatric with Bale monkeys at all sites, while grivet monkeys (Chlorocebus aethiops) were found only at sites where Bale monkeys did not occur. All of the newly discovered Bale monkey sites once contained bamboo forest, though at 35% of the sites bamboo forest had been eliminated during the past two decades. The persistence of Bale monkeys at fragmented sites lacking bamboo suggests greater habitat flexibility for the species than previously thought, though the long-term viability of populations both with and without bamboo remains uncertain. Human hunting in response to crop raiding, a behavior the monkeys engaged in at all sites, represents a major threat facing the newly discovered Bale monkey populations. Furthermore, despite their current lack of sympatry, apparently hybrid individuals between Bale monkeys and grivets were noted at three sites, posing yet another potential obstacle to Bale monkey conservation. Community conservation programs aimed at (1) protecting remaining habitat fragments, (2) planting bamboo and trees within and between fragments, and (3) reducing crop raiding represent the only hope for survival of the newly discovered Bale monkey populations.

Browser selectivity alters post-fire competition between Erica arborea and E. trimera in the sub-alpine heathlands of Ethiopia

Mammalian herbivores have the potential to alter the competitive relations of woody species, if consumption is unevenly distributed between species. At elevations above 3,500 m in the southern Ethiopian highlands, vegetation is dominated by Erica arborea and E. trimera. Both species can potentially grow into short trees, but are burnt on a rotation of 6–10 years, and regenerate by re-sprouting from belowground lignotubers. The regenerating scrub is heavily browsed by cattle. We set up browsing exclosures at three burnt sites to quantify the impact of browsing over a 3-year period. When protected from browsing, E. trimera had similar or better height growth than E. arborea, but in browsed vegetation, E. arborea instead grew taller. Browsing was more intense on E. trimera in the first years after fire, indicating a difference in palatability between the species. We checked if browse quality differed, by analysing shoot contents of acid detergent fibre (ADF), protein, phenolics and tannins. Contrary to expectations, the preferred E. trimera contained more ADF, less protein and had a higher tannin activity than E. arborea. Although the vegetative growth of E. arborea is favoured relative to E. trimera under high browsing pressure, rapid change in abundance would not be expected, since short-interval fire will repeatedly eradicate any gains in vegetative growth. However, within the typical fire return interval of less than 10 years, E. trimera barely reach a reproductive state, whereas E. arborea flower profusely. Under the current regime of fire and browsing, this may in the long run be more important than differences in height growth, leading to a gradual increase in the proportion of E. arborea.

Factors affecting entry and intensity in informal rental land markets in Southern Ethiopian highlands

AbstractInformal land transactions, particularly rental land markets, are emerging in rural Ethiopia in response to the inadequacies of the administratively based land distribution system to meet the growing demand for land and correct imbalances in factor proportions at the farm level. These informal land markets provide a vehicle to equalise factor proportions at the farm level and to improve productivity and hence households' welfare. Among the farmers who lease out land, those who live in the highland‐areas, where land is scarce and unequal, are more likely to engage in these markets. Increases in the size of land holdings relative to labour and livestock ownership, the number of non‐working household members and pressure for subsistence increase the likelihood of leasing out land. On the other hand, increases in the number of working adults, improved nutritional status and greater wealth affect negatively the supply of land into these markets. The potential exists for these markets to improve factor equalisation, reduce inequality in land holdings, and shift the income position of participating households. However, success depends on whether other factor markets are functioning to thwart forced disposal of land to meet subsistence. Public policy has pivotal role in fostering the growth of these markets and their land transfer and factor equalisation functions by ensuring their legally enforceable status, and removing legal restrictions that constrain choices of contracts and trading over greater distances. In addition, both long and short‐term policy measures are needed to reduce the extent to which poor farmers engage in distress transactions.