Kindeya Gebrehiwot

Spotted hyena (Crocuta crocuta) concentrate around urban waste dumps across Tigray, northern Ethiopia

Abstract Context. The spotted hyena (Crocuta crocuta) lives in remarkably close proximity to humans in the degraded and prey-depleted landscapes in Tigray in northern Ethiopia, predominantly feeding on human organic waste. Aims. We sought to provide an estimate of spotted hyena abundance at garbage dumps and open agricultural areas across Tigray. Methods. We used 28 calling stations, including 12 at garbage dumps and 16 in open agricultural areas located in nine randomly selected urban districts across Tigray. We also used 65 randomly placed calling stations in three districts to establish spotted hyena abundance in Tigray. We also collected 610 scat samples during wet (n = 134) and dry season (n = 476) so as to identify diet. Key results. A total of 398 hyenas responded, including 356 hyenas at garbage dumps and 42 hyenas in open agricultural areas. The response at the garbage dumps was significantly higher. Approximately 2525 hyenas were estimated from 65 calling stations in three districts. There was no statistically significant difference in the diet of hyena between wet and dry seasons for any food item. Frequency occurrence of prey remains of donkeys and cattle were dominant, followed by human, goat and sheep, respectively. Key conclusions. We infer that a very large hyena population persists in unprotected areas of Tigray in northern Ethiopia, where they concentrate around urban waste dumps at night for scavengeable food resources, mainly originating from slaughterhouse waste of livestock. Implications. We suggest promotion of nature-based ecotourism of this exceptional coexistence of hyenas and humans in Ethiopia. We raise questions about local hyena social structure, movement, home-range, activity pattern and the implications for human–hyena coexistence.

Regional groundwater flow modeling of the Geba basin, northern Ethiopia

The Geba basin is one of the most food-insecure areas of the Tigray regional state in northern Ethiopia due to recurrent drought resulting from erratic distribution of rainfall. Since the beginning of the 1990s, rain-fed agriculture has been supported through small-scale irrigation schemes mainly by surface-water harvesting, but success has been limited. Hence, use of groundwater for irrigation purposes has gained considerable attention. The main purpose of this study is to assess groundwater resources in the Geba basin by means of a MODFLOW modeling approach. The model is calibrated using observed groundwater levels, yielding a clear insight into the groundwater flow systems and reserves. Results show that none of the hydrogeological formations can be considered as aquifers that can be exploited for large-scale groundwater exploitation. However, aquitards can be identified that can support small-scale groundwater abstraction for irrigation needs in regions that are either designated as groundwater discharge areas or where groundwater levels are shallow and can be tapped by hand-dug wells or shallow boreholes.RésuméLe bassin de Geba est l’une des régions les plus touchées par l’insécurité alimentaire de l’état régional de Tigray dans le nord de l’Ethiopie en raison de sécheresse récurrente résultant d’une répartition erratique des précipitations. Depuis le début des années 1990, l’agriculture pluviale a été soutenue par des projets d’irrigation à petite échelle, principalement par la collecte des eaux de surface, mais le succès a été limité. Par conséquent, l’utilisation des eaux souterraines pour l’irrigation a attiré une attention considérable. Le but principal de cette étude est d’évaluer les ressources en eau souterraine dans le bassin de Geba au moyen d’une modélisation MODFLOW. Le modèle est calibré en utilisant les niveaux d’eau souterraine observés, conduisant à une idée précise concernant les systèmes d’écoulement des eaux souterraines et les réserves. Les résultats montrent qu’aucune des formations hydrogéologiques ne peut être considérées en tant qu’aquifères permettant une exploitation des eaux souterraines à grande échelle. Cependant, des aquitards capables de supporter des prélèvements d’eaux souterraines à petite échelle pour les besoins de l’irrigation peuvent être identifiées soit dans les régions qui sont désignées comme des zones de décharge des eaux souterraines ou des zones où les niveaux d’eau souterraine sont peu profonds et peuvent être captés par des puits creusés à la main ou des forages peu profonds.ResumenLa cuenca de Geba es una de las zonas con mayor inseguridad alimentaria del estado regional de Tigray en el norte de Etiopía debido a las recurrentes sequías resultantes de la distribución irregular de las lluvias. Desde comienzos de los años noventa, la agricultura de secano ha sido apoyada mediante regímenes de riego a pequeña escala, principalmente mediante la recolección de aguas superficiales, pero el éxito ha sido limitado. Por lo tanto, el uso de agua subterránea para fines de riego ha ganado considerable atención. El propósito principal de este estudio es evaluar los recursos de agua subterránea en la cuenca de Geba mediante un enfoque de modelado MODFLOW. El modelo se calibra usando los niveles observados de agua subterránea, lo que da una idea clara de los sistemas de flujo de agua subterránea y reservas. Los resultados muestran que ninguna de las formaciones hidrogeológicas puede ser considerada como acuíferos que pueden explotarse en una explotación de agua subterránea a gran escala. Sin embargo, se pueden identificar acuitardos que pueden apoyar la extracción de agua subterránea a pequeña escala para las necesidades de riego en regiones designadas como áreas de descarga de aguas subterráneas o donde los niveles de aguas subterráneas son superficiales y pueden ser aprovechados por pozos excavados a mano o pozos poco profundos.摘要由于降雨分布极度不均从而造成周期性的干旱,致使Geba流域是埃塞俄比亚北部Tigray州粮食最得不到保障的地区之一。自从20世纪90年代开始,旱作农业主要通过地表水收集而进行的小规模灌溉计划得到支持,但成就有限。因此,使用地下水用于灌溉受到了人们的极大关注。本研究的主要目的就是通过MODFLOW模拟方法评价Geba流域的地下水资源。采用观测的地下水位校正模型,深入了解了地下水流系统和地下水储量。结果显示,没有一个水文地质层可以作为含水层进行大规模地下水的开采。然而,发现一些弱透水层,这些弱透水层在地下水排泄区或地下水位浅的地方可以进行地下水开采以满足灌溉所需,可以通过手工挖掘井或者浅的机井抽取。ResumoA bacia de Geba é uma das áreas de maior insegurança alimentar no estado regional de Tigray, Norte da Etiópia, devido às secas recorrentes resultantes da distribuição errática da precipitação. Desde o inicio da década de 1990, a agricultura dependente da chuva vem sendo mantida por sistemas de irrigação de pequena escala, majoritariamente utilizando águas superficiais, mas o êxito tem sido limitado. Desse modo, a utilização de águas subterrâneas para irrigação ganhou uma atenção considerável. O principal propósito desse estudo é avaliar os recursos hídricos subterrâneos na bacia de Geba por meio de modelagem utilizando o MODFLOW. O modelo é calibrado utilizando níveis freáticos observados, fornecendo uma visão clara sobre o sistema de fluxo e reservas de água subterrânea. Os resultados demonstram que nenhuma das formações hidrogeológicas podem ser consideradas como aquíferos que permitem a extração de água subterrânea em larga escala. Entretanto, podem ser identificados aquitardos que podem apoiar a captação de águas subterrâneas em pequena escala para utilização na irrigação em regiões que são tanto designadas como áreas de descarga como onde os níveis freáticos são rasos e podem ser captados por poços escavados a mão ou poços rasos.

Evolution of land use-change modeling : routes of different schools of knowledge

Although much has been published on land use-change models (LUCMs), no study has comprehensively dealt with the evolution of land use models based on schools of knowledge. The primary objective of this paper is an explanation of the progress and growth of LUCMs concerning their main ontological, epistemological, and methodological origins. Five main paradigms, i.e., positivism, post-positivism, constructivism, participatory, and pragmatism approaches, are discussed in order to assess the current orientations of LUCMs. Given the complexities of LUCM components, the study concludes that one paradigm cannot adequately address all methodological aspects. Accordingly, it is necessary to combine quantitative and qualitative paradigms to create mixed-method approaches within a systemic framework. Such systemic approaches could shape the most probable future generations of LUCMs, which would be able to cope with the complexity of various subsystems, including biophysical and socioeconomic ones.

Food base of the spotted hyena (Crocuta crocuta) in Ethiopia

Abstract Context. Livestock depredation and scavenging of waste by the spotted hyena (Crocuta crocuta) occurs widely across Ethiopia. Aims. The aim of this study was to investigate the food base of the spotted hyena and livestock depredation across Ethiopia. Methods. The diet of spotted hyenas was assessed in 17 randomly selected study sites across the country, including two national parks, by scat analysis. We conducted an extensive survey of livestock depredation and economic impact in 10 randomly selected subdistricts using semistructured interviews with 3080 randomly selected households. Key results. We found that even spotted hyenas from national parks feed predominantly on anthropogenic waste. Households reported losses of 2230 domestic animals, 3.9% of their stock or an average annual financial loss of US

Arbuscular mycorrhiza and water and nutrient supply differently impact seedling performance of dry woodland species with different acquisition strategies

10.3 per household over the past five years. The diet of spotted hyenas showed only prey items of domestic origin except in Chebera Churchura National Park, where a few items of prey of wild species were found. Frequencies of prey remains of cattle, sheep, donkey and goat were highest in decreasing order. Key conclusions. Survival of hyenas in Ethiopia is thus largely and widely dependent on management of livestock conflict and waste. Some hairs in scats originated from depredation, but most food intake is from waste dumps and slaughterhouses. Implications. Waste management, spotted hyena persistence and environmental sanitation area are linked.

Preliminary investigation on rodent-ectoparasite associations in the highlands of Tigray, Northern Ethiopia: implications for potential zoonoses.

Background: Arbuscular mycorrhizal (AM) fungi increase seedling survival and performance through enhancement of nutrient and water uptake under stress conditions. Acacia etbaica, A. senegal and Boswellia papyrifera dominate large areas in African drylands where both moisture and nutrients are limited. Aims: We evaluated the effects of AM, drought and soil quality on carbon gain (growth), gas exchange and nutrient contents of seedlings of these three dry woodland species. Methods: We used a greenhouse experiment with a fully factorial design of two levels of AM, two levels of soil and four levels of water availability, on the carbon gain, gas exchange and nutrient content of seedlings of the three species. Results: AM symbiosis enhanced the acquisition of water and nutrients and increased gas exchange resulting in increased Acacia and Boswellia seedling biomass. The rapidly growing Acacia species (acquisitive strategy) showed larger mycorrhizal benefit at higher water availability. The slow-growing Boswellia (conservative strategy), in contrast, showed larger mycorrhizal benefit at lower water availability. Conclusions: This study showed that different species of dry woodlands benefit from AM in different ways depending on the resource use strategy under stress conditions. The inclusion of the mycorrhizal habit in trait-based approaches increases understanding of functional differences of coexisting tree species.

Reproduction and survival of rodents in crop fields: the effects of rainfall, crop stage and stone-bund density

We studied associations between rodents and their arthropod ectoparasites in crop fields and household compounds in the highlands of Tigray, Northern Ethiopia. Ectoparasite infestation indices, such as percent infestation, mean abundance, prevalence and host preferences, were calculated for each taxon. In total, 172 rodents from crop fields and 97 from household compounds were trapped. Rodent species and numbers trapped from the crop fields and household compounds were Mastomys awashensis (Lavrenchenko, Likhnova & Baskevich, 1998) (88 and 44), Arvicanthis dembeensis (Ruppel, 1842) (63 and 37) and Acomys sp. (21 and 16), respectively. A total of 558 insects and acarids (belonging to 11 taxa) were recovered from the rodents trapped in the crop fields, and 296 insects and acarid (belonging to 6 taxa) from the rodents trapped in the household compounds. Approximately 66% of the rodents trapped from the crop fields and 47% of those trapped from the household compounds were infested with ectoparasites. Laelaps sp. (64.9%) and Xenopsylla sp. (20.6%) comprised the highest proportion of the ectoparasites recovered in the crop fields, and the same ectoparasites, but in reverse order, comprised the highest proportions in the household compounds (Xenopsylla [50.3%] and Laelaps sp. [29%]). Our study revealed that crop fields and household compounds in the highlands share similar rodents and several ectoparasites. Furthermore, at least 1 of the rodent species and some of the ectoparasites identified in this study were reported to have posed medical and veterinary threats in other parts of Ethiopia and neighboring countries.

Original papersEffect of side-wings on draught: The case of Ethiopian ard plough (maresha)

Abstract Context. Reproduction and survival are two of the most important demographic factors that play a major role in changing population abundances of pest species over time and space, solid understanding of which is a useful input to forecast future population changes for proactive management. Aims. We investigated the effects of rainfall, crop-development stage and density of stone bunds on reproductive patterns, and the effects of stone-bund density and sex on survival probabilities of two widespread rodent species (Mastomys awashensis and Arvicanthis dembeensis) in Ethiopian highlands. Methods. Rodent population dynamics were monitored from April 2007 to February 2011, using capture–mark–recapture (CMR) technique in four 60 × 60 m permanent square grids for four consecutive cropping seasons. Two of the grids represented fields with low stone-bund density (LSBD, ∼15 m apart) and the other two represented fields with high stone-bund density (HSBD, ∼10 m apart). Key results. Reproduction was seasonal, commencing during the wet season following the rain and continuing through the early dry season. We found an increase in the abundance of reproductively active female individuals of both species towards the milky and fruiting crop stages and around harvest period. We found no strong difference in survival probability between the two rodent species with variation in stone-bund density and sex. Conclusions. Stone bunds play a minor role in the reproduction and survival of the rodent species at the observed abundances. Implications. In terms of pest management, the high local survival rates estimated for both rodent species matter more than survival differences owing to variations in stone-bund density and sex.

Effect of side-wings on draught

Field soil bin test facility is developed.It measures online tillage force.It helps to investigate effect of maresha geometry on draught requirement. Ethiopian farmers have been using an ox-drawn breaking plough, known as ard plough - maresha, for thousands of years. Maresha is a pointed, steel-tipped tine attached to a draught pole at an adjustable shallow angle. It has narrow side-wings, attached to the left and right side of it, to push soil to either side without inverting.The aim of this paper is to explore the effect of side-wings on draught using a field soil bin test facility. To this end, a mobile and an in-situ soil bin test system, for online measurements of draught, was designed and developed. This research considered tool geometry (maresha plough with and without side-wings) and rake angle (shallow - 8°, medium deep - 15°, and deep - 24°, representing primary, secondary and tertiary tillage processes in Ethiopia, respectively).Maresha plough with side-wings has greater contact area, between the moving soil and tool, than its wingless counterpart. When the ploughshare surface and soil slide relative to one another, the draught expected to increase with contact area, as adhesion and friction resistance increases with area. However, experimental analysis indicated that the maresha with side-wings required less draught compared to maresha without side-wings (ź<0.001). This might be attributed to the effect of side-wings on crack propagation by a wedging effect to enhance and facilitate subsequent ploughing.This paper also dealt with the effect of rake angle on draught. Though the depth setup was getting smaller d1

Effectiveness of exclosures to restore degraded soils as a result of overgrazing in Tigray, Ethiopia

Field soil bin test facility is developed.It measures online tillage force.It helps to investigate effect of maresha geometry on draught requirement. Ethiopian farmers have been using an ox-drawn breaking plough, known as ard plough - maresha, for thousands of years. Maresha is a pointed, steel-tipped tine attached to a draught pole at an adjustable shallow angle. It has narrow side-wings, attached to the left and right side of it, to push soil to either side without inverting.The aim of this paper is to explore the effect of side-wings on draught using a field soil bin test facility. To this end, a mobile and an in-situ soil bin test system, for online measurements of draught, was designed and developed. This research considered tool geometry (maresha plough with and without side-wings) and rake angle (shallow - 8°, medium deep - 15°, and deep - 24°, representing primary, secondary and tertiary tillage processes in Ethiopia, respectively).Maresha plough with side-wings has greater contact area, between the moving soil and tool, than its wingless counterpart. When the ploughshare surface and soil slide relative to one another, the draught expected to increase with contact area, as adhesion and friction resistance increases with area. However, experimental analysis indicated that the maresha with side-wings required less draught compared to maresha without side-wings (ź<0.001). This might be attributed to the effect of side-wings on crack propagation by a wedging effect to enhance and facilitate subsequent ploughing.This paper also dealt with the effect of rake angle on draught. Though the depth setup was getting smaller d1