Given the rapid rise in human population and increasing urbanization,it is important to understand their potential impacts on biodiversity.From March 2007 to August 2007,we conducted bird surveys in 90 strip transects...Given the rapid rise in human population and increasing urbanization,it is important to understand their potential impacts on biodiversity.From March 2007 to August 2007,we conducted bird surveys in 90 strip transects,each 3 km long and 100 m wide,along a gradient of urbanization in Hangzhou,China.This gradient spanned a range of urbanization levels including urban areas,rural-urban continuum areas,farming areas,mixed forest/farming areas and forested areas.We recorded 96 breeding bird species and classified them into nine functional groups based on nesting requirements.The nine functional groups consisted of canopy nesters,shrub nesters,canopy/shrub nesters,natural cavity nesters,building nesters,natural cavity/building nesters,ground nesters,water surface nesters and parasitic nesters.Species and functional diversities were estimated based on the Shannon-Wiener index.Environmental data of each transect as human disturbance,vegetation cover and building index were also measured,and a synthetic urbanization index of each transect was introduced based on these data.We used regression analyses to model the relationship of species abundance,species diversity,functional abundance and functional diversity with this synthetic index.The results show that urbanization significantly reduces species richness,species diversity,functional richness and functional diversity,but the specific patterns differed.The relationship between species abundance/species diversity and urbanization is linear.In contrast,the relationship between functional diversity and urbanization was quadratic.In other words,with increased urbanization,functional diversity declined only slightly at first but then dropped at an accelerating rate.This implies that,although moderate urbanization reduces species diversity of breeding birds,it affects functional diversity of breeding birds only slightly in Hangzhou.The regression analysis of species diversity and functional diversity suggests a quadratic relationship between species diversity and functional diversity,i.e.,a linear relationship between species diversity and functional diversity can only exist at low diversity levels across urbanization gradients and increasing species abundance does not lead to an increase in functional diversity at the highest diversity levels.展开更多
This paper will look at the importance that the migrant labors in China are doing today. The main question posed in this paper is “how migrant labors in China are contributing to rural development？”. Furthermore, t...This paper will look at the importance that the migrant labors in China are doing today. The main question posed in this paper is “how migrant labors in China are contributing to rural development？”. Furthermore, the paper will answer the following sub-questions： （1） Is migration an important factor in the development of rural areas？ （2） Can migration bridge the poverty gap between urban and rural areas？ The objectives of this paper are the following： （1） to identify the migrant labors contributions in China’s rural development; （2） to look into the importance of migration for the rural Chinese; and （3） to know and analyze the problems that migrant workers in China are facing in relation to their migratory work. Furthermore, this paper posits that migrant labors in China are contributing to rural development through their remittances, their investments, and the new knowledge and techniques that they acquired in the urban areas which they share in their home areas. In addition to that, this research looks at the migrant labors’ remittances, their investments, and the new knowledge and techniques that they acquired in their home areas as their contributions to rural development.展开更多
We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the wat...We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.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 Natural Science Foundation of China (Grant No. 30670344)the Hangzhou Municipal Bureau of Forestry and Water Resources
文摘Given the rapid rise in human population and increasing urbanization,it is important to understand their potential impacts on biodiversity.From March 2007 to August 2007,we conducted bird surveys in 90 strip transects,each 3 km long and 100 m wide,along a gradient of urbanization in Hangzhou,China.This gradient spanned a range of urbanization levels including urban areas,rural-urban continuum areas,farming areas,mixed forest/farming areas and forested areas.We recorded 96 breeding bird species and classified them into nine functional groups based on nesting requirements.The nine functional groups consisted of canopy nesters,shrub nesters,canopy/shrub nesters,natural cavity nesters,building nesters,natural cavity/building nesters,ground nesters,water surface nesters and parasitic nesters.Species and functional diversities were estimated based on the Shannon-Wiener index.Environmental data of each transect as human disturbance,vegetation cover and building index were also measured,and a synthetic urbanization index of each transect was introduced based on these data.We used regression analyses to model the relationship of species abundance,species diversity,functional abundance and functional diversity with this synthetic index.The results show that urbanization significantly reduces species richness,species diversity,functional richness and functional diversity,but the specific patterns differed.The relationship between species abundance/species diversity and urbanization is linear.In contrast,the relationship between functional diversity and urbanization was quadratic.In other words,with increased urbanization,functional diversity declined only slightly at first but then dropped at an accelerating rate.This implies that,although moderate urbanization reduces species diversity of breeding birds,it affects functional diversity of breeding birds only slightly in Hangzhou.The regression analysis of species diversity and functional diversity suggests a quadratic relationship between species diversity and functional diversity,i.e.,a linear relationship between species diversity and functional diversity can only exist at low diversity levels across urbanization gradients and increasing species abundance does not lead to an increase in functional diversity at the highest diversity levels.
文摘This paper will look at the importance that the migrant labors in China are doing today. The main question posed in this paper is “how migrant labors in China are contributing to rural development？”. Furthermore, the paper will answer the following sub-questions： （1） Is migration an important factor in the development of rural areas？ （2） Can migration bridge the poverty gap between urban and rural areas？ The objectives of this paper are the following： （1） to identify the migrant labors contributions in China’s rural development; （2） to look into the importance of migration for the rural Chinese; and （3） to know and analyze the problems that migrant workers in China are facing in relation to their migratory work. Furthermore, this paper posits that migrant labors in China are contributing to rural development through their remittances, their investments, and the new knowledge and techniques that they acquired in the urban areas which they share in their home areas. In addition to that, this research looks at the migrant labors’ remittances, their investments, and the new knowledge and techniques that they acquired in their home areas as their contributions to rural development.
基金funded by the“Technology Supporting Programme” of the “State Wetland Conservation Project for Lashihai Wetland”
文摘We studied the waterbird population at Lashihai Lake, Yunnan Province, China, which is a Ramsar Site(Wetland of International Importance), to determine seasonal variation in the species composition and size of the waterbird population. The study was conducted at five selected spots along Lashihai Lake at the same time each week from August 2011 to September 2013. In total, 62 waterbird species were recorded, of which 38.71%, 35.48%, 16.13%, and 9.68% were winter migrants, passage visitors, residents, and summer migrants, respectively. We found important seasonal changes in waterbird species composition and population size. Waterbird species richness was highest from September to the following April, with the total species numbers peaking in December. Total individual numbers peaked twice from late November to early December and mid-to-late February. However, waterbird species and individual numbers were comparatively lower from May to August. The change in species composition was determined by the arrival and departure dynamics of winter migrants and passage visitors. Winter migrants primarily caused the periodic changes in population size. Of concern,species and overall waterbird numbers seemed to be lower than the numbers in historical records. The decline of waterbird numbers implies that environmental changes caused by the implementation of the dam upstream of Lashihai Lake may have had adverse effects on this waterbird population. This study confirms the existence of major seasonal changes in species composition and size of the waterbird population at Lashihai Lake. Furthermore, the findings demonstrate that this wetland is of high conservation importance for waterbirds using the Central Asian–Indian and Asian–Pacific migratory routes.
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.
