The objective of this study is to characterize and assess the risk of collapse of woody plant formations in the Fathala forest. In recent years, this forest has suffered a sharp reduction in its plant cover to the poi...The objective of this study is to characterize and assess the risk of collapse of woody plant formations in the Fathala forest. In recent years, this forest has suffered a sharp reduction in its plant cover to the point of compromising the survival of populations of certain animal species such as the Red colobuses. The methods used are respectively constituted by the transect method, the dendrometric statements method and that of establishing the red list of ecosystems of the IUCN. The specific richness comprises 56 species divided into 47 genera and 22 families. The density is higher in the unfenced area (369 ind/ha in clear forest and 53 ind/ha in gallery forest) compared to the fenced area (160 ind/ha in clear forest versus 48 ind/ha in gallery forest). A study of the plant formations shows a strong degradation of the ecosystems passing from a clear and dry Sudanese forest to a wooded savannah. The cover rate in the fenced area is 20% in gallery forests and 25% in clear forests;in the unfenced area, it is 19% and 23% in gallery forests and clear forests, respectively. The application of the IUCN criteria shows an annual rate of collapse is -<span style="font-family:Verdana;">6 ind/ha in gallery forests and </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">4 ind/ha in clear forests. The annual rate of cover collapse would be </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">3.75% and </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">2.9% for gallery forests and clear forests, respectively. These results classify the forest in the Critically Endangered category. The main factors responsible for this degradation are, among others, anthropogenic actions and climatic pejoration. These results could constitute a basic tool for undertaking an improvement in the management of this forest, which is a living environment for an animal species.</span>展开更多
Mauritania, located in the Western Sahara, is one of the least developed countries in the Sahara Desert. Its capital, Nouakchott, which is home to 23% of its population, suffers from soil erosion from the Sahara and s...Mauritania, located in the Western Sahara, is one of the least developed countries in the Sahara Desert. Its capital, Nouakchott, which is home to 23% of its population, suffers from soil erosion from the Sahara and saltwater intrusion from the Atlantic Ocean. The local environment is under pressure from the combined effects of climate and socio-economic factors, with desertification being recognized as the greatest threat to life. In this context, high-resolution remote sensing images of Nouakchott obtained during the winters of 1985, 1988, 2000, 2006, and 2010 are selected for interpretation and classification. Analysis of the types of desertification and land use reveals the temporal and spatial characteristics of five distinct time periods from 1985 to 2010. This study analyzes the current status of desertification in Nouakchott and suggests five preventive measures.展开更多
文摘The objective of this study is to characterize and assess the risk of collapse of woody plant formations in the Fathala forest. In recent years, this forest has suffered a sharp reduction in its plant cover to the point of compromising the survival of populations of certain animal species such as the Red colobuses. The methods used are respectively constituted by the transect method, the dendrometric statements method and that of establishing the red list of ecosystems of the IUCN. The specific richness comprises 56 species divided into 47 genera and 22 families. The density is higher in the unfenced area (369 ind/ha in clear forest and 53 ind/ha in gallery forest) compared to the fenced area (160 ind/ha in clear forest versus 48 ind/ha in gallery forest). A study of the plant formations shows a strong degradation of the ecosystems passing from a clear and dry Sudanese forest to a wooded savannah. The cover rate in the fenced area is 20% in gallery forests and 25% in clear forests;in the unfenced area, it is 19% and 23% in gallery forests and clear forests, respectively. The application of the IUCN criteria shows an annual rate of collapse is -<span style="font-family:Verdana;">6 ind/ha in gallery forests and </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">4 ind/ha in clear forests. The annual rate of cover collapse would be </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">3.75% and </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">2.9% for gallery forests and clear forests, respectively. These results classify the forest in the Critically Endangered category. The main factors responsible for this degradation are, among others, anthropogenic actions and climatic pejoration. These results could constitute a basic tool for undertaking an improvement in the management of this forest, which is a living environment for an animal species.</span>
基金Chinese Academy of Sciences(2017-XBQNXZ-B-018)Science and Technology Partnership Program,Ministry of Science and Technology of China(KY201702010)China–Africa Joint Research Centre Project of the Chinese Academy of Sciences(SAJC201610)
文摘Mauritania, located in the Western Sahara, is one of the least developed countries in the Sahara Desert. Its capital, Nouakchott, which is home to 23% of its population, suffers from soil erosion from the Sahara and saltwater intrusion from the Atlantic Ocean. The local environment is under pressure from the combined effects of climate and socio-economic factors, with desertification being recognized as the greatest threat to life. In this context, high-resolution remote sensing images of Nouakchott obtained during the winters of 1985, 1988, 2000, 2006, and 2010 are selected for interpretation and classification. Analysis of the types of desertification and land use reveals the temporal and spatial characteristics of five distinct time periods from 1985 to 2010. This study analyzes the current status of desertification in Nouakchott and suggests five preventive measures.