Background:The Bar-headed Goose(Anser indicus)breeds across the high plains and plateau of Central Asia and winters in the Qinghai-Tibet Plateau(QTP),the Yunnan-Guizhou Plateau and the Indian sub-continent.Of the two ...Background:The Bar-headed Goose(Anser indicus)breeds across the high plains and plateau of Central Asia and winters in the Qinghai-Tibet Plateau(QTP),the Yunnan-Guizhou Plateau and the Indian sub-continent.Of the two recognized discrete flyways of the Bar-headed Goose,the Eastern Tibetan Flyway(ETF)is the larger,comprising at least six migration routes.However,we remain ignorant about their migratory connectivity,habitat use and effectiveness of site-safeguard mechanisms set in place for the species.Methods:We tracked 30 ETF Bar-headed Geese from Chinese and Mongolian breeding areas to their wintering grounds using GPS/GSM transmitters,to determine their migration routes and stopover staging patterns within the QTP,overlaying these upon GIS layers of protected area status and habitat type,to model their habitat selection.Results:In total,14 tagged Bar-headed Geese provided information on their entire autumn migration and 4 geese on their entire spring migration.Qinghai Lake marked birds overwintered in the QTP(n=2),geese tagged in Mongolia wintered either in the QTP(n=3)or in India/Bangladesh(n=9),representing three of the migration routes within the ETF.In total,tagged birds staged at 79 different stopover sites within QTP in autumn and 23 in spring,of which 65%(autumn)and 59%(spring)of all fixes fell within the boundaries of either National Nature Reserves(NNRs)or Important Birds Areas(IBAs)in the QTP.Bar-headed Geese predominantly occurred on four land-cover types:grassland(mostly by day),water bodies(at night),wetlands and bare substrates(salt flats,dry lake/river substrates and plough)with little change in proportion.Generalized linear mixed models comparing presence with pseudo-absence data suggested geese strongly selected for wetlands as staging habitat,avoiding bare substrates in spring.Conclusions:Based on our limited observations of these tagged geese,this study is the first to show that the current designated National Nature Reserves in place in the staging areas within the QTP appear adequate to protect this increasing population.In addition,Hala Lake in Qinghai Province and adjacent areas used as initial QTP staging during autumn migration(currently outside of designated as NNRs/IBAs)are recommended for protection,based on their use by tagged birds from this study.Habitat modelling confirmed the importance of natural wetlands as feeding areas and safe areas of open water as roosting places.展开更多
Background:GPS/GSM tracking data were used to contrast use of(i)habitats and(ii)protected areas between three Arctic-nesting Greater White-fronted Geese(Anser albifrons,GWFG)populations throughout the annual cycle.We ...Background:GPS/GSM tracking data were used to contrast use of(i)habitats and(ii)protected areas between three Arctic-nesting Greater White-fronted Geese(Anser albifrons,GWFG)populations throughout the annual cycle.We wished to demonstrate that the East Asian Continental Population(which winters on natural wetlands in the Chinese Yangtze River floodplain and is currently declining)avoids using farmland at multiple wintering sites.We also gath-ered tracking evidence to support general observations from two increasing population of GWFG,the North Sea-Baltic(which winters in Europe)and the West Pacific(which winter in Korea and Japan)winter mostly within farmland landscapes,using wetlands only for safe night roosts.Methods:We tracked 156 GWFG throughout their annual cycle using GPS/GSM transmitters from these three popu-lations to determine migration routes and stopover staging patterns.We used Brownian Bridge Movement Models to generate summer,winter and migration stopover home ranges which we then overlaid in GIS with land cover and protected area boundary at national level to determine habitat use and degree of protection from nature conserva-tion designated areas.Results:Data confirmed that 73%of European wintering GWFG homes ranges were from within farmland,com-pared to 59%in Japan and Korea,but just 5%in China,confirming the heavy winter use of agricultural landscapes by GWFG away from China,and avoidance of farmland at multiple sites within the Yangtze River floodplain.The same GWFG used farmland in northeast China in spring and autumn,confirming their experience of exploiting such habi-tats at other stages of their annual cycle.Chinese wintering birds showed the greatest overlap with protected areas of all three populations,showing current levels of site safeguard are failing to protect this population.Conclusions:Results confirm the need for strategic planning to protect the East Asian Continental GWFG popu-lation.While the site protection network in place to protect the species seems adequate,it has failed to stop the declines.Buffalo grazing could serve as one simple strategy to improve the condition of feeding habitats at Dongting Lake and Poyang Lake in the Yangtze,where vast Carex meadows exist.In addition,while we warn against pushing GWFG to winter farmland feeding in China because of the long-term potential to conflict with agricultural interests,we recommend experimental sacrificial,disturbance-free farmland within designated refuge areas adjacent to the Yangtze River floodplain wetland reserves as a manipulative experiment to improve the conservation status of this population in years when natural food sources are limited.展开更多
叶面积指数(Leaf Area Index,LAI)是重要的植被结构参数,调控着植被与大气之间的物质与能量交换,在生态环境脆弱的我国西北部开展植被LAI的研究对阐明该地区植被对气候变化和人类活动的响应特征具有重要的科学意义。利用LAI-2200和TRAC...叶面积指数(Leaf Area Index,LAI)是重要的植被结构参数,调控着植被与大气之间的物质与能量交换,在生态环境脆弱的我国西北部开展植被LAI的研究对阐明该地区植被对气候变化和人类活动的响应特征具有重要的科学意义。利用LAI-2200和TRAC仪器观测了新疆喀纳斯国家级自然保护区森林和草地的有效叶面积指数(LAIe)和真实LAI,构建了其遥感估算模型,生成了研究区LAIe和LAI的空间分布图。在此基础上,分析了LAI随地形因子(海拔、坡度、坡向)的变化特征,探讨了将其应用于估算研究区森林生物量密度的可行性,并评估了研究区MODIS LAI产品的精度。结果表明:研究区阔叶林、针阔混交林、针叶林、草地LAIe的平均值分别为4.40、3.18、2.57、1.76,LAI的平均值分别为4.76、3.93、3.27、2.30。LAIe和LAI的高值主要集中分布在湖泊和河流附近;植被LAI随海拔、坡度和坡向的变化表现出明显的垂直地带性的特点。LAI随海拔和坡度的增加呈现先增加后减小的变化趋势,坡向对针叶林和草地LAI的影响明显,但对阔叶林和针阔混交林LAI的影响较弱;森林生物量密度(BD)随LAI增加而线性增加(BD=44.396LAI-25.946,R2=0.83),研究区森林生物量密度平均值为120.3 t/hm2,估算的总生物量为5.0×106t;MODIS LAI产品与利用TM数据生成的LAI之间具有一定的相似性(森林R2=0.42,草地R2=0.53),但森林和草地的MODIS LAI产品分别比利用TM数据生成的LAI偏低16.5%和24.4%。展开更多
为了研究大熊猫等珍稀动物的重要栖息地岷江冷杉林的林窗特征,采用样带法,研究不同海拔梯度带岷江冷杉林窗数量与密度、形状与大小结构、形成方式与时间、形成木种类与特征等。研究结果表明,岷江冷杉林林窗的线状密度和密度分别为51个/k...为了研究大熊猫等珍稀动物的重要栖息地岷江冷杉林的林窗特征,采用样带法,研究不同海拔梯度带岷江冷杉林窗数量与密度、形状与大小结构、形成方式与时间、形成木种类与特征等。研究结果表明,岷江冷杉林林窗的线状密度和密度分别为51个/km和25.5个/hm 2;随着海拔梯度的上升,林窗数量增多,其密度也随之上升;林窗以竖式林窗为主,占林窗数量的64.71%,以25~50 m 2和75~100 m 2范围内林窗个数最多,但75~100 m 2级别林窗面积为25~50 m 2级别的林窗面积的2.2倍;形成时间≥30年的林窗数量最多,占39.22%;林窗形成方式以树倒为主,其次为树干中部折断木,占形成木数量百分比分别为70.83%和14.58%;林窗形成木径级在31~40 cm范围和高度级在16~20 m范围内数量最多,分别占所有形成木数量的33.75%和38.33%。卧龙国家级自然保护区岷江冷杉林林窗随着海拔梯度的上升,林窗数量增多,其密度具有随之上升的趋势;岷江冷杉林以小林窗为主,形成时间≥30 a,形成木以树倒为主,径级在31~40 cm范围和高度级在16~20 m范围为主要特征。研究结论可以为近自然人工群落构建、人工促进更新,以及大熊猫栖息地退化生态系统恢复与重建提供理论依据。展开更多
基金Our study was supported by the National Natural Science Foundation of China(Grant No.31870369&No.31970433&No.31670424)China Biodiversity Observation Networks(Sino BON)The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the manuscript.
文摘Background:The Bar-headed Goose(Anser indicus)breeds across the high plains and plateau of Central Asia and winters in the Qinghai-Tibet Plateau(QTP),the Yunnan-Guizhou Plateau and the Indian sub-continent.Of the two recognized discrete flyways of the Bar-headed Goose,the Eastern Tibetan Flyway(ETF)is the larger,comprising at least six migration routes.However,we remain ignorant about their migratory connectivity,habitat use and effectiveness of site-safeguard mechanisms set in place for the species.Methods:We tracked 30 ETF Bar-headed Geese from Chinese and Mongolian breeding areas to their wintering grounds using GPS/GSM transmitters,to determine their migration routes and stopover staging patterns within the QTP,overlaying these upon GIS layers of protected area status and habitat type,to model their habitat selection.Results:In total,14 tagged Bar-headed Geese provided information on their entire autumn migration and 4 geese on their entire spring migration.Qinghai Lake marked birds overwintered in the QTP(n=2),geese tagged in Mongolia wintered either in the QTP(n=3)or in India/Bangladesh(n=9),representing three of the migration routes within the ETF.In total,tagged birds staged at 79 different stopover sites within QTP in autumn and 23 in spring,of which 65%(autumn)and 59%(spring)of all fixes fell within the boundaries of either National Nature Reserves(NNRs)or Important Birds Areas(IBAs)in the QTP.Bar-headed Geese predominantly occurred on four land-cover types:grassland(mostly by day),water bodies(at night),wetlands and bare substrates(salt flats,dry lake/river substrates and plough)with little change in proportion.Generalized linear mixed models comparing presence with pseudo-absence data suggested geese strongly selected for wetlands as staging habitat,avoiding bare substrates in spring.Conclusions:Based on our limited observations of these tagged geese,this study is the first to show that the current designated National Nature Reserves in place in the staging areas within the QTP appear adequate to protect this increasing population.In addition,Hala Lake in Qinghai Province and adjacent areas used as initial QTP staging during autumn migration(currently outside of designated as NNRs/IBAs)are recommended for protection,based on their use by tagged birds from this study.Habitat modelling confirmed the importance of natural wetlands as feeding areas and safe areas of open water as roosting places.
基金supported by the National Natural Science Foundation of China(Grant No.31970433)China Biodiversity Observation Networks(Sino BON)+1 种基金funded by the DLR(ICARUS directive)the Lower Saxony Ministry of Food and Agriculture and Consumer Protection。
文摘Background:GPS/GSM tracking data were used to contrast use of(i)habitats and(ii)protected areas between three Arctic-nesting Greater White-fronted Geese(Anser albifrons,GWFG)populations throughout the annual cycle.We wished to demonstrate that the East Asian Continental Population(which winters on natural wetlands in the Chinese Yangtze River floodplain and is currently declining)avoids using farmland at multiple wintering sites.We also gath-ered tracking evidence to support general observations from two increasing population of GWFG,the North Sea-Baltic(which winters in Europe)and the West Pacific(which winter in Korea and Japan)winter mostly within farmland landscapes,using wetlands only for safe night roosts.Methods:We tracked 156 GWFG throughout their annual cycle using GPS/GSM transmitters from these three popu-lations to determine migration routes and stopover staging patterns.We used Brownian Bridge Movement Models to generate summer,winter and migration stopover home ranges which we then overlaid in GIS with land cover and protected area boundary at national level to determine habitat use and degree of protection from nature conserva-tion designated areas.Results:Data confirmed that 73%of European wintering GWFG homes ranges were from within farmland,com-pared to 59%in Japan and Korea,but just 5%in China,confirming the heavy winter use of agricultural landscapes by GWFG away from China,and avoidance of farmland at multiple sites within the Yangtze River floodplain.The same GWFG used farmland in northeast China in spring and autumn,confirming their experience of exploiting such habi-tats at other stages of their annual cycle.Chinese wintering birds showed the greatest overlap with protected areas of all three populations,showing current levels of site safeguard are failing to protect this population.Conclusions:Results confirm the need for strategic planning to protect the East Asian Continental GWFG popu-lation.While the site protection network in place to protect the species seems adequate,it has failed to stop the declines.Buffalo grazing could serve as one simple strategy to improve the condition of feeding habitats at Dongting Lake and Poyang Lake in the Yangtze,where vast Carex meadows exist.In addition,while we warn against pushing GWFG to winter farmland feeding in China because of the long-term potential to conflict with agricultural interests,we recommend experimental sacrificial,disturbance-free farmland within designated refuge areas adjacent to the Yangtze River floodplain wetland reserves as a manipulative experiment to improve the conservation status of this population in years when natural food sources are limited.
文摘为了研究大熊猫等珍稀动物的重要栖息地岷江冷杉林的林窗特征,采用样带法,研究不同海拔梯度带岷江冷杉林窗数量与密度、形状与大小结构、形成方式与时间、形成木种类与特征等。研究结果表明,岷江冷杉林林窗的线状密度和密度分别为51个/km和25.5个/hm 2;随着海拔梯度的上升,林窗数量增多,其密度也随之上升;林窗以竖式林窗为主,占林窗数量的64.71%,以25~50 m 2和75~100 m 2范围内林窗个数最多,但75~100 m 2级别林窗面积为25~50 m 2级别的林窗面积的2.2倍;形成时间≥30年的林窗数量最多,占39.22%;林窗形成方式以树倒为主,其次为树干中部折断木,占形成木数量百分比分别为70.83%和14.58%;林窗形成木径级在31~40 cm范围和高度级在16~20 m范围内数量最多,分别占所有形成木数量的33.75%和38.33%。卧龙国家级自然保护区岷江冷杉林林窗随着海拔梯度的上升,林窗数量增多,其密度具有随之上升的趋势;岷江冷杉林以小林窗为主,形成时间≥30 a,形成木以树倒为主,径级在31~40 cm范围和高度级在16~20 m范围为主要特征。研究结论可以为近自然人工群落构建、人工促进更新,以及大熊猫栖息地退化生态系统恢复与重建提供理论依据。
