In order to analyze changes in human settlement in Xuzhou city during the past 20 years, changes in land cover and vegetation were investigated based on multi-temporal remote sensing Landsat TM images. We developed a ...In order to analyze changes in human settlement in Xuzhou city during the past 20 years, changes in land cover and vegetation were investigated based on multi-temporal remote sensing Landsat TM images. We developed a hierarchical classifier system that uses different feature inputs for specific classes and conducted a classification post-processing approach to improve its accuracy. From our statistical analysis of changes in urban land cover from 1987 to 2007, we conclude that built-up land areas have obviously increased, while farmland has seen in a continuous loss due to urban growth and human activities. A NDVI difference approach was used to extract information on changes in vegetation. A false change information elimination approach was developed based on prior knowledge and statistical analysis. The areas of vegetation cover have been in continuous decline over the past 20 years, although some measures have been adopted to protect and maintain urban vegetation. Given the stability of underground coal exploitation since 1990s, urban growth has become the major driving force in vegetation loss, which is different from the vegetation change driven by coal exploitation mainly before 1990.展开更多
Abstract： The Bogota Savannah was great Lake Humboldt 20,000 years ago. In the early 20th century, there were 50,000 ha of wetlands in Bogotá, but now this area has reduced to around 800 ha, due principally to h...Abstract： The Bogota Savannah was great Lake Humboldt 20,000 years ago. In the early 20th century, there were 50,000 ha of wetlands in Bogotá, but now this area has reduced to around 800 ha, due principally to human activities like industry, city-planning expansion, and agriculture. Actually, there are 13 wetlands and two lakes in Bogotá. SW （Salitre wetland） is an aquatic area that contains migratory and resident bird＇s species. Around this wetland, there are some urbanization and recreational areas that affect this natural habitat. Due to city-planning expansion, the city government wanted to build a great area to perform massive public events on the Salitre area. From June 2009 to June 2010, the researchers have made bird monitoring and recorded the SW as a very important habitat for birds; they demonstrated that this site offered them food and protection. Migratory species like Dendroica striata, Porzana carolina, Porphyrio martinica, Actitis macularia, Piranga rubra, Contopus cooperi and Contopus virens, inhabit this area. Most of the birds in SW use the area primarily for feeding and roosting, and the authors have recorded presence of eggs and chicks. In this way, the authors have demonstrated that this area is very important for migratory and resident birds. Currently, SW is in process to be officially designated as a wetland after many efforts. However, conservation and educational efforts should be taken into consideration for the protection and conservation of this wetland.展开更多
基金supported by the National High Technology Research and Developmemt Program of China (No2007AA12Z162)the Program for New Century Excellent Talents in University, Ministry of Education (NoNCET-06-0476)the Jiangsu Provincial 333 Engineering for High Level Talents(No.BK2006505)
文摘In order to analyze changes in human settlement in Xuzhou city during the past 20 years, changes in land cover and vegetation were investigated based on multi-temporal remote sensing Landsat TM images. We developed a hierarchical classifier system that uses different feature inputs for specific classes and conducted a classification post-processing approach to improve its accuracy. From our statistical analysis of changes in urban land cover from 1987 to 2007, we conclude that built-up land areas have obviously increased, while farmland has seen in a continuous loss due to urban growth and human activities. A NDVI difference approach was used to extract information on changes in vegetation. A false change information elimination approach was developed based on prior knowledge and statistical analysis. The areas of vegetation cover have been in continuous decline over the past 20 years, although some measures have been adopted to protect and maintain urban vegetation. Given the stability of underground coal exploitation since 1990s, urban growth has become the major driving force in vegetation loss, which is different from the vegetation change driven by coal exploitation mainly before 1990.
文摘Abstract： The Bogota Savannah was great Lake Humboldt 20,000 years ago. In the early 20th century, there were 50,000 ha of wetlands in Bogotá, but now this area has reduced to around 800 ha, due principally to human activities like industry, city-planning expansion, and agriculture. Actually, there are 13 wetlands and two lakes in Bogotá. SW （Salitre wetland） is an aquatic area that contains migratory and resident bird＇s species. Around this wetland, there are some urbanization and recreational areas that affect this natural habitat. Due to city-planning expansion, the city government wanted to build a great area to perform massive public events on the Salitre area. From June 2009 to June 2010, the researchers have made bird monitoring and recorded the SW as a very important habitat for birds; they demonstrated that this site offered them food and protection. Migratory species like Dendroica striata, Porzana carolina, Porphyrio martinica, Actitis macularia, Piranga rubra, Contopus cooperi and Contopus virens, inhabit this area. Most of the birds in SW use the area primarily for feeding and roosting, and the authors have recorded presence of eggs and chicks. In this way, the authors have demonstrated that this area is very important for migratory and resident birds. Currently, SW is in process to be officially designated as a wetland after many efforts. However, conservation and educational efforts should be taken into consideration for the protection and conservation of this wetland.
