Geoturism in Africa. the Simien Mountains

The paper is dedicated to the geological structure of Ethiopia and Simien Mountains, which are located in the northern part of the North Ethiopian Plateau composed of Oligocene plateau basalts hosting Oligocene-Miocene shield volcanoes.

Earth Observation-Based Detectability of the Effects of Land Management Programmes to Counter Land Degradation: A Case Study from the Highlands of the Ethiopian Plateau

In Ethiopia land degradation through soil erosion is of major concern. Land degradation mainly results from heavy rainfall events and droughts and is associated with a loss of vegetation and a reduction in soil fertility. To counteract land degradation in Ethiopia, initiatives such as the Sustainable Land Management Programme (SLMP) have been implemented. As vegetation condition is a key indicator of land degradation, this study used satellite remote sensing spatiotemporal trend analysis to examine patterns of vegetation between 2002 and 2018 in degraded land areas and studied the associated climate-related and human-induced factors, potentially through interventions of the SLMP. Due to the heterogeneity of the landscapes of the highlands of the Ethiopian Plateau and the small spatial scale at which human-induced changes take place, this study explored the value of using 30 m resolution Landsat data as the basis for time series analysis. The analysis combined Landsat derived Normalised Difference Vegetation Index (NDVI) data with Climate Hazards group Infrared Precipitation with Stations (CHIRPS) derived rainfall estimates and used Theil-Sen regression, Mann-Kendall trend test and LandTrendr to detect changes in NDVI, rainfall and rain-use efficiency. Ordinary Least Squares (OLS) regression analysis was used to relate changes in vegetation directly to SLMP infrastructure. The key findings of the study are a general trend shift from browning between 2002 and 2010 to greening between 2011 and 2018 along with an overall greening trend between 2002 and 2018. Significant improvements in vegetation condition due to human interventions were found only at a small scale, mainly on degraded hillside locations, along streams or in areas affected by gully erosion. Visual inspections (based on Google Earth) and OLS regression results provide evidence that these can partly be attributed to SLMP interventions. Even from the use of detailed Landsat time series analysis, this study underlines the challenge and limitations to remotely sensed detection of changes in vegetation condition caused by land management interventions aiming at countering land degradation.

The Eastern Desert in the 1st Millennium bce and 1st Millennium ce

This chapter looks at the role played by the Eastern Desert and its inhabitants in the historical processes that affected northeastern Africa in the 1st millennium bce–1st millennium ce. The environmental setting and the factors limiting the present knowledge of the history of the region are outlined. The relevance of the Eastern Desert for the Nile valley regions and, in general, for the ancient world is stressed. The written sources on the region are discussed as well as the available archaeological data. Special emphasis is put on the relations between the inhabitants of the Eastern Desert and those of the Nile valley and on the role they played in the development of states, both in the Nile valley and on the Ethiopian plateau.

Activity Budget and Feeding Ecology of Geladas (Theropithecus gelada obscurus) around Abogedam Church West of Debre Berhan Town, Ethiopia

Geladas are the most distinctive of Ethiopian endemic mammals, representing the last extant species of primate genus that have a very restricted distribution in the northern Ethiopian plateau. The activity budget and feeding ecology of geladas (Theropithecus gelada obscurus) were studied around Abogedam Church, Ethiopia, from May to October 2014, encompassing dry and wet seasons. The scan sampling method was applied to collect behavioural data on the identified band. Activity scans were collected at 15-minute intervals for up to five minutes duration from 0700 to 1730 h. The activity recorded for each individual was the first activity that lasts for five seconds. During each scan, individuals were recorded as performing activities: feeding, moving, resting, playing, aggression, grooming, sexual activity, and others. On average, geladas devoted 57.19% feeding, 14.82% resting, 14.92% moving, 4.83% playing, 2.53% aggression, 4.14% grooming, 1.23% sexual activity, and 0.34% other activities such as vocalization, defecation, and urination. Forty-one plant species were consumed by geladas that belonged to 18 families of which 53.66% were grasses. This study provides basic information on further studies and motivates conservationists to plan the management of unprotected areas at the vicinity of agricultural lands where such endemic animals dwell.

Spatial Analysis of Soil Water Content in Newly Implemented Agricultural Bench Terraces in the Ethiopian Plateau

<p>In arid areas prone to desertification and soil erosion, the effectiveness of agricultural bench terraces in increasing soil moisture is dependent on their correct implementation. However, despite its relevance for securing food production in many areas of the world, the relationship between proper terracing implementation and the landscape capacity of holding soil moisture is still not understood. Moreover, spatial patterns of Soil Water Content (SWC) within the same terraced hillslope are weakly studied. The present work analyses SWC variations in four newly implemented terraced sites in Tigray Region, Ethiopia: Teshi, Ruba Feleg, Michael Emba and Enda Chena. Field SWC data were collected for the dry season of 2017 (February, March and April) from the upper, middle and lower part of each terraced site, including a non-terraced benchmark area. In all sites, terraced areas show SWC significantly higher than non-terraced ones (p < 0.05), with the lower part of the terraced hillslope more humid than the others for the whole period analyzed. A Multiple Linear Regression (MLR) analysis of SWC was conducted in order to highlight possible dependencies of SWC values. MLR highlighted significant dependency of SWC from the date of analysis, the position of the sample in the terraced slope, as well as a significant positive correlation of SWC with the percent of Water Stable Aggregates (WSA) analyzed at the study sites. Since high soil disturbance induces low soil aggregates stability, this result shows how measures to reduce soil disturbance during implementation can significantly increase SWC of radical terraces. Overall, the results of the present paper testify the good performances of bench terraces in Northern Ethiopia in terms of water conservation, and this first benchmark study can inform future terracing implementation in some arid and semi-arid agricultural areas of the world.</p><p>The abstract is based on Mesfin, S.; Almeida Oliveira, L.A.; Yazew, E.; Bresci, E.; Castelli, G. Spatial Variability of Soil Moisture in Newly Implemented Agricultural Bench Terraces in the Ethiopian Plateau. Water 2019, 11, 2134.</p>

Evaporites reveal Pleistocene basin dynamics in the Danakil depression (northern Afar, Ethiopia)

<p>The Danakil depression (Afar, Ethiopia) is a rift valley forming the southernmost part of the Red Sea rift. It is situated between the Ethiopian plateau and the Danakil block and is thought to represent an advanced stage of rifting, characterized by important tectonic and volcanic activity. Its floor is situated 120 meters below sea level and is covered by salt pans.</p><p>This study focuses on a 625 m deep borehole drilled in the central part of the basin. It mainly consists of evaporites dominated by halite along with clastic and carbonate sediments. Lithostratigraphy and facies description were completed by micropaleontological, geochemical, mineralogical and organic matter analysis. They reveal the complex history of this rift basin. Two marine Red Sea incursions are identified. Strong water stratification during the older marine incursion led to the formation of sapropel layers and magnesite. The restriction of the basin and the strong aridity led to the formation of evaporites, culminating in the deposition of potash salts. Between the two marine events, continental evaporites contributed to several hundreds of meters of basin fill.  The younger marine incursion was probably characterized by wetter environments, resulting in the deposition of smaller volumes of evaporites. Since then, hypersaline lakes and salt pans filled the basin. Ongoing radiocarbon and U/Th datings will constrain further the Pleistocene stratigraphy and timing of the marine incursions.</p><p>These findings shed a new light on the basin history. The successive flooding and desiccation events are a consequence of sea-level variations but also important tectonic activity. Rift margin uplift prevented flooding during the Holocene sea-level highstand and contributed to the restriction of the depression. Significant basin subsidence at very short time scales created accommodation space for the voluminous sediment infill. This implies very active rifting during the last 250 ka.</p>

Spatial Variability of Soil Moisture in Newly Implemented Agricultural Bench Terraces in the Ethiopian Plateau

In arid areas prone to desertification and soil erosion, the effectiveness of radical bench terracing in reducing drought risk is dependent on its correct implementation. However, the relationship between proper terracing implementation and the landscape capacity of holding soil moisture is still not understood. Moreover, spatial patterns of Soil Water Content (SWC) within the same terraced hillslope are weakly studied. The present paper analyses SWC variations in four newly implemented terraced sites in Tigray Region, Ethiopia. In all sites, terraced areas show SWC significantly higher than non-terraced ones, with the lower part of the terraced hillslope more humid than the others. A Multiple Linear Regression (MLR) analysis highlighted significant dependency of SWC from the date of analysis, the position in the terraced slope, and its significant positive correlation with the percent of Water Stable Aggregates (WSA) analyzed at the study sites. Since high soil disturbance induces low soil aggregates stability, this result shows how low soil disturbance can significantly increase SWC of radical terraces. Overall, the results of the present paper testify the good performances of bench terraces in Northern Ethiopia in terms of soil water conservation, and can represent a benchmark study informing future terracing implementation in some arid and semi-arid agricultural areas of the world.

Small terrestrial mammal distributions in Simien Mountains National Park, Ethiopia: A reassessment after 88 years

Little is known about the distribution and ecology of small mammals inhabiting Simien Mountains National Park despite the presence of mostly endemic species. Prior to this study, the most comprehensive dataset was collected in 1927. This provides a unique opportunity to assess the possible role of climate change over the last 88 years on the elevational distribution of mammals in the Ethiopian highlands. Between September and November 2015, three of us (EWC, WTS, YM) collected non-volant small mammals at four sites (2900, 3250, 3600, and 4000 m a.s.l.) along the western slope of the Simien Mountains using standardized sampling. Over a four-week period we recorded 13 species, comprising 11 rodents and two shrews, all endemic to the Ethiopian Plateau. We found greatest species richness at mid-elevations (3250 m), consistent with a general pattern found on many other mountains worldwide but less so in Africa. We discovered one potentially new species of shrew. No previously unrecorded rodent species were observed. Finally, we compared our species distribution results to the 1927 dataset and found upward elevational shifts in species ranges, suggesting the role and influence of climate change on the small mammal community. Simien Mountains National Park represents an exceptionally valuable core area of endemism and the best protected natural habitat in northern Ethiopia.