Habitat selection and food choice of White-naped Cranes(Grus vipio)at stopover sites based on satellite tracking and stable isotope analysis

By combining satellite tracking,land-cover extracted from Landsite 8 images,and the traditional stable isotope analysis,we studied the habitat selection and food preference of a vulnerable migratory waterbird,the Whitenaped Crane(Grus vipio),in one of its key stagging sites,the Shandian River Basin in the semi-arid northern China,to provide knowledge that is critical for its conservation in the Anthropocene.Our results showed that the White-naped Cranes used both uplands and natural wetlands in the stopover site.While the cranes used farmland and natural land cover equally as night-time roosting grounds,they spent most daytime foraging at farmlands.Despite the extensive usage of croplands as their foraging ground,the Bayesian mixing models based on stable isotopic analysis revealed that crop residues after harvesting,such as Maize(Zea mays)and Naked Oat(Avena chinensis),were only a small fraction of the White-naped Cranes’diet(~19%),and their diet composited mainly natural plants,such as Allium ledebourianum,Potentilla anserina,and P.tanacetifoli.Moreover,more than 20%of the total wetlands in the region were modelled as home range of the cranes.On contrast,less than 10%of croplands and about 1%of the unused uplands were identified as home range.In addition,the entire core habitats were located in natural wetlands.Our findings demonstrated the importance of natural wetlands for the survival of the threatened crane.However,the satellite-derived land cover data showed that croplands increased rapidly in the last decade in this area,at the expense of natural wetlands.With the sharp decrease of White-naped Crane population in China,the conservation of stopover sites becomes imperative.Based on our analysis,we recommend the following management actions:conserving adequate natural wetland area,regulating anthropogenic pressures such as the use of herbicides,expanding the duration and extent of current conservation regulations,establishing a comprehensive monitoring program,and initiating basin-scale ecological restoration,for effective conservation of this threatened species.These integrated conservation strategies for migratory waterbirds are necessary,considering the rapid land-cover changes and agricultural expansion that have been occurring in East Asian-Australasian Flyway,especially in the semi-arid temperate zone.

Impact of marsh changes on breeding cranes in Sanjiang Plain,northeastern China

In order to measure the impact of changes in the marsh on breeding Red-crowned Cranes (Grus japonensis) and White-naped Cranes (G.vipio) in the Sanjiang Plain,we conducted a complete crane súrvey in each of the summers of 2007 and 2008,and obtained information on the changes in its marsh through interpretation of satellite images in 1986,1995,2000 and 2005.A comparison between the 1984 and 2008 census shows that:1) the number of Red-crowned Cranes remained stable at about 300 birds,while the number of White-naped Cranes increased markedly; 2) the estimates of nests of Red-crowned cranes are close to the numbers of 1984,while approximately 90％ of the nests of these two crane species were distributed over five national nature reserves (NNRs); 3) the two crane species became more concentrated in three regions,i.e.,the Fuyuan Delta,the middle reaches of the Naoli and Qixing rivers,and the Xingkai Lake wetlands,rather as formerly in six regions.The area of the marsh decreased by 45％ within the 20-year period from 1986 to 2005.The major loss of the marsh area was in the form of a conversion to paddy fields and dry land,which can be primarily attributed to direct human activity under various economic and policy drivers.The disappearance of cranes in the Dulu and Abuqin rivers was induced by large-scale agricultural development.The fragmentation into and isolation of small areas of the marsh became increasingly more serious,which resulted in unsuitable condtions for crane breeding in small patches of the marsh.The number of cranes declined from 1984-1995 but had recovered remarkably by 2008,which may be due to theestablishment of a system of nature reserves,in place since 2000.The land ownership of the reserve plays a key role in maintaining the integrity of the wetland ecosystem,especially in Sanjiang,Honghe,Naolihe and Qixinghe NNRs,which together accommodated approximately 80％ of the population of cranes.However,we did not discover any nests at all in the provincial and municipal reserves,which may be attributed to high human disturbances in these areas.In the end,we propose some recommendations on reserve management.

白忱鹤迁徙路径与地面条件变化信息的遥感监测

据两千多年来的文字记载 ,候鸟适应了地球系统的气候环流、地表温度和湿地生态系统的分布与季节变化 ,选择了迁徙这种生存方式 ,幼年候鸟在迁徙往返中成长 ,候鸟种群在千里迁徙中优胜劣汰。传统监测候鸟迁徙路线的方法普遍采用的是环志法 ,这种方法的回收率为 1 0 %左右。近年来 ,我们与北海道环境研究所、东京大学 ,围绕鹤类鸟迁徙路径及其地面条件变化问题 ,开展了卫星跟踪数据、遥感成像数据、地表温度数据收集、处理和分析 ,得到了初步的结果。这项研究对中国东部经济快速发展地区和待振兴的东北老工业区的布局和发展 ,以及候鸟保护提供科学依据。本文主要介绍了具有代表性的候鸟 ,白忱鹤的迁徙路径监测和分析结果。

Integrating Wintering Waterbird Movements with Earth Observation Data of Wetland Dynamics

Wetlands are among the most productive and essential ecosystems on earth,but they are also highly sensitive and vulnerable to climate change and human disturbance.One of the current scientific challenges is to integrate high-resolution remote sensing data of wetlands with wildlife movements,a task we achieve here for dynamic waterbird movements.We demonstrate that the White-naped cranes Antigone vipio wintering at Poyang Lake wetlands,southeast of China,mainly used the habitats created by the dramatic hydrological variations,i.e.seasonal water level fluctuation.Our data suggest that White-naped cranes tend to follow the water level recession process,keeping close to the boundary of water patches at most of the time.We also highlight the benefits of interdisciplinary approaches to gain a better understanding of wetland ecosystem complexity.