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Effect of Forest Management on Carbon Stock of Tropical Moist Afromontane Forest

International Journal of Forestry Research 2022年第0期2022卷

作者： Daba, Damena Edae Dullo, Bikila Workineh Soromessa, Teshome Center for Environmental Science College of Natural and Computational Sciences Addis Ababa University Addis Ababa Ethiopia Plant Biology and Biodiversity Management College of Natural and Computational Sciences Addis Ababa University Addis Ababa Ethiopia

Moist tropical forests have a significant role in provisioning and regulating ecosystem services. However, these forests are under threat of deforestation and forest degradation. In Ethiopia, the moist evergreen Afromontane forests have the potential for carbon storage and support a high diversity of plant species. However, it is under severe threat of deforestation and *** investigation was conducted to obtain adequate information on the carbon stock potential of the moist Afromontane forest of southwestern Ethiopia. A comparison of carbon stock was conducted between disturbed and undisturbed forests. A systematic sampling design was applied for recording woody species and soil data. A total of 100 main plots of 400 m2 were laid to record trees and shrubs with a diameter at breast height (DBH) ≥ 5 cm. The soil data were collected from 1 m2 subplots established at the four corners and the center of each main plot. The DBH and height were measured to calculate the aboveground carbon of trees and shrubs with DBH ≥ 5 cm. A total of 68 tree and shrub species belonging to 59 genera and 33 families were recorded. The mean carbon stock density was 203.80 ± 12.38 t·ha-1 (aboveground carbon stock) and 40.76 ± 2.47 t·ha-1 (belowground carbon stock). The highest proportion of aboveground carbon (t·ha-1) (42.34%) was contributed by a few tree individuals with DBH > 70 cm. The soil organic carbon stock (SOCS) (t·ha-1) for the depth of 0-30 cm is ranging from 58.97 to 198.33 across plots;the mean is 117.16 ± 3.15. The carbon stored in the moist Afromontane forest indicates its huge potential for climate change mitigation. Therefore, for the enhancement of forest biodiversity and carbon sequestration effective conservation measure and sound management approach is essential. © 2022 Damena Edae Daba et al.

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The Golden Afromontane ecosystems at cross-road: Wetland-based upstream-downstream linkage in Genale Dawa River Basin

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Heliyon 2025年第2期11卷 e41658页

作者： Temesgen, Habtamu Ketema, Haile Kebede, Gezahegn Woldemariyam, Fikadu Tesfaye, Gebremedihin Dilla University College of Agriculture and Natural Resource Department of Natural Resource Management Dilla Ethiopia Adama Science and Technology University College of Natural and Computational Science Department of Applied Geology Adama Ethiopia Addis Ababa University Institute of Water Resource Addis Ababa Ethiopia

Understanding the relationship between land use and land cover (LULC) change and wetland-based ecosystem services (WESs) is crucial for sustaining wetlands and maintaining hydrological connectivity in the Genale-Dawa River Basin (GDRB). While the quantification of LULC change has received considerable emphasis, WESs are often overlooked in this region. This research aims to analyze LULC change and estimate the potential ecosystem services (ESs) provided by the GDRB. Data were collected through field observations, focus group discussions, and key informant interviews, with respondents selected using simple random and purposive sampling techniques. Landsat images between 2005 and 2020, along with documents review, were utilized to generate datasets. A stakeholders’ consultation forum and expert judgment were employed to understand the historical ecology of WESs in the GDRB. Results showed that: (1) LULC change occurred non-linearly in the GDRB, with agricultural land continuously increasing while forestland, woodland, and grassland decreased between 2005 and 2020;(2) the estimated ecosystem service value (ESV) of the GDRB was approximately US $10,360.28 million in 2005 and US $9033.06 million per year in 2020, indicating a decline of 12.81 %, resulting in a total net loss of US $1327.22 million from the basin. Although provisioning ESV has increased, regulating, supporting, and cultural ESVs have experienced significant losses. The increase in provisioning ESV does not compensate for the overall decline in ESVs in the GDRB. Soil compaction in the upstream part of the GDRB has diminished recharge potential and enhanced flooding downstream, jeopardizing sustainable hydrological connectivity in the basin. This situation has placed the basin at risk and at a critical crossroads. Notably, the upstream landscape is now more exposed to anthropogenic pressures than in the past, with clear impacts observed both locally and downstream. Therefore, robust law enforcement and awar

关键词： Afroalpine Afromontane Historical ecology Upstream-downstream Wetland

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Existence and convergence of commutative mappings on some results of fixed point theory in a class of generalized non-expansive mappings

arXiv

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arXiv 2022年

作者： Tadesse, Gezahegn Anberber Department of Mathematics College of Computational and Natural Science Addis Ababa University Ethiopia

In this paper, we introduce a commutative mappings satisfying the class of generalized nonexpansive mappings which is wider than the class of mappings satisfying the condition (C), so called Condition Bγ,µ. The results obtained in this paper extend and generalized non-expansive mappings and other results in this direction. Different properties and some fixed point results for the mappings are obtained *** Codes MCS-class: 47H10 Copyright © 2022, The Authors. All rights reserved.

关键词： Mapping

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Development of Suitable Magnetite–Diatomite Nanocomposite for Cd (Ii) Adsorptive Removal from Wastewater

SSRN

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SSRN 2023年

作者： Gusu, Gemechu Lemessa Chebude, Yonas Demesa, Abayneh Getachew Fadeev, Egor Koiranen, Tuomas Alemayehu, Esayas Africa Center of Excellence for Water Management College of Natural and Computational Sciences Addis Ababa University Addis Ababa Ethiopia College of Natural and Computational Science Wollega University Nekemte Ethiopia LUT School of Engineering Science LUT University Lappeenranta Finland Faculty of Civil & Environmental Engineering Jimma University Jimma Ethiopia

In this study, suitable nanocomposite materials were synthesized form magnetite precursor and diatomite via co-precipitation method. The efficiency of the materials in adsorbing Cd(II) from aqueous solutions was investigated in a batch experimental system. The physicochemical characteristics of the adsorbent were investigated through FTIR, XRD, BET, SEM-EDX, and VSM measurements. Box-Behnken design (BBD) was employed to optimize the most significant adsorption variables;initial pH, adsorbent dose (g), initial (Cd(II) concentration (mg), and contact time (min). Under the optimized conditions, a maximum adsorption capacity of 31.44 mg/g and a Cd(II) removal efficiency of 98.94 % were achieved. Isotherm studies indicated that the Temkin model provided the best fit for adsorption equilibrium compared to other models. In addition, the kinetic adsorption studies revealed that the pseudo-second-order model is the best fit model for the adsorption kinetic data. Moreover, thermodynamic studies suggested that the uptake of Cd (II) was exothermic and spontaneous under standard conditions. Furthermore, the magnetite-diatomite nanocomposite adsorbents exhibited good reusability and could be easily separated from the solution using an external magnet for recycling purposes. About 80 % of Cd(II) recovery was achieved when using HNO3 desorbing agents. This study demonstrates promising potential of magnetite-diatomite nanocomposite as a viable solution for remediation of Cd(II) contamination in diverse wastewater treatment scenarios. © 2023, The Authors. All rights reserved.

关键词： Nanocomposites

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Effectiveness of two-stage horizontal subsurface flow constructed wetland planted with Cyperus alternifolius and Typha latifolia in treating anaerobic reactor brewery effluent at different hydraulic residence times

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Environmental Systems Research 2020年第1期9卷 1-15页

作者： Alayu, Ermias Leta, Seyoum Department of Chemistry College of Natural and Computational Sciences Assosa University Assosa Ethiopia Center for Environmental Science College of Natural Science Addis Ababa University Addis Ababa Ethiopia

Background: Agro-industrial wastewaters in Ethiopia cause severe environmental pollution problems. Research evidence showed that anaerobic reactors are good options for the treatment of these wastewaters. But, their final effluent does not meet the discharge standards. Conversely, a series stage horizontal subsurface flow constructed wetland (HSSFCW) system is encouraging for the polishing of anaerobic reactor effluents. However, its treatment efficiency is dependent on hydraulic residence time (HRT). Cyperus alternifolius and Typha latifolia-based wastewater treatment showed good removal efficiencies individually. However, data on their combined treatment effectiveness is negligible. Therefore, this study assesses HRT influences on the treatment effectiveness of a two-stage HSSFCW system planted with these two macrophytes for the polishing of anaerobic reactor brewery effluent. A series connected two-stage HSSFCW unit planted with Cyperus alternifolius and Typha latifolia was built to treat Kombolcha brewery anaerobic reactor effluent. Then, the macrophytes were endorsed to grow with continuous application of diluted brewery effluent from a reservoir tank using gravity force. After dense stand formation, the experiment was initiated to determine the influence of HRTs on the removal efficiency of a complete wetland system. The system was operated sequentially by supplying fixed influent inflow rates of 2791, 1395, 930, 698, and 558 L day−1, respectively, for 1, 2, 3, 4, and 5 days HRT. Both the influent and effluent of the two-stage HSSFCW system were analyzed following common procedures for main brewery pollutants. Result: Results showed that as HRT increased from 1 to 5 days, the effluent pH and temperature were decreased along with enhanced pollutant removals ranging from 47.8–87.2%, 29.2–90.1%, 32.9–77.7%, 16.8–75.4%, and 18.4–76.8% with decreased influent mass loading rates ranging from 26.4–2.1, 64.5–7.3, 11.5–0.8, 5–0.6, and 3.8–0.4 gm−2 day−1, respectively,

关键词： Efficiency

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Temperature and Pressure-Induced Atomic Structure Evolution During Solidification of Zr50Nb50 Metallic Melt via Molecular Dynamics Simulation

arXiv

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arXiv 2023年

作者： Asefa, Frew Gashaw Ma, Yi Wu, Qin Mekonnen, Yedilfana Setarge Debela, Tekalign Terfa Material Science Program College of Natural and Computational Sciences Addis Ababa University P. Box 1176 Addis Ababa Ethiopia Key Laboratory for Light-weight Materials Nanjing Tech University Nanjing210009 China Center for Functional Nanomaterials Brookhaven National Laboratory UptonNY11973-5000 United States Center for Environmental Science College of Natural & Computational Sciences Addis Ababa University Ethiopia Institute for Application of Advanced Materials Jeonju University Chonju Korea Republic of

In this report, the evolution of the local atomic structure of the Zr50Nb50 melt was investigated by applying temperature (2600 to 300 K) and pressure (0 to 50 Gpa) using classical molecular dynamics simulations. To gain clear insight into the structural evolution during quenching, we used various methods of structural analysis such as the radial distribution function g(r), coordination number, bond angle distribution, and Voronoi tessellation. We found that the icosahedral motifs (which are the signature of the short-range ordering) and distorted BCC-like clusters dominate in the liquid and glass region under 0 and 5 Gpa external pressure. A first-order phase transition to a crystal-like structure was observed at 10, 15, and 20 Gpa external pressure at 1400, 1500, and 1600 K, respectively. Before the first-order phase transition, the system was dominated by icosahedral and distorted BCC-like clusters. When the temperature is lowered further below the glass transition at 10,15, and 20 Gpa external pressure, all structural analyses show that the solidified system consists mainly of body-centered cubic-like clusters in the case of our specific cooling rate of 1012 K/s. Copyright © 2023, The Authors. All rights reserved.

关键词： Binary alloys

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Status,approaches,and challenges of ecosystem services exploration in Ethiopia:A systematic review

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Chinese Journal of Population,Resources and Environment 2020年第3期18卷 201-213页

作者： Mekonnen Amberber Mekuria Argaw Gudina Legese Feyisa Sileshi Degefa Department for Environmental Science College of Natural and Computational SciencesKotebe Metropolitan UniversityAddis AbabaEthiopia Center for Environmental Science Addis Ababa UniversityAddis AbabaEthiopia

Healthy ecosystems benefit humans in various forms,and ecosystem services(ESs)are the benefits reaped by people in various ***,increase in global human population and the resulting anthropogenic activities have led to rapid alterations in the composition,structure,and functions of the ecosystems as well as their degradation,increasing the losses associated with ES *** of people in several developing countries are highly dependent on their surrounding ecosystems and the services they ***,management and reduction of ecosystem modification are required;especially in developing countries,this requirement is even more *** Africa,ecosystem-based studies are limited and in still in their initial ***,this paper examines dynamic Ethiopian ESs in Africa from 2010 to 2019 based on a systematic bibliometric analysis of articles from the Scopus database using a set of standard *** total,73 articles were published on Africa,including *** results reveal that the spatial distribution trend of ES studies is unevenly distributed,where most studies were conducted in the central highlands,followed by southwestern regions,with no studies on the western part of *** service providing units(SPUs),the urban ecosystem and agroecosystem accounted for 25%and mixed ecosystems accounted for 20%.Furthermore,a total of 67 specific ESs were investigated by researchers,among which 81.25%of the specific ESs were classified into two ES *** ES(40.29%)dominated across all of the ES types while the cultural ES(5.97%)type has received little *** on keywords,ESs were strongly linked to South Africa,Ethiopia,and *** terms of the co-authorship network,authors from the United Kingdom,Italy,Burkina Faso,the Netherlands,and Germany actively collaborated with the Ethiopian researchers,and approximately 50%of the studies were aimed at estimating the value of the ESs through an applied

关键词： Bibliometric analysis Challenge Ethiopia Ecosystem services Scopus

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Characterization of Chromogenic Bacteria Using Agro-Waste Extracts as Substrate for Pigments Production

SSRN

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SSRN 2024年

作者： Zeleke, Birhanu Muleta, Diriba Dinka, Hunduma Tsegaye, Dereje Ali, Jemal Hassen Department of Applied Biology School of Applied Natural Science Adama Science and Technology University Adama Ethiopia Environmental Biotechnology Unit Institute of Biotechnology Addis Ababa University Addis Ababa Ethiopia College of Natural and Computational Sciences Ethiopia Department of Applied Chemistry School of Applied Natural Science Adama Science andTechnology University Adama Ethiopia Adama Public Health Research Referral Laboratory Center Adama895067 Ethiopia Ethiopian Field Epidemiology Training Program Ethiopia

Background: Microbial pigments are becoming one of the important research areas to explore their potential as eco-friendly substitute to synthetic chemicals. Therefore, this research aims at exploring pigment producing bacteria as potential substitute to synthetic dyes by culturing on agro-waste ***: The study was conducted by collecting environmental samples from various sites in Ethiopia. The samples were serially diluted and inoculated on nutrient agar using streak plate technique for colony detection and isolation. Screenings for eco-physiological tolerance were conducted using one-variable-at-a-time-method on agro-waste extracts that were prepared by decoction method. Morphological, biochemical and MALDI-TOF techniques were used for identification of the pigment producing isolates. Solvent extraction method was employed for pigment extraction. The extracted pigments were characterized using ATR-FTIR, UV-Vis spectroscopy and LC-MS techniques. Results: A total of 1321 isolates were retrieved from the samples. The pigmented isolates were tolerant to incubation temperature between 28oC-45oC, pH 6-10, culture agitation between 60 rpm-120 rpm, salt concentration from 1% -5%, and glucose and yeast extract at 1% and 0.1%, respectively. The retrieved potent pigment producing isolates were identified as Kocuria rosea, Micrococcus luteus and Exiguobacterium auranticum. Among the isolates, Micrococcus luteus was found the major pigment producing from which 1.47 g/L of pigment produced using orange waste extract as substrate. The FTIR spectral analysis of the pigment demonstrated the presence of hydroxyl, alkane and alkene groups. Moreover, analysis of UV-Vis and LC-MS revealed that the organic species responsible for the pigmentation was carotenoid compound. The pigment was found temperature and pH sensitive compared to other factors. Conclusion: The study indicates the potential of Micrococcus luteus isolated from hot environment as a promising candidate for

关键词： Textile industry

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Insights of smallholder farmers on the trade-offs of eucalyptus plantation

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Environmental Challenges 2023年 10卷

作者： Desta, Takele Taye Teklemariam, Haimanot Mulugeta, Tewodros Department of Biology College of Natural and Computational Science Kotebe University of Education Addis Ababa Ethiopia Department of Forest Protection Ethiopian Environment and Forest Research Institute Addis Ababa Ethiopia

Eucalyptus is a popular evergreen perennial tree that grows quickly. Due to its diverse economic value and wide range of adaptations, the eucalyptus is commonly grown in tropical and subtropical regions. Eucalyptus is an economically important tree. However, the economic importance of eucalyptus ensued at the expense of undesirable ecological consequences. This qualitative study reports the advantages and disadvantages of eucalyptus woodlot establishment on the productivity of arable and grazing lands. In this study, nine knowledgeable farmers were involved in an in-depth individual interview and four focus group discussions were conducted. Farmers have frequently reported the negative impact of eucalyptus plantations on the productivity of the agricultural system. Eucalyptus serves as a refuge for crop pests and pathogens such as aphids and rust. Besides, the shade suppresses the development of the understory and adjacent crops, pastures, fodder, and other species of native trees and shrubs if they are planted together. Eucalyptus has increasingly replaced eco-friendly native trees and shrubs traditionally used as hedges, windbreaks, fodder, shelters for domestic and wild animals, and enhancers of soil fertility. Besides deteriorating soil fertility, structure, and moisture, it drains wetlands, springs, and streams and reduces the flow of rivers. Nevertheless, farmers acknowledged the importance of eucalyptus as a construction material, a source of fuelwood and charcoal, and income. To make the best use of eucalyptus woodlots without imposing adverse effects on agroecology, farmers have suggested that plantation sites should be marginally suitable for crop and livestock production. The expanded plantation needs to be contracted by removing a significant proportion of the established eucalyptus woodlots. Plantations of eucalyptus around watering points should be discouraged. Fast-growing, resilient, and eco-friendly tree species, such as those from Grevillea and Pop

关键词： Advantages and disadvantages Adverse impacts on ecosystem health Economic importance Eucalyptus woodlot plantation Smallholder farmers

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Assessing the impact of varying combined fertilizer rates on the yields of potato varieties in central Ethiopia

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Vegetos 2025年 1-14页

作者： Tulu, Getu Alemu, Nano Chala, Girma Crop and Horticulture Ethiopian Biodiversity Institute P.O. Box 30726 Addis Ababa Ethiopia Department of Plant Science College of Agricultural and Environmental Science Haramaya University P.O. Box 138 Haramaya Ethiopia Inorganic Soil Fertility Program Natural Resource Management Process Ethiopian Institute of Agricultural Research Holeta Agricultural Research Center P.O. Box 138 Holeta Ethiopia

The main constraints to potato productivity in the study area are low soil fertility and insufficient research-based guidance on the use of blended NPSB fertilizer across various potato varieties. Therefore, the experiment was conducted to evaluate the impact of varying rates of combined fertilizer on the yield components and traits associated with tuber yield in different potato varieties and computes the cost-benefit ratio of NPSB fertilizer rates for potato production in Walmara District. The study involved six (0, 100, 150, 200, 250 and 300 kgha⁻¹) NPSB fertilizer levels combined with three potato varieties, arranged in a factorial design with a randomized complete block setup, and each treatment was replicated three times. The outcomes indicated that, except for stem number, the interaction between NPSB fertilizer and potato varieties had a significant impact on all the tested parameters of potatoes. Belete variety resulted in a higher marketable tuber yield (279.48%) and yields of total tuber (223.23%) in 250 NPSB kg ha⁻¹ fertilization than without NPSB fertilizer. Based on partial budget analysis, the highest 254, 741 net benefits of Birr per ha with a 7684.2% return of marginal rate were observed from the Belete variety with the application of 250 kg ha⁻¹NPSB. Additionally, the Gudane variety with 300 kg ha⁻¹ NPSB fertilization had the highest net benefit with a reasonable marginal rate of return (2780%). Therefore, the tentative recommendation of this research was made toward the Belete variety with 250 kg ha⁻¹ NPSB and as a second option Gudane variety with 300 NPSB ha⁻¹ kg fertilization. © The Author(s) under exclusive licence to Society for Plant Research 2025.

关键词： Combined Fertilizer Marginal rate Tuber yields Varieties

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