Coordination of the aerial servey, the author carried ground census on the population size of Red-crowned crane(Grus japonensis) in Khanka Lakes District from 1984 to 1986. According to the census in spring of 1984, t...Coordination of the aerial servey, the author carried ground census on the population size of Red-crowned crane(Grus japonensis) in Khanka Lakes District from 1984 to 1986. According to the census in spring of 1984, the total number of Red-crowned crane is 72 individuals and 20 nests. So that this ground census has recorded 59 individuals more than the aerial survey of 13 individuals, and the percentage of nesting individuals in this flock is 55.6%, which is obviously higher than 36.9% of the average ratio in China. After this, in fall of 1984 and in spring of 1985 and 1986, we repeated the same censuses three times in the same districts, the results indicated that the flock of the crane in Khanka Lakes District is stable basically, but some individuals interchange with opposite flock of USSR because of gcgraphical adjoin.So, we believe this flock in China and that flock in USSR belong to the same population and suggest two countries should act in concert to studing on this population in future. Meanwhile, the aerial servey cooperate with ground census, it is the best way for reducing missing crane and achieving to high precision of census. From this, total number of Red-crowned crane in China is 542 individuals (483+59 ind ividuals).展开更多
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 s...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 attribute展开更多
文摘Coordination of the aerial servey, the author carried ground census on the population size of Red-crowned crane(Grus japonensis) in Khanka Lakes District from 1984 to 1986. According to the census in spring of 1984, the total number of Red-crowned crane is 72 individuals and 20 nests. So that this ground census has recorded 59 individuals more than the aerial survey of 13 individuals, and the percentage of nesting individuals in this flock is 55.6%, which is obviously higher than 36.9% of the average ratio in China. After this, in fall of 1984 and in spring of 1985 and 1986, we repeated the same censuses three times in the same districts, the results indicated that the flock of the crane in Khanka Lakes District is stable basically, but some individuals interchange with opposite flock of USSR because of gcgraphical adjoin.So, we believe this flock in China and that flock in USSR belong to the same population and suggest two countries should act in concert to studing on this population in future. Meanwhile, the aerial servey cooperate with ground census, it is the best way for reducing missing crane and achieving to high precision of census. From this, total number of Red-crowned crane in China is 542 individuals (483+59 ind ividuals).
基金supported by the Conservation Fund of the State Forestry Administration of China and the Siberian Crane Wetland GEF/UNEP Project(GF/2712-03-4627)
文摘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 attribute
