http://197.159.135.214/jspui/handle/123456789/960 Thu, 06 Aug 2026 04:28:09 GMT 2026-08-06T04:28:09Z http://197.159.135.214/jspui/handle/123456789/1300 Effects of Climate Change and Forest Fragmentation on the Ecology and Genetic Diversity of White-Thighed Colobus, Colobus Vellerosus, West Africa Accrombessi, François Darius The white-thighed colobus (Colobus vellerosus), a Critically Endangered primate endemic to West Africa, faces imminent extinction due to rapid habitat loss, intense anthropogenic pressures, and accelerating climate change. For several years, it has been listed among the IUCN’s top 25 most endangered primates, underscoring the need for urgent and effective conservation actions. This dissertation presents the first comprehensive, multi-scalar assessment of the species' climatic niche, land-use dynamics within its distribution range, habitat connectivity, and genetic status. By integrating species distribution modelling, long-term landscape analysis, connectivity modelling, and population genetics, this work establishes a robust, spatially explicit foundation for needed conservation interventions. First, using ensemble species distribution models (SDMs) that disentangle climatic from anthropogenic effects, I show that precipitation during the driest month, annual mean temperature, and forest cover are the primary drivers shaping the distribution of C. vellerosus. Current anthropogenic pressures have already led to the loss of 36% of climatically suitable habitats, and even under an optimistic climate scenario, suitability is projected to decline by approximately 73% by 2050. Second, a 36-year land-cover analysis (1989-2025, corresponding to four generations of C. vellerosus) reveals pervasive landscape transformation across the species’ central Benin range. Forest cover has declined by 50% and savannah by 35%, while cropland expanded by 128%. Transition intensity analysis shows that conversions from forest to cropland and forest to settlement are dominant. This aligns with local perceptions, as 60% of surveyed residents acknowledged forest decline, though the accuracy of these perceptions varied only slightly with socioeconomic factors. These findings emphasise that anthropogenic land-use change is both extensive and community-recognised, yet insufficiently integrated into current management strategies. Third, a regional comparison of C. vellerosus and its parapatric congener C. polykomos demonstrates major mismatches between climatically suitable areas and current distributions, with both species exhibiting severe future range contractions. Although substantial areas of climatically suitable forest persist, 48–83% of these regions fall outside protected areas, underscoring potential opportunities for strategic habitat protection and planning for reintroduction. Fourth, through the modelling of functional connectivity via resistance surfaces in central Benin, least-cost paths, circuit theory, and graph-theoretic metrics, I demonstrate that fragmentation has resulted in a dual landscape: highly permeable corridors in the south (linking Monts-Kouffé, Kikélé, and Wari-Maro) contrasted with isolation in the north. The Monts-Kouffé–Wari-Maro complex emerges as the primary connectivity nucleus, with several medium-sized patches functioning as vital stepping stones, whose loss woulddisproportionately impair network integrity. Furthermore, mitochondrial DNA analysis of the two observable populations in central Benin (KSF and OKF) reveals extremely low genetic diversity, characterised by only one cytb haplotype and two nearly identical D-loop haplotypes, indicative of a severe founder effect and prolonged isolation. This significantly low mitochondrial variation highlights the urgent need for a comprehensive species-wide genetic assessment and the exploration of translocation-based genetic rescue strategies. Across all analyses, this dissertation illustrates that C. vellerosus faces significant threats from the simultaneous impacts of climate-driven niche contraction, long-term land-use transformation, severe habitat fragmentation, and dramatically reduced genetic diversity. Conservation priorities identified include: (1) protecting and restoring climatically resilient forest refugia, (2) enhancing community-managed and unprotected forests within connectivity networks, (3) establishing ecological corridors informed by functional connectivity outputs, (4) developing reintroduction and genetic rescue programs aligned with IUCN standards, and (5) integrating long-term ecological monitoring with community engagement and adaptive governance. Collectively, this work provides the first comprehensive conservation framework for C. vellerosus, from landscape to genome, offering actionable guidelines to prevent the extinction of one of West Africa’s most imperilled primates. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Université Félix Houphouët-Boigny, Côte d’Ivoire, in partial fulfillment of the requirements for the degree of Master of Science Degree in Climate Change and Biodiversity Thu, 09 Apr 2026 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/1300 2026-04-09T00:00:00Z http://197.159.135.214/jspui/handle/123456789/1299 Factors Controlling the Distribution of Desiccation-Tolerant Plants in West Africa Ibrahim Seidou, Wassila Biodiversity loss driven by human activities is accelerating globally, yet some functional groups remain largely overlooked in conservation planning. Desiccation-tolerant (DT) vascular plants, which can survive extreme dehydration, are among these overlooked taxa and face increasing threats from climate change and anthropogenic pressures. This thesis provides the first comprehensive assessment of desiccation-tolerant vascular plants in West Africa, a region of high biodiversity value and growing vulnerability to land-use change and climate extremes, addressing knowledge gaps in their diversity, distribution, ecological strategies, and conservation needs under global change. First, we compiled a checklist of DT species in the region, systematically reviewed the literature on their conservation status, and evaluated their representation in protected areas relative to anthropogenic threats such as quarrying and climate change. The results of this work show that only 14% of species have been assessed by the IUCN, and conservation needs are rarely discussed in the existing literature. Notably, the species that are the most exposed to threats were also the least represented in protected areas, which proved more effective at reducing quarrying impacts than at mitigating climate change. Second, species distribution models were used under current and projected climate scenarios, and the findings reveal a substantial contraction of distribution ranges, an increased fragmentation, and a significant reduction in species diversity and endemism centers. The findings highlighted the vulnerability of desiccation-tolerant plants to future climate conditions and the need to integrate climate-informed strategies into conservation planning. Third, the role of soil was explored in shaping intraspecific variation in ecological strategies among four selected desiccation-tolerant grasses. Although there are no significant relationships between soil variables and CSR strategies detected, the predominance of stress-tolerant strategies suggests an overriding influence of disturbance or other environmental drivers. Finally, experimental results demonstrated that seed age may compromise early seedling desiccation tolerance, revealing critical vulnerabilities during early life stages. This study stresses the urgent need to integrate desiccation-tolerant plants into biodiversity conservation frameworks through mechanistic, climate-informed approaches that account for species vulnerability in terms of exposure, sensitivity, and adaptive capacity. By combining ecological, physiological, and biogeographic perspectives, this work establishes a foundation for prioritizing desiccation-tolerant plants in conservation planning and provides actionable insights to enhance species persistence under increasingly water-limited conditions and the broader challenges of global change. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Université Félix Houphouët-Boigny, Côte d’Ivoire, in partial fulfillment of the requirements for the degree of Master of Science Degree in Climate Change and Biodiversity Thu, 09 Apr 2026 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/1299 2026-04-09T00:00:00Z http://197.159.135.214/jspui/handle/123456789/1298 Climate Threats and Human Activities on the Population Dynamics Of Detarium Microcarpum Guill. & Perr. In Burkina Faso Taonda, Adama Tropical savanna species influence ecosystem multifunctionality through the ecological mechanisms underlying the provision of multiple ecosystem services. Despite this functionality, anthropogenic factors such as deforestation, overexploitation of natural resources, extension of agricultural lands, overgrazing, and bushfires, coupled with the adverse effects of climate change, contribute to the loss of Detarium microcarpum. Within this context, this study aimed to contribute to the sustainable management and conservation of D. microcarpum in Burkina Faso. To achieve these goals, the methods have consisted of semistructured and focus group surveys of 465 people, 165 plots for forest inventories, tree rings and wood anatomy analysis, allometric equation and species modelling. The local population highlights the multipurpose uses of Detarium species and reveals the threats of the species are linked to the type of uses and the status of the site. A total of 102 woody species belonging to 79 genera rang in 28 families, were found in the natural habitats of D. microcarpum. The structure analysis reveals the unstable population of the species and the lack of regeneration. D. microcarpum showed distinct growth ring boundaries, the annual radial growth is positively related to precipitation during the end of the rainy for the current years but negatively to the previous years. Tree ring analysis revealed annual growth ring boundaries were 1.034 ± 0.425 mm. year-1. The above-ground biomass and above-ground carbon allocation are greater in the Sudano-Sahelian than in the Sudanian climatic zone. The allometric models established to predict D. microcarpum biomass were TAGB = e4.4002 (dbh*dbh*h) 0.9456 + e-3.5219 (dbh)2.4007 + e- 2.8845(dbh)1.3465 in the Sudanian zone and TAGB = e-4.1053 (dbh)2.4222 + e-5.2567(dbh)2.9539 + e- 2.9894(dbh)1.5285 for the Sudano-Sahelian climatic zone. The current suitability area for the species covers 65.6 % of the country area with respectively high suitability (36.73%) and low suitability (29.16%). Models projections indicate that highly suitable areas for Detarium microcarpum conservation are expected to decline under future climate change scenarios, regardless of the models used. The only exception is the MIROC6 model under the SSP5-8.5 scenario, which predicts a slight expansion of suitable habitats. The shift was observed from both unsuitable and highly suitable areas to the low-suitability areas in the model results across all climatic zones, with a notable progression in the Sahelian zone. Overall, this study provides important information for the sustainable use of D. microcarpum and the conservation guide for forest practices. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Université Félix Houphouët-Boigny, Côte d’Ivoire, in partial fulfillment of the requirements for the degree of Master of Science Degree in Climate Change and Biodiversity Thu, 13 Mar 2025 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/1298 2025-03-13T00:00:00Z http://197.159.135.214/jspui/handle/123456789/1297 The Potential of Mesophilic Bacteria for Heavy Metal Bioremediation in Agriculture under Climate Change in The Gambia Mendy, Anthony Crop and livestock production are critical to food security in The Gambia, yet yields have declined, partly due to the impacts of climate change and environmental pollution. This study investigated the potential of mesophilic bacteria (20-40 °C) for heavy metal bioremediation in agriculture under changing climatic conditions. Given the importance of groundnuts and rice, especially rice, consumed at 117 kg/person/year and cultivated across diverse ecosystems, the study explored farmers' perceptions of climate variability and pollution. A mixed-methods approach was used, with a quantitative sample size of 432 and qualitative data gathered through focus groups and eight key informant interviews across six agricultural regions. Results indicated widespread awareness among farmers of climate change, but limited knowledge of heavy metal pollution and bioremediation. Major constraints to production included poor access to water, credit, quality inputs, and rising salinity. Laboratory experiments isolated Pseudomonas fluorescens, Pseudomonas aeruginosa, Bacillus sp., and Grimontia hollisae for heavy metal bioremediation tests. Bacillus sp. exhibited the highest bioremediation efficiency, particularly on Cu and Fe media, reaching optical density (OD) values of 1.0 (Cu at 28 and 98 ppm, day 5) and 0.9 (Fe at 50 ppm, day 1) with sustained growth. P. aeruginosa showed immediate performance, ranking second in both Cu and Zn bioremediation. It achieved a rapid OD peak of 0.6 on day 1 at 58 ppm and demonstrated substantial growth in Zn media. P. fluorescens had the most robust and sustained OD responses across low and high Zn levels, although less than Bacillus sp. in Cu and Fe stress media. These performances indicated promise in Zn, Fe, and Cu remediation, thus highlighting their potential application in climate-resilient, pollution-aware farming practices. A Thesis submitted to the West African Science Service Centre on Climate Change and Adapted Land Use and the Université Félix Houphouët-Boigny, Côte d’Ivoire, in partial fulfillment of the requirements for the degree of Master of Science Degree in Climate Change and Biodiversity Thu, 11 Jun 2026 00:00:00 GMT http://197.159.135.214/jspui/handle/123456789/1297 2026-06-11T00:00:00Z