scholarly journals Population size dynamics and spatial distribution of Tundra Swan Cygnus columbianus wintering in Poyang Lake

2018 ◽  
Vol 30 (6) ◽  
pp. 1646-1654
Author(s):  
WEI Zhenhua ◽  
◽  
LI Yankuo ◽  
SHAN Jihong ◽  
WANG Lingfeng ◽  
...  

2011 ◽  
Vol 21 (3) ◽  
pp. 260-265 ◽  
Author(s):  
PEIHAO CONG ◽  
LEI CAO ◽  
ANTHONY D. FOX ◽  
MARK BARTER ◽  
EILEEN C. REES ◽  
...  

Approximately 75% of the East Asian Flyway Tundra Swan Cygnus columbianus bewickii population winters in the Yangtze River floodplain, China. Historically the species was more widely distributed throughout the floodplain but now most of the population is confined to five wetlands in Anhui Province and to Poyang Lake in Jiangxi Province, where the majority (up to 113,000 birds) occur. Within-winter counts suggest that swans congregate at Poyang Lake before dispersing to other sites later in the winter. Counts show large between-year fluctuations, but suggest declines at Shengjin and Fengsha Lakes (both in Anhui) during the last five years. Declines at Shengjin Lake are likely due to decreases in submerged vegetation (particularly tuber-producing Vallisneria, a major food item) perhaps linked to eutrophication. Range contractions throughout the floodplain may also be linked to reductions in submerged vegetation coverage elsewhere. Changes in water quality and lake hydrology post-Three Gorges Dam may have adversely affected submerged vegetation productivity. Key information needs for the effective implementation of conservation measures for Tundra Swans include: (1) annual surveys of all major wintering sites throughout each winter to establish the importance of different sites during the non-breeding period; (2) more information on swan diets at important sites; and (3) an assessment of adverse effects of water quality and lake water levels post-Three Gorges Dam on submerged vegetation productivity at Poyang Lake and other important sites.



2013 ◽  
Vol 33 (18) ◽  
pp. 5768-5776
Author(s):  
戴年华 DAI Nianhua ◽  
邵明勤 SHAO Mingqin ◽  
蒋丽红 JIANG Lihong ◽  
杜建华 DU Jianhua ◽  
蒋剑虹 JIANG Jianhong ◽  
...  


2012 ◽  
Vol 14 (3) ◽  
pp. 327-337
Author(s):  
Yingying RAN ◽  
Juanle WANG ◽  
Yongjie ZHANG ◽  
Yujie LI ◽  
Yujie ZHOU


2012 ◽  
Vol 68 (4) ◽  
pp. 1135-1141 ◽  
Author(s):  
Chiquan He ◽  
Jiamiao Liu ◽  
Jun Li ◽  
Xia Liang ◽  
Xue-Ping Chen ◽  
...  




2002 ◽  
Vol 134 (5) ◽  
pp. 605-618 ◽  
Author(s):  
Sergei V. Mironov ◽  
Terry D. Galloway

AbstractFour new species of feather mites are described from birds in Canada: Megniniella ratcliffisp.nov. (Analgidae) and Metanalges holderisp.nov. (Analgidae) from the Sora, Porzana carolina (Linnaeus) (Gruiformes: Rallidae): Metingrassia pelecanisp.nov. (Xolalgidae) from the American White Pelican, Pelecanus erythrorhynchos Gmelin (Pelecaniformes: Pelecanidae); and Vingrassia cygnisp.nov. (Xolalgidae) from the Tundra Swan, Cygnus columbianus (Ord) (Ànseriformes: Anatidae). The genus Vingrassia is reinstated from its previous synonymy with the genus Ingrassia based on the presence of an enlarged prodorsal shield in both sexes, by the shape of the idiosoma and the interlobar membrane on the lobar apices in the male, and by the shape of the hysteronotal shield and the absence of setae ps2 in the female.



2019 ◽  
Vol 39 (14) ◽  
Author(s):  
张海娜 ZHANG Haina ◽  
鲁向晖 LU Xianghui ◽  
黄国敏 HUANG Guomin ◽  
李阳 LI Yang ◽  
王瑞峰 WANG Ruifeng ◽  
...  


2020 ◽  
pp. 121-130
Author(s):  
K. V. Samburov

The geographical distribution of 550 passenger railway nodes that are serving longer distance trains were studied. It’s containing 622 stations, which encompass more than 97% of passenger departures total number on the railway in 2016 were selected and grouped according to its size and the main nodes’characteristics were analyzed. Studying dependence of node’s rank and size from number of people, which live in its area, revealed that the less population size center is, the more other factors influence. The factual and ideal Zipf’s curve for the hierarchy of railway nodes were analyzed and its discrepancy was identified. An excessive role of Moscow as a main node and of Saint Petersburg as the second center is a feature in the hierarchy of nodes. This research also represents the analysis of nodes’ upper groups (more than 250 000 passenger departures per year). Spatial distribution of passenger railway nodes on the territory of Russia is descripted and the similarity of it with area of main resettlement was found. However, the density of relatively large nodes increases in Central and Central Black Earth economic regions and in Circum-Pontic region



2011 ◽  
Vol 24 (14) ◽  
pp. 3781-3795 ◽  
Author(s):  
Quan Dong ◽  
Xing Chen ◽  
Tiexi Chen

Abstract Many works suggest that the intensity of extreme precipitation might be changing under the background of global warming. Because of the importance of extreme precipitation in the Yellow–Huaihe and Yangtze–Huaihe River basins of China and to compare the spatial difference, the generalized Pareto distribution (GPD) function is used to fit the daily precipitation series in these basins and an estimate of the extreme precipitation spatial distribution is presented. At the same time, its long-term trends are estimated for the period between 1951 and 2004 by using a generalized linear model (GLM), which is based on GPD. High quality daily precipitation data from 215 observation stations over the area are used in this study. The statistical significance of the trend fields is tested with a Monte Carlo experiment based on a two-dimensional Hurst coefficient, H2. The spatial distribution of the shape parameter of GPD indicates that the upper reaches of the Huaihe River (HuR) basin have the largest probability of extreme rainfall events, which is consistent with most historical flood records in this region. Spatial variations in extreme precipitation trends are found and show significant positive trends in the upper reaches of Poyang Lake in the Yangtze River (YaR) basin and a significant negative trend in the mid- to lower reaches of the Yellow River (YeR) and Haihe River (HaR) basins. The trends in the HuR basin and the lower reaches of Poyang Lake in the YaR basin are nearly neutral. All trend fields are significant at the 5% level of significance from the Monte Carlo experiments.





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