Assouhan Jonas Atchadé

Climate change has become a serious threat to human life. This study aims to reveal the face of climate policies and the integration of urban adaptation into urban planning policies in the city of N’Djaména. To achieve this, we adopted a methodology combining both quantitative and qualitative approaches. Surveys of key informants were used to gather information on how to achieve the objectives set. The results show that key informants believe that climate policies have not met the expectations of the city’s citizens in terms of effectiveness and positive impacts. These players assume that urban policy planning does not take urban adaptation into account. The four categories of barriers hindering the integration of urban adaptation and its implementation relate to a lack of information and knowledge, political ill will, and organization and constraints linked to the mobilization and availability of resources. This study suggests the sharing of information, knowledge, and communication involving all stakeholders in N’Djaména’s urban development, the organization of the city’s state and municipal structures, the involvement and support of political authorities, greater access to financing, and the establishment of professional networks of expertise as catalysts for success.

Climate variability and change are already having a negative impact on the health of tens of millions of Africans through exposure to sub-optimal temperatures and extreme weather conditions as well as increasing the range and transmission of infectious diseases. This study aims to identify climate risks and the vulnerability of health systems as well as individual coping strategies in the city of N’Djaména. To achieve this, we adopted a methodology combining both quantitative and qualitative approaches. Meteorological data on wind, temperature, and rainfall were collected at daily and monthly intervals from the National Meteorological Agency in N’Djaména. Qualitative data were collected via focus group discussions with targets of the city’s health system and quantitative data were collected from the population on the basis of oriented questionnaires. The results show that rising temperatures with heat waves, regular flooding, and strong winds are the major climate risks identified. These have numerous impacts and effects on the city’s health system due to the following vulnerability factors most recognized by city dwellers: insufficient medical equipment in health facilities (IEME), the fragile nature of people’s physiological state in the face of climatic risks (CFEP), and the failure of city sanitation strategies and policies (DSPA). This study proposes a set of recommendations for transformational adaptation of the healthcare sector, which remains vulnerable to climate risks.

Urbanization is a current concern, particularly in Africa, where it is expected to continue and increasingly threaten the effectiveness of plant biodiversity, natural carbon sinks, and the sustainability of cities. This paper investigates the structural parameters and carbon storage potential of trees in the land use units of the city of Cotonou in southern Benin. A total of 149 plots at 2500 m² each were randomly generated, and trees with a diameter ≥ 10 cm were inventoried. ANOVA revealed that the means of structural parameters (diameter and height classes) and carbon stock rate varied significantly (p < 0.001) across land use units in the city. Tree basal area is estimated at 4.52 ± 5.24 m² ha⁻¹, with an average of 12.72 (13) feet ha⁻¹. The average diameter of the trees is estimated at 57.94 ± 29.71 cm. Approximately 1000 kg ha⁻¹ (0.94 × 10³ kg ha⁻¹) of carbon is stored in the city of Cotonou. Green spaces (1.21 × 10³ kg ha⁻¹) and roads (1.19 × 10³ kg ha⁻¹) are the units that recorded the highest carbon stocks. Khaya senegalensis, Mangifera indica, and Terminalia mentally lead the top ten species with high stock potential. This study demonstrates the contribution of urban trees to global atmospheric carbon reduction, which varies by species, land use units, and tree density. Future research could investigate an i-Tree Landscape approach for urban carbon estimation. This could reinforce urban carbon data availability for urban ecological planning.

Climate change and its corollaries suggest that urban planning tools and strategies need to integrate adaptation and resilience approaches into urban development. This study aims to inform decision makers and the scientific community of the importance of appropriating data on urban adaptation and resilience strategies in the city of N’Djaména. After sampling 519 city dwellers, oriented questionnaires and focus groups were used to collect socio-demographic parameters, major climate risks, their impacts on urban issues and the urban resilience strategies employed. The various exposure and impact indices were used to identify and prioritize climate risks and urban exposure issues with the populations concerned. The study highlighted three major climatic hazards, namely, flooding, heat waves and strong winds, and their impact on social and community facilities, the living environment and human health. Ten vulnerability factors have been identified, of which the intrinsically geophysical factors are most familiar to the city’s population. The principal component analysis (PCA) illustrates ten (10) strategies for adaptation and resilience to urban climate risks. To meet the climatic challenges in urban areas, this study makes several short-, medium- and long-term recommendations to decision makers.

Rapid urbanization and climate change effects may cause dramatic changes in ecosystem functions in cities, thereby inevitably affecting the growth performance of old trees. Few studies have explored species diversity and spatial differentiation in Benin urban areas. This study aims to explore this dimension of urban ecology in order to build resilience to climate change in the city of Cotonou. Its objective was to determine the predominant level of tree diversity in the city’s land use units. The urban green frame was subdivided into six land use units, namely, establishments, residences, green spaces, commercial areas, administrative areas, and roads. The forest inventories were carried out in 149 plots with surfaces evaluated at 2500 m² each. The IVI, an index that highlights the relative density, relative dominance, and relative frequency of species, has been used to characterize the place occupied by each species in relation to all species in urban ecosystems. This shows ecological importance through the diversity and quality of ecosystems, communities, and species. A total of 62 tree species in 55 genera and 27 families were recorded. The results show that the flora of the city of Cotonou is characterized by a strong preponderance of exotic species with some differences in species presence. The most abundant species with high ecological importance (IVI) in the different types of land use of the city are Terminalia catappa (IVI = 121.47%), Terminalia mantaly (IVI = 90.50%), Mangifera indica (IVI = 64.06%), and Khaya senegalensis (IVI = 151.16%). As the use of ecosystem services is recommended to tackle urban climate hazards, this study shows that direct development of this urban vegetation could improve the resilience of urban life to climate hazards through the provision of urban ecosystem services, potential ecological infrastructure foundations, and urban nature-based solutions.

Rapid urbanization and climate change effects may cause dramatic change of ecosystem functions in cities, thereby inevitably affecting the growth performance of ancient trees. Few studies have explored species diversity and spatial differentiation in Benin urban area. Here, we took Cotonou city to do that. The objective of the study conducted in the city of Cotonou, was to determine the predominant level of plant diversity in the city's land-use units. The urban green frame was subdivided into six land use units, namely establishments, residences, green spaces, commercial areas, administrative areas, and roads. The forest inventories were carried out in 149 plots with surfaces evaluated at 2500 m2 each. A total of 62 tree species in 55 genera and 27 families were recorded. The results show that the flora of the city of Cotonou is characterized by a strong preponderance of exotic species. The most abundant species with high ecological importance (IVI) in the different type of land use of the city are Terminalia catappa (IVI=121.47%), Terminalia mentally (IVI=90.50%), Mangifera indica (IVI=64.06%) and Khaya senegalensis (IVI=151.16%). This study shows that a directed development of this urban vegetation could improve the resilience of urban life to climate hazards through the provision of urban ecosystem services, potential ecological infrastructure foundations and urban nature-based solutions.

Anarchic urbanization and land artificialization expose urban ecosystems and ecosystem services (ES) to threat. Urban ecosystems and trees play a crucial role in improving urban environments, and their management depends on the perceptions and preferences of urban residents. An assessment of the socio-ecological factors determining the perception of the actors allows for the proper design and planning of ecological urban policies and urban adaptation to climate change. The objective of this work was to determine the key determinants (factors) of urban stakeholders’ perceptions of ES in generating socio-ecological information for planning and preservation of ecosystems in Cotonou municipality. In this way, we assessed the perception and discriminating variables of the different stakeholders of urban ES provided in the city of Cotonou. Thus, 381 city dwellers were individually interviewed after statistical sampling. Focus group discussions with the stakeholders also made it possible to highlight the ES provided in the different land use units (LU). The results show that 73.23% of the city dwellers agreed that they were aware of ecosystem services. The hierarchical classification shows two homogeneous groups of perceivers with ethnicity, age, and education as statistically discriminating sociological variables (pv ˂ 0.001). Urban dwellers in the city of Cotonou perceived more SEs in the cultural and regulatory services category significantly (pv < 0.001; v-test > 3). The principal component analysis (PCA) reveals the varying availability of ES according to the different LU in the city. It will be worthwhile to apply this study in the processes of decision-making in climate and environment policy planning for sustainable cities in Africa and all over the world because it adds scientific value.

Anarchic urbanization and land artificialization expose urban ecosystems and Ecosystem Services (ES) to the threat. Urban ecosystems and trees play a crucial role in improving urban environments, and their management depends on the perceptions and preferences of urban residents. An assessment of the socio-ecological factors determining the perception of the actors allows for the proper design and planning of ecological urban policies and urban adaptation to climate change. In this study, we assessed the perception and discriminating variables of the different stakeholders of urban ES provided in the city of Cotonou. Thus, 381 city dwellers were individually interviewed after statistical sampling. Focus group discussions with the stakeholders also made it possible to highlight the ES provided in the different Land Use Units (LU). The results show that 73.23% of the city dwellers agreed that they were aware of ecosystem services. The hierarchical classification shows two homogeneous groups of perceivers with ethnicity, age and education as statistically discriminating sociological variables (pv˂0.001). Urban dwellers in the city of Cotonou perceived more SEs in the cultural and regulatory services category significantly (pv3). The principal component analysis (PCA) reveals the varying availability of ES according to the different LU in the city. This study adds scientific value in the application of urban ecology to decision-making in climate and environment policy planning for sustainable cities in Africa and all over the world.