Climate Change and Biodiversity - Batch 4

Ecological and Conservation Patterns of Wild Palm Species in the Context of Climate Change in Burkina Faso (West Africa)

2023-03-19T00:00:00Z

Ecological and Conservation Patterns of Wild Palm Species in the Context of Climate Change in Burkina Faso (West Africa) Zon, Aboubacar-Oumar Wild palms occur in tropical and subtropical regions where people use them for many purposes. Despite their low diversity in semi-arid and arid areas, they highly contribute to the livelihoods of local people. Therefore, the overexploitation and climate change threaten palms in arid and semi-arid areas. This study investigates the ecological and conservation patterns of wild palm species under current and future climatic conditions in Burkina Faso in order to propose sustainable management strategies for their conservation. The methods consist in a combination of individuals’ interviews (258 people surveyed), inventories (in 120 plots), direct observations, species distribution modelling and climate niche factor analysis. The interview reported the importance of seven palms species in Western Burkina Faso. The importance of wild palm species depends on socio-cultural factors such as ethnic group, gender and age category. Wild palms that are considered useful are the one benefiting much of conservation care (e.g. Borassus akeassii and Elaeis guineensis). The inventories showed that Borassus akeassii, Elaeis guineensis, Phoenix reclinata and Raphia spp. had instable populations in Western Burkina Faso. A diversity of trees species co-occurred with palms with a significant lowest diversity in Borassus akeassii habitats (30 species) compared to Eleais guineensis (97 species), Phoenix reclinata (63 species) and Raphia spp. (73 species). More than half (65%) of Phoenix reclinata juveniles come from tillering, while Borassus akeassii, Elaeis guineensis and Raphia spp. are regenerated only by seeds. The morphological assessment suggests that another species of Raphia, co-occurs with Raphia sudanica in Western Burkina Faso. This may increases the flora of native palms of the country to eight (8), including two species of Raphia. The species distribution models identified water related variables such as precipitation and topographic position index as determinant variables of palms distribution in Burkina Faso. The potential suitable areas of wild palms were comprised between 10 and 15 % of the country and are located in the Sudanian climatic zone under current climatic conditions. Climate change may induce range expansion (up to 28.51%) or contraction (up to -16%) depending on the palm species, global circulation models and climatic scenarios. The climate change vulnerability assessment indicates that Borassus akeassii is less vulnerable to climate change than Elaeis guineensis, Phoenix reclinata and Raphia sudanica. 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

Metacommunity Structure and Assemblage Processes of Fish, Macroinvertebrate and Phytoplankton in the Lower Niger River Basin, Nigeria

2023-06-15T00:00:00Z

Metacommunity Structure and Assemblage Processes of Fish, Macroinvertebrate and Phytoplankton in the Lower Niger River Basin, Nigeria Ugbor, Ogechi Nnabuchi Understanding ecological processes that drive metacommunity dynamics is essential for elucidating the mechanisms of community assembly and for guiding biodiversity conservation. To this end, the relative influence of local environmental and spatial factors in structuring the community composition of fish, macroinvertebrate and phytoplankton at 15 sampling sites along the longitudinal gradient of the Lower Niger River Basin (LNRB) was investigated in dry and rainy seasons. In addition, the beta diversity and its components (species replacement and richness difference) of the species and their underlying drivers were examined. The result of Redundancy analysis indicated that the community compositions (fish, phytoplankton and macroinvertebrate) in the upper region were influenced by high nutrient concentrations, attributable to arable and nomadic farming within the region. In contrast, downstream sites were characterized by high concentrations of suspended solids indicative of flooding and mining effects. Fish and phytoplankton community compositions strongly differed between the upper and lower regions probably because of the presence of dams along the channel of the river that may have interrupted migration and dispersal. However, macroinvertebrate community composition was homogenized despite the presence of barrier (dam) in the river channel. Probable explanation to this observation may be the arial dispersal mode of most macroinvertebrate species that allow them to track suitable environment for their survival. Variation partitioning revealed higher contributions of spatial than environmental predictors on fish and phytoplankton community compositions (revealing the effect of dispersal limitations), but the total predicted variance was higher during dry season. Differences in flow dynamics between upper and lower regions as attributable to black and white floods in the LNRB modify the connectivity between sites. Dispersal among sites may be more limited downstream than in the upper region, particularly in dry season, certainly because damming in the upper region also interrupts the natural flood regime such that there are low water levels in the lower region, which spatially isolate fish and phytoplankton communities at certain sampling sites. Environmental predictors were the determinants of macroinvertebrate community composition reflecting the strength of species sorting in structuring macroinvertebrate community in the LNRB. This study revealed weak beta diversity for all the species studied indicating low species turnover. The replacement component contributed most to the overall beta diversity and its components for all the studied species in the LNRB, an indication of the importance of species sorting. Whereas, spatial predictors explained fish total beta diversity and its components, environmental filtering was the primary driver of macroinvertebrate and phytoplankton total beta diversity and its replacement component. However, their richness difference components were explained by spatial factors. The varying local contribution to biodiversity (LCBD) by different sites shows that some sites along the longitudinal gradient of the LNRB requires restoration measures (e.g. Awuru) while others require conservation actions (e.g Jebba). Overall, the results of this study indicated that damming induced changes in physiochemical variables (e.g. nutrients), accompanied by alterations in flow regime and longitudinal connectivity, increased replacement and loss of taxa. These changes have consequently led to alteration of species community dissimilarity and affected the relative effects of environmental and spatial factors on local community compositions, beta diversity and its components. These findings suggested that conservation of fish, phytoplankton and macroinvertebrate diversity in afro-tropical rivers requires maintenance of both habitat heterogeneity (spatial variation in habitat conditions) and connectivity at the scale of entire river basins. 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

Impact de la culture du cacao sur la séquestration du carbone dans le sol et la communauté microbienne au Ghana et en Côte d'Ivoire

2024-03-09T00:00:00Z

Impact de la culture du cacao sur la séquestration du carbone dans le sol et la communauté microbienne au Ghana et en Côte d'Ivoire Kumah, Florence Jessica Akosua Results of the present study provide relevant social and ecological insights on cocoa agroforestry system in West Africa. In general, cocoa land use tends to have major implication on soil properties due to unstainable land conversion and management, and climate change, thereby making soils of these production systems function below their productive capacity and stability. Understanding how this cultivation system under climate change impact soil properties, and cocoa plant growth is crucial for sustainable soil management, climate change mitigation and conservation actions under climate and land use changes in Ghana and Côte d'Ivoire. Specifically, the study assessed farmers’ perceptions and views of relevant stakeholders of how sustainable agroforestry should be designed to be able to achieve climate change mitigation and biodiversity conservation through the cocoa supply chain in Ghana and Côte d'Ivoire. Evaluated the impact of cocoa agroforestry management on soil physico-chemical properties and soil organic carbon sequestration. It has also characterized soil microbial population and communities common to the cocoa agroforestry farms in these countries. Finally, it has determined the growth rate and anatomical traits, and the climate-growth relationship of cocoa trees. To achieve these objectives, a face-to-face interview and semi-structured questionnaire were used to assess 201 (CI=100 and GH=101) farmers’ perceptions of sustainable agroforestry, climate change mitigation and biodiversity conservation and how it can be achieved through the cocoa supply chain. Soil properties were analyzed from samples collected from the surface (0-15 cm) and subsurface (15-30 cm) soil depths of treatment plots from three stands of different aged cocoa agroforestry, designated as 5, 15 and 30 years old farms in Ghana and Côte d'Ivoire. Dendrochronological studies were used to investigate the anatomical growth responses of cocoa tree to climate. The results indicate that high proportion of the respondents (89 and 88 % from Côte d'Ivoire and Ghana respectively) were not very much aware of soil carbon and its management, agroforestry and biodiversity and lack knowledge of strategies through which they can be achieved on the cocoa farmers farm. Farmers were very much aware of the drivers of climate change. Further results show that soil organic carbon and microbial communities differed considerably between farms (5, 15 and 30 years old) and between sites. Generally, SOC, SOCD sequestration were higher in the cocoa agroforestry farms in Ghana than Côte d'Ivoire. The results further showed that 15 years old farm in both countries perform higher in terms of most of the soil properties measured. The results obtained indicate positive correlations between soil pH and soil nutrient and their interactions. Analysis of the anatomical characteristics of the wood of the cocoa tree revealed the formation of distinct growth rings. The results show irregular growth trends and anatomical vessel traits varied across farms. Climate has significant influence on the growth and anatomical characteristics of cocoa. The study shows that immediate calls for education and more training are needed on sustainable management practices within the cocoa agroforestry system, the reinforcement of soil system and restoration actions are crucial for achieving future agriculture and forest sustainability in Ghana and Côte d’Ivoire. 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

Biology, Ecology and Dynamics of African Hackberry [Celtis toka (Forssk.) Hepper & J.R.I. Wood] in two Climatic Zones in Burkina Faso (West Africa)

2023-03-31T00:00:00Z

Biology, Ecology and Dynamics of African Hackberry [Celtis toka (Forssk.) Hepper & J.R.I. Wood] in two Climatic Zones in Burkina Faso (West Africa) Dabre, Zaïnabou Climate change is defined as a change in the weather pattern of a location or region that devastates land, and terrestrial ecosystems and exacerbates human food insecurity. These changes have a significant impact on many people who are thought to be disproportionately vulnerable to the effects of climate change. To cope with and mitigate the effects of climate change, rural communities relied on forests, mainly multipurpose plants such as Celtis toka, for goods and services. The current study on Celtis toka, a threatened species in Burkina Faso, was conducted in this context. The main goal was to contribute to the best knowledge of Celtis toka biology, ecology, and threat factors in order to ensure its conservation and sustainable management under climate change and land use change in the Sudanian region of West Africa. Especially, the study aimed to (i) assess the traditional knowledge and management practices of Celtis toka, (ii) to analyse the impacts of land use and climate on the diversity, structure, and regeneration of Celtis toka natural stand, (iii) to determine the effects of climate on tree ring growth, wood anatomical patterns, and aboveground carbon stock, (iv) predict the impacts of climate change on the geographical distribution of Celtis toka. The method consisted of surveying 405 respondents in a semi-structured interview, forest inventories in 129 plots, tree ring analysis and species distribution modelling. Ethnobotany demonstrated that Celtis toka is a multiuse tree overharvested in Burkina Faso for mystic (11.62%), food (27.89%), fodder (18.97 %), and medical (14.92 %) uses. Overall, 290 woody species from 113 genera and 105 families were investigated in Celtis toka’s natural stand habitats. The diameter (adult) and the height (juveniles) class distribution showed the populations of Celtis toka are unstable due to overexploitation, lack of regeneration, fire, and animal grazing. Tree-ring analysis discovered distinct growth ring boundaries. Tree ring chronology showed that climate change may affect the growth of Celtis toka. Aboveground biomass (51.44 ± 6.87 to 69.21 ± 13.38 Mg/ha) and carbon stock (25.72 ± 3.43 to 34.60 ± 6.69 Mg/ha) differ significantly (P < 0.05) across the climatic zone and land use type designating that climate and land use type impact the carbon storage. Under current climatic conditions, about 54.77 % of Burkina Faso area was suitable for the conservation of Celtis toka. Under both emission scenarios, all climate models predicted a decrease in the extent of suitable habitats of Celtis toka at the horizons 2041-2060 and 2081-2100. Suitable areas are predicted to decrease from 20.65 % to 27.81 % under the scenario ssp245 and from 48.07 % to 48.83 % under ssp585 in 2041-2060. By 2081-2100, the ssp245 predicts drastic changes in the species' spatial patterns, with habitat loss ranging from 25.26 % to 47.85 % while the ssp585 projected a loss of suitable area from 53.27 % to 54.37 %. 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