https://hdl.handle.net/13049/16 Sat, 24 Oct 2026 02:27:38 GMT 2026-10-24T02:27:38Z https://hdl.handle.net/13049/847 Topographic modulation of drought propagation establishes low-elevation hotspots and mid-elevation climatic refugia in Southern Africa Tilahun, Minyahel; Tesfamichael, Solomon G.; Sasaki, Takehiro; Angassa, Ayana Drought dynamics across Southern Africa remain poorly understood, particularly regarding the topographic mechanisms that influence their spatial development and ecological consequences. Yet, the mechanisms by which local topography modulates drought propagation across elevation gradients, a key control on regional vulnerability, remain uncertain. We precisely quantify this critical mechanism. This study integrates high-resolution climate data (1950–2022) with future Standardized Precipitation Evapotranspiration Index (SPEI) projections to quantify three key aspects: 1) multi-year drought regimes, 2) topographic controls on drought propagation mechanisms, and 3) identification of hotspots of hydroclimatic vulnerability across various topographical complexities. We found the most severe long-term aridification occurs at higher elevations (2000–2500 m), where SPEI24 trends are strongest ( r = 0.6). In contrast, mid-elevation zones (1000–1500 m) displayed a persistent hydroclimatic buffer, exhibiting the slowest drought propagation rates and a decadal-scale shift toward shorter drought timescales, a pattern projected to intensify, with low-elevation zones accelerating toward more persistent drought conditions. This buffering effect, driven by orographic precipitation and reduced evaporative demand, creates distinct climatic refugia. Regionally, we identified a significant post-2000 expansion in the dominance of short-term droughts (SPEI01, SPEI03), with the fastest drought propagation in low-elevation and regional hotspots (e.g., Angola and Namibia). Our results demonstrated that drought development is fundamentally controlled by the interaction of timescale and topography. We, therefore, conclude that effective early warning systems must be spatially and temporally tailored by prioritizing rapid-onset agricultural alerts for lowlands while monitoring long-term hydrological deficits in high-elevation areas to mitigate ecological and societal consequences across Southern Africa. Journal Article Wed, 01 Apr 2026 00:00:00 GMT https://hdl.handle.net/13049/847 2026-04-01T00:00:00Z https://hdl.handle.net/13049/843 Trade-offanalysis between forest ecosystem services and disservices in the Bale Mountains eco-region, Southeast Ethiopia Ayana, Birhanu; Senbeta, Feyera; Seyoum, Aseffa Forests provide ecosystem services (ESs) and ecosystem disservices (EDs) to the local community living in and around the forest. The current study examined the trade-offs between forest ESs and EDs at different distances from the forest edge in southeast Ethiopia. The study employed a household survey, focus group discussions and field observations along six transects, laid down in a pair-wise design in six study villages. The study findings revealed that forests provide diverse services to the local community such as water sources (93.9%), firewood (89.40%), and woods for construction purposes (89.40%). Spatially, a significant statistical difference was observed between nearby and far away dwellers from forest edges about the perceptions of forest services; with more percentages being reported along the forest edges. Most respondents (59.1%) indicated their involvement in forest protection and tree plantation and retention in their land fields to augment ESs. Family size and education level were important factors determining the level of farmers’ participation in forest management. Similarly, diverse forest disservices were also reported by the farmers. Crop-raiding wild mammals such as porcupines (86.4%), bush pigs (83.3%), warthogs (72.7%), vervet monkeys (56.1%) and olive baboons (53%) were frequently cited as raiding one or more of crops, especially maize, in the study villages. Higher impacts of wild crop raiders were reported along the forest edges. Crop guarding (93.9%) was the most widely used disservices control measure. Hence, sustainable forest management strategies are required for mutual co-existence between crop-raiding wildlife and local communities to create a sustainable socio-ecological system. Journal Article Tue, 23 Jun 2026 00:00:00 GMT https://hdl.handle.net/13049/843 2026-06-23T00:00:00Z https://hdl.handle.net/13049/829 Effects of Seed Treatment and Bio-inoculants on Baikiaea plurijuga DC. and Pterocarpus angolensis Harms Seed Germination Makgobota, Kamogelo; Pule-Meulenberg, Flora; Angassa, Ayana; Rampart, Melusi; Mojeremane, Witness; Reinhold-Hurek, Barbara Background: This study examined the effect of pre-sowing seed treatments and microbial inoculation on the germination of Pterocarpus angolensis and Baikiaea plurijuga at the Botswana University of Agriculture and Natural Resources. Methods: This tree nursery study employed a 2 ×4 ×2 factorial, randomised experiment to test four pre-sowing treatments: Mechanical scarification, soaking in rainwater and warm water (40°C) and untreated seeds- alongside two levels of microbial inoculation: with and without B. ripae. Result: Mechanical scarification slightly improved germination, leading to earlier and more uniform germination in both species, with P. angolensis exhibiting a mean germination time of 10.5 days and a germination velocity coefficient of 9.57. P. angolensis germination decreased from 80.83% to 66.7%, indicating an incompatibility with B. ripae. Conversely, B. plurijuga germination increased from 70.84% to 91.67%. The findings demonstrate that scarification enhances germination in both species and can be used to improve native seedling protocols for the regeneration of dryland forests. © This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Sun, 01 Mar 2026 00:00:00 GMT https://hdl.handle.net/13049/829 2026-03-01T00:00:00Z https://hdl.handle.net/13049/828 Methane emissions from ruminant livestock in Ethiopia: Promising forage species to reduce CH4 emissions Berhanu, Yonas; Olav, Lars; Nurfeta, Ajebu; Angassa, Ayana; Aune, Jens B. This paper assesses the ability of fodder plants to reduce methane (CH4) emissions while simultaneously improving animal productivity in Ethiopia. Enteric CH4 emissions from ruminants in Ethiopia increased by 12% or 6197 Gg CO2-eq. in 2017 compared to the year 2011. In this study, six tropical multipurpose forages (Leucaena leucocephala (Lam.) de Wit, Moringa stenopetala (Bak.f.) Cuf., Sesbania sesban (L.) Merr., Cajanus cajan (L.) Millsp., Crotalaria juncea L., and Lablab purpureus L.(Sweet)) and maize stover were characterized in terms of chemical composition, in vitro CH4 production, and CH4 concentration (%). The objective was to identify forages with low CH4 production potential but with adequate forage quality. The forages differed significantly in chemical composition and in enteric CH4 emission. The dry matter (DM), ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) ranged between 89.4-95.4%, 6.08-12.5%, 3.3-30.7%, 20.4-76.0%, 10.8-44.8, and 2.9-14.1%, respectively. All forage plants, except maize stover, contained high CP content above a threshold value (i.e., 7%). Cajanus c. generates the lowest amount of CH4 (32.83 mL/0.2 g DM incubated). CH4 concentration (%) was used as a potential indicator to determine the capacity of a plant to lower CH4 production. Among the studied species, L. purpureus showed the highest CH4 reduction potential (16%) followed by C. juncea (23.45%), M. stenopetala (24.2%), and L. leucocephala (25.5%). Moringa s. was the most frequently preferred by the farmers followed by C. juncea and L. leucocephala. We concluded that M. stenopetala, C. juncea, and L. leucocephala can be promoted as valuable feed resources for ruminants while simultaneously reducing CH4 emissions. © 2019 by the authors. Journal article Tue, 01 Jan 2019 00:00:00 GMT https://hdl.handle.net/13049/828 2019-01-01T00:00:00Z