Assessment of Habitat Change Processes within the Oti-Keran-Mandouri Network of Protected Areas in Togo (West Africa) from 1987 to 2013 Using Decision Tree Analysis

Biodiversity conservation planning is highly important in the current context of global change. Biodiversity conservation can be achieved by understanding changes in land use at the landscape scale. Such understanding is needed to reverse the unprecedented pressure on natural resources that has been reported by many studies conducted on biodiversity conservation within the Oti-Keran-Mandouri protected areas. Land cover maps reflecting different dates (1987, 2000, and 2013) and depicting different management systems, with overall accuracy ranging from 73% to 79%, were analyzed to understand the processes that lead to habitat degradation within these protected areas. The nature of change, within a given land cover class, was determined by comparing land cover maps on different dates using a decision tree algorithm that compares the number of patches, their areas, and their perimeters at different time periods (T1 and T2). Specifically, two time-periods were considered for this analysis: 1987–2000 and 2000–2013. Croplands and settlements increased at an average of 108.13% and 5.45%, respectively, from 1987 to 2000. From 2000 to 2013, croplands gained from all other land categories and continued to increase at a rate of 11.77% per year, whereas forests and savannas decreased at an annual average rate by 5.79% and 2.32%, respectively. The dominant processes of habitat change from 1987 to 2000 were the creation of forests, dissection of savannas, attrition of wetlands, and creation of croplands. Meanwhile, from 2000 to 2013, there was attrition of forests, as well as attrition of savannas, dissection of wetlands, and aggregation of croplands. In general, from 1987 to 2013, natural habitats regressed and were replaced by croplands; forests, savannas, and wetlands decreased at an average annual percentage 5.74%, 3.94%, and 2.02%, respectively, whereas croplands increased at an average annual rate of 285.39% of their own area. Aggregation, attrition, dissection, and creation were the main habitat change processes identified for the overall period from 1987 to 2013. There was habitat loss in forests and savannas and habitat fragmentation in wetland due to attrition and dissection, respectively. Identifying and understanding habitat change processes would enable the taking of appropriate biodiversity conservation actions

Determination of Air Pollutant Concentrations in Plant Species in Relation to Pollution Sources

International audienc

Écologie et dynamique spatio-temporelle des mangroves au Togo

In Togo, the building of harbor facilities, the construction of the hydroelectric dam plant of Nangbeto, urban growth and activities relating to the installation of fish farms, and the expansion of croplands are the major causes of a drastic degradation of mangroves. For a better management of this ecosystem, assessment of the current structure of mangroves, their spatiotemporal dynamics and socioeconomic issues related to mangroves were performed. Data from forest inventory, structured interviews and Landsat images of 1986 and 2014 were used. Inventories have identified 23 plant species distributed among 23 genera and 17 families dominated by Rhyzophora racemosa and Avicennia germinans. The hierarchical classification of forest inventory samples has identified three groupings of mangrove plants. Investigations show that stakeholders use wood from the mangrove for energy and fuelwood purposes. From 1986 to 2014 the land use/land cover patterns in the study area has undergone tremendous changes. Floodplains and tannes find their areas increased by 39.91 % and 46.06 % respectively, while wooded vegetation cover in whole lost 47.19 % of its area. Anthropogenic pressures would be the main cause of the degradation affecting mangroves ecosystem services and productivity. However, due to the ecological importance of mangroves, there is a need for an appropriate management plan including the contextual realities of mangroves landscapes

Determination of the Types of Air Pollutants Prepondering in the City of Lome in Togo (West Africa)

International audienc

Écologie et dynamique spatio-temporelle des mangroves au Togo

Au Togo, l’installation des ouvrages portuaires, la construction du barrage hydroélectrique de Nangbéto, la croissance urbaine et les activités relatives à l’installation des bassins piscicoles, et l’expansion des aires de production en agriculture sont les causes majeures de la dégradation drastique des mangroves. Afin de contribuer à une meilleure gestion de cet écosystème, une évaluation de la structure actuelle des mangroves, de leur dynamique spatio-temporelle et des enjeux socio-économiques a été réalisée. Pour ce faire, des données d’inventaires forestiers, d’entretiens dirigés et des images Landsat de 1986 et de 2014 ont été utilisées. Les inventaires ont permis de recenser 23 espèces végétales réparties en 23 genres et 17 familles dominées par les Rhyzophora racemosa et Avicennia germinans. La classification hiérarchique des relevés d’inventaire forestier a permis d’identifier trois groupements végétaux de mangroves. Les résultats des enquêtes montrent que tous les acteurs utilisent le bois provenant de la mangrove pour des besoins énergétiques et de service. De 1986 à 2014, l’état des unités d’occupation du sol de la zone d’étude a subi d’énormes mutations. Les zones inondables et les tannes ont vu leurs superficies augmentées respectivement de 39,91 % et 46,06 % tandis que le couvert de végétation dense a perdu globalement 47,19 % (soit 829,82 ha) de sa superficie. Les pressions anthropiques seraient à l’origine de la dégradation des mangroves, impactant les services écosystémiques ainsi que leur productivité. Du fait de l’importance écologique des mangroves, il est urgent et nécessaire d’élaborer un plan d’aménagement adéquat prenant en compte les réalités actuelles.In Togo, the building of harbor facilities, the construction of the hydroelectric dam plant of Nangbeto, urban growth and activities relating to the installation of fish farms, and the expansion of croplands are the major causes of a drastic degradation of mangroves. For a better management of this ecosystem, assessment of the current structure of mangroves, their spatiotemporal dynamics and socioeconomic issues related to mangroves were performed. Data from forest inventory, structured interviews and Landsat images of 1986 and 2014 were used. Inventories have identified 23 plant species distributed among 23 genera and 17 families dominated by Rhyzophora racemosa and Avicennia germinans. The hierarchical classification of forest inventory samples has identified three groupings of mangrove plants. Investigations show that stakeholders use wood from the mangrove for energy and fuelwood purposes. From 1986 to 2014 the land use/land cover patterns in the study area has undergone tremendous changes. Floodplains and tannes find their areas increased by 39.91 % and 46.06 % respectively, while wooded vegetation cover in whole lost 47.19 % of its area. Anthropogenic pressures would be the main cause of the degradation affecting mangroves ecosystem services and productivity. However, due to the ecological importance of mangroves, there is a need for an appropriate management plan including the contextual realities of mangroves landscapes