Vegetation maps are crucial for ecologists and decision-makers, providing essential information on the spatial distribution of various vegetation types to support ecosystem exploration and management. Despite advancem...Vegetation maps are crucial for ecologists and decision-makers, providing essential information on the spatial distribution of various vegetation types to support ecosystem exploration and management. Despite advancements in Earth observation and machine learning enabling large-scale vegetation mapping, creating detailed and accurate maps in biodiversity hotspots remains challenging due to significant environmental heterogeneity and frequent human disturbances. The lack of sufficient ground-based data and complex climate-vegetation interactions further limits mapping accuracy. In this study, we developed an integrated framework for multi-source data fusion to enhance vegetation mapping and validation in Yunnan Province, a global biodiversity hotspot region in Southwest China. The mapping process involved four key steps:(1) vegetation classification using random forest and Landsat imagery,(2) boundary calibration based on a locally calibrated static climatevegetation model,(3) patch correction with independent forest inventory data, and(4) validation using adequate field observations. This approach enabled the mapping of 17 vegetation types and 44 subtypes in Yunnan Province(1:50000), categorized based on the growth-form composition of dominant species of the community. The overall accuracies were 0.747 and0.710 for natural vegetation types and subtypes, and 0.905 and 0.891 for artificial types and subtypes. This high-resolution map enhances our understanding of vegetation distribution and ecological complexity in this region, offering valuable insights for policymakers to support conservation efforts and sustainable management strategies.展开更多
Lancang-Mekong River Basin is one of ecoregions with rich biodiversity and high ecological values in the world. The basin has been strongly affected by human activities, particularly by dam construction. This study wa...Lancang-Mekong River Basin is one of ecoregions with rich biodiversity and high ecological values in the world. The basin has been strongly affected by human activities, particularly by dam construction. This study was conducted to investigate the vegetation distribution patterns in the dam areas along middle-low reach of the Lancang-Mekong River in Yunnan Province of China, where eight cascade dams have been planned or are being constructed. To identify the vegetation composition and structure, we sampled 126 quadrats along the transects arrayed vertically to both side of river channel from the year of 2004 to 2010. We found that the forest, shrub and grass communities were widely spread along the riverside. In low reach watershed of the Lancang-Mekong River, the dominated vegetations were grasses and shrubs which were severely disturbed by human activity. In middle reach of the Lancang-Mekong River, the dry-hot valley vegetation was found in the low valley. At high altitude, the pine forest and semi-evergreen seasonal forest were found. As a result of dam construction and operation, the structure and compositions of riparian vegetation were strongly changed. Some plants declined or disappeared due to the alteration of their habitats. The protection or restoration interventions are urgently needed to mitigate the risk of vegetation damage associated with dam projects along middle and low reach of the Lancang-Mekong River.展开更多
基金supported by the Major Program for Basic Research Project of Yunnan Province (Grant No. 202101BC070002)the Second Comprehensive Scientific Expedition of the Tibetan Plateau (Grant No. 2019QZKK04020101)。
文摘Vegetation maps are crucial for ecologists and decision-makers, providing essential information on the spatial distribution of various vegetation types to support ecosystem exploration and management. Despite advancements in Earth observation and machine learning enabling large-scale vegetation mapping, creating detailed and accurate maps in biodiversity hotspots remains challenging due to significant environmental heterogeneity and frequent human disturbances. The lack of sufficient ground-based data and complex climate-vegetation interactions further limits mapping accuracy. In this study, we developed an integrated framework for multi-source data fusion to enhance vegetation mapping and validation in Yunnan Province, a global biodiversity hotspot region in Southwest China. The mapping process involved four key steps:(1) vegetation classification using random forest and Landsat imagery,(2) boundary calibration based on a locally calibrated static climatevegetation model,(3) patch correction with independent forest inventory data, and(4) validation using adequate field observations. This approach enabled the mapping of 17 vegetation types and 44 subtypes in Yunnan Province(1:50000), categorized based on the growth-form composition of dominant species of the community. The overall accuracies were 0.747 and0.710 for natural vegetation types and subtypes, and 0.905 and 0.891 for artificial types and subtypes. This high-resolution map enhances our understanding of vegetation distribution and ecological complexity in this region, offering valuable insights for policymakers to support conservation efforts and sustainable management strategies.
文摘Lancang-Mekong River Basin is one of ecoregions with rich biodiversity and high ecological values in the world. The basin has been strongly affected by human activities, particularly by dam construction. This study was conducted to investigate the vegetation distribution patterns in the dam areas along middle-low reach of the Lancang-Mekong River in Yunnan Province of China, where eight cascade dams have been planned or are being constructed. To identify the vegetation composition and structure, we sampled 126 quadrats along the transects arrayed vertically to both side of river channel from the year of 2004 to 2010. We found that the forest, shrub and grass communities were widely spread along the riverside. In low reach watershed of the Lancang-Mekong River, the dominated vegetations were grasses and shrubs which were severely disturbed by human activity. In middle reach of the Lancang-Mekong River, the dry-hot valley vegetation was found in the low valley. At high altitude, the pine forest and semi-evergreen seasonal forest were found. As a result of dam construction and operation, the structure and compositions of riparian vegetation were strongly changed. Some plants declined or disappeared due to the alteration of their habitats. The protection or restoration interventions are urgently needed to mitigate the risk of vegetation damage associated with dam projects along middle and low reach of the Lancang-Mekong River.
