Indices de structures spatiales des îlots de forêts denses dans la région des Monts Kouffé

La région des Monts Kouffé concerne ici la Forêt classée des Monts Kouffé et sa périphérie sud. Au Bénin, la Forêt classée des Monts Kouffé subit des pressions anthropiques qui ont pour nom une croissance démographique galopante, une agriculture itinérante sur brûlis, pâturage et braconnage anarchiques, exploitation forestière abusive, dysfonctionnement des écosystèmes forestiers et perte de la biodiversité. L’objectif général de cette étude est de caractériser les îlots de forêt dense de la forêt classée des Monts Kouffé en vue de mettre en exergue leur dynamique spatio-temporelle. La méthodologie adoptée est basée sur les techniques de la télédétection, de la cartographie et de l’écologie du paysage. À partir des images satellitaires Landsat TM de 1986 et ETM+ de 2006 toutes de 30 m de résolution spatiale, celles-ci ont permis le calcul des indices spatiaux comme le nombre de taches (ilots de forêts denses), l’aire totale des taches, la dominance, l’aire moyenne, la diversité des aires des taches et l’indice de forme.Monts Kouffe's region concerns here Monts Kouffe's forest reserve and its south suburb. In Benin, Monts Kouffe forest reserve undergoes anthropic pressures which are galloping population growth, a shifting cultivation, anarchy meadow and poaching, unfair forestry woods using, forested ecosystems' dysfunction and loss of biodiversity. The aim of this study is to characterize Monts Kouffe forest reserve and periphery’s dense forests islands in order to present their spatio-temporal dynamic. The adopted methodology is based on Remote Sensing, Cartography and Landscape Ecology techniques. From 1986 Landsat TM and 2006 Landsat ETM+ images for 30 m spatial resolution, these allowed the computation of spatial indexes as number of spots (dense forests islands), total area of spots, dominance, average area, spots areas’ diversity and, shape index

Indices de structures spatiales des îlots de forêts denses dans la région des Monts Kouffé

Monts Kouffe's region concerns here Monts Kouffe's forest reserve and its south suburb. In Benin, Monts Kouffe forest reserve undergoes anthropic pressures which are galloping population growth, a shifting cultivation, anarchy meadow and poaching, unfair forestry woods using, forested ecosystems' dysfunction and loss of biodiversity. The aim of this study is to characterize Monts Kouffe forest reserve and periphery’s dense forests islands in order to present their spatio-temporal dynamic. The adopted methodology is based on Remote Sensing, Cartography and Landscape Ecology techniques. From 1986 Landsat TM and 2006 Landsat ETM+ images for 30 m spatial resolution, these allowed the computation of spatial indexes as number of spots (dense forests islands), total area of spots, dominance, average area, spots areas’ diversity and, shape index

Simulation of the Impacts of Sea-Level Rise on Coastal Ecosystems in Benin Using a Combined Approach of Machine Learning and the Sea Level Affecting Marshes Model

Sea-level rise in Benin coastal zones leads to risks of erosion and flooding, which have significant consequences on the socio-economic life of the local population. In this paper, erosion, flood risk, and greenhouse gas sequestration resulting from sea-level rise in the coastal zone of the Benin coast were assessed with the Sea Level Affecting Marshes Model (SLAMM) using ArcGIS Pro 3.1 tools. The input features used were the Digital Elevation Map (DEM), the National Wetland Inventory (NWI) categories, and the slope of each cell. National Wetland Inventory (NWI) categories were then created using Support Vector Machines (SVMs), a supervised machine learning technique. The research simulated the effects of a 1.468 m sea-level rise in the study area from 2021 to 2090, considering wetland types, marsh accretion, wave erosion, and surface elevation changes. The largest land cover increases were observed in Estuarine Open Water and Open Ocean, expanding by approximately 106.2 hectares across different sea-level rise scenarios (RCP 8.5_Upper Limit). These gains were counterbalanced by losses of approximately 106.2 hectares in Inland Open Water, Ocean Beaches, Mangroves, Regularly Flooded Marsh, Swamp, Undeveloped, and Developed Dryland. Notably, Estuarine Open Water (97.7 hectares) and Open Ocean (8.5 hectares) experienced the most significant expansion, indicating submergence and saltwater intrusion by 2090 due to sea-level rise. The largest reductions occurred in less tidally influenced categories like Inland Open Water (−81.4 hectares), Ocean Beach (−7.9 hectares), Swamp (−5.1 hectares), Regularly Flooded Marsh (−4.6 hectares), and Undeveloped Dryland (−2.9 hectares). As the sea-level rises by 1.468 m, these categories are expected to be notably diminished, with Estuarine Open Water and Open Ocean becoming dominant. Erosion and flooding in the coastal zone are projected to have severe adverse impacts, including a gradual decline in greenhouse gas sequestration capacity. The outputs of this research will aid coastal management organizations in evaluating the consequences of sea-level rise and identifying areas with high mitigation requirements