Browsing by Author "Mensah, Sylvanus"

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    Carbon Stock and Change Rate under Different Grazing Management Practices in Semiarid Pastoral Ecosystem of Eastern Ethiopia
    (Land, 2022) Gebremedhn, Haftay Hailu; Zewdu Kelkay, Tessema; Tesfay, Yayanshet; Tuffa, Samuel; Workeneh Dejene, Sintayehu; Mensah, Sylvanus; Mears Devenish, Adam John; Egeru, Anthony
    Grazing management strategies tend to have different effects on rangeland plant production. Changes in grazing management can, therefore, affect the carbon stock potential of rangelands. Despite rangeland ecosystems being important global sinks for carbon, we know relatively little about the effect of traditional grazing management practices on their potential to store carbon. In this study, we evaluated the carbon stock and change rate of rangelands using three traditional grazing management practices in the semiarid pastoral ecosystem of eastern Ethiopia. By comparing data on vegetation and soil carbon stocks, we found that there was a strong significant difference (p < 0.001) between these different management practices. In particular, the establishment of enclosures was associated with an annual increase in carbon stocks of soil (3%) and woody (11.9%) and herbaceous (57.6%) biomass, when compared to communal open lands. Both enclosure and browsing management practices were found to have the highest levels of soil organic carbon stocks, differing only in terms of the amount of woody and herbaceous biomass. Thus, modest changes in traditional grazing management practices can play an important role in carbon storage and sequestration. Further research is required on a wider range of traditional pastoral management practices across space and time, as understanding these processes is key to combating global climate change.
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    Interconnectedness of Ecosystem Services Potential with Land Use/Land Cover Change Dynamics in Western Uganda
    (Land, 2022) Kaheesi Kusiima, Samuel; Egeru, Anthony; Namaalwa, Justine; Byakagaba, Patrick; Mfitumukiza, David; Mukwaya, Paul; Mensah, Sylvanus; Asiimwe, Robert
    Understanding the evolution of land use/land cover change (LULCC) and how it shapes current and future ecosystem services (ES) supply potential remains critical in sustainable natural resource management. Community perception of historic LULCC was reconciled with previous study via remote sensing/geographical information systems using recall data in the Budongo–Bugoma landscape in Uganda. Then, a CA-Markovian prediction model of a LULC situation in 2040 under business as usual (BAU) and forest restoration scenarios was constructed. Additionally, we assessed the perceived proximate and underlying drivers of LULCC, and how LULCC shapes ecosystem services potential using household surveys. The perceived LULCC trend for the past three decades (1990–2020) corresponded with previous studies showing grassland, bushland, tropical high forest, and wetland cover declined greatly, while subsistence farmland, commercial farmland, and built-up areas had a great increment. The predicted LULC under (i) the business as usual scenario showed a continued decline of natural LULC while anthropogenic LULC increased greatly, tending to cover half of the landscape area; (ii) forest restoration under different levels showed an improvement of forest cover and other native LULC classes with a decline in mostly subsistence farmland. The proximate drivers were in three principal components (soil infertility, subsistence farming, drought; infrastructural development, commercial farming, overstocking of livestock, pest and disease challenges; tree planting), while underlying drivers were in two principal components (technology adoption, corruption of environment stewards, policy implementation gaps; cultural gaps). Food and cash crops were perceived to be the most important ecosystem services in the landscape. Generally, the landscape ES supply potential was dwindling and predicted to continue with a similar trend under BAU, despite the increment in ES contribution of subsistence and commercial farmland. Forest restoration would slightly improve the landscape ES potential but would cause a decline in subsistence farmland, which would result in either a threat to food/livelihood security or a livelihood shift. We recommend combined interventions that seek to achieve a progressive frontier that achieves development needs and priorities based on national need such as food security through local level production with recognition for sustainable availability of ecosystem services.
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    Socio‑economic factors influencing Afzelia africana Sm. use value and traditional knowledge in Uganda: implications for sustainable management
    (Environment, Development and Sustainability, 2021) Biara, Emmanuel; Egeru, Anthony; Mensah, Sylvanus; Biira Salamula, Jenipher; Kadigo, Mark Marvin
    Afzelia africana Sm. is a highly valued multi-purpose and overexploited tree species in Africa. Ethnobotany of A. africana can guide its sustainable usage, yet there is limited information on such aspect for the species in Uganda. Here, we assessed use values of A. africana and users’ traditional knowledge, and how they relate to plant parts and socioeconomic factors including ethnicity, gender, education, age, marital status, profession, household size, income, land size and livestock ownership. Two hundred face-to-face semi-structured interviews were conducted. Use values were assessed based on plant part value (PPV) and use value per use category ( UVk), while users’ traditional knowledge was compared using overall use value (OUV) and reported use value (RUV). All plant parts were used, with stem (PPV = 41.4%), seeds (19.6%) and leaves (19.3%) being the most important. Nine plant use categories were enumerated, with most dominant being material ( UVk = 0.63), followed by social (0.49) and fuel wood (0.41). Bark and root were mostly used for medicinal purpose, and branch and stem for fuelwood and material, respectively. Men and youngsters had higher OUV than females and older people, respectively. In particular, men frequently mentioned the use in agriculture, for fuelwood, environment and medicine, while women reported social use. Although socio-cultural group did not influence significantly OUV and RUV, multivariate analyses revealed differentiation in use category according to socio-cultural group. Land size also predisposed informants to report more uses for the species. Taking these significant socio-economic factors into account in participative forest management will facilitate A. africana sustainable use.
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    Vegetation structure, dominance patterns and height growth in an Afromontane forest, Southern Africa
    (Journal of Forestry Research,, 2020) Mensah, Sylvanus; Egeru, Anthony; Ephrem Assogbadjo, Achille; Gle`le` Kakaı, Romain
    Information on forest structure is fundamentally important to track successional vegetation dynamics for efficient forest management. This study reports on vegetation characteristics, dominance patterns and species height growth in a northern mistbelt forest type in South Africa. Common alpha-diversity indices (species richness and Shannon–Weiner diversity), structural vegetation parameters (tree density and basal area), and species importance value index were used. Size class distribution and height–diameter allometry were further examined for the overall stand and most important species. Stem densities (472.0 ± 43.5 and 605.3 ± 28.1 trees ha-1 for C 5 cm to\10 cm and C 10 cm dbh (diameter at breast height) classes, respectively) and basal area values (1.99 ± 0.19 and 48.07 ± 3.46 m2 ha-1, respectively) are comparable to other Afromontane forests in East Africa. The overall stand showed an inverted-J shaped distribution pattern which is a typical feature of stand size class distribution in most natural forests. Most ecologically important species also exhibited an inverted-J shaped distribution pattern, suggesting good regeneration and recruitment potential. There were significant differences in species on height, reflecting species-specific height growth patterns, possibly a result of intrinsic growth potential and competitive interactions. The present study suggests that conservation and management policies, including protection of surrounding land uses against fire, contribute to maintaining a successful recovery of these forests. However, it should be noted that these forests may be experiencing relatively slow dynamic flux as a result of the overmature state of some trees with several years under relatively strict protection.