摘要
The Red-crowned Crane (Grus japonensis) is a globally endangered species.Although this species has received much attention by scientists,conservationists and the general public,the continental population of the Red-crowned Crane continues to face serious threats which affect not only its population dynamics but also its breeding and wintering habitats.Habitat loss and deterioration are the main causes of the decline of its population.With the massive loss of habitats in all parts of its range - breeding,stopover and wintering grounds - the cranes have been forced into crops and farmlands where cranes are more vulnerable to human activities,such as poisoning the cranes and conflicts with farmers.From our review of studies done over 30 years,the eastern flyway subpopulation has been stable or slightly increasing and the western flyway subpopulation of the Red-crowned Crane has sharply declined in recent years.The wintering population for the western flyway has declined from over 1100 to less than 500 birds.Not only is the size of the population reduced to less than 50％,but most recently the decline has occurred with frightening speed,by 50-150 birds per winter.The current wintering range for the west flyway is only about 8％ of its extent in the 1980s.Urgent actions for habitat protection,law enforcement and education need to stop the declining trend for this species.
丹顶鹤(Grus japonensis)在全球范围受胁物种,数量是除美洲鹤(G.americana)外最少的鹤。尽管丹顶鹤一直受到鸟类学家、自然保护工作者和普通民众的广泛关注,但目前无论是从其种群动态,还是繁殖地和越冬地的栖息地状况来看,丹顶鹤的大陆种群都面临严峻的威胁。栖息地丧失和栖息环境恶化是导致种群数量下降的主要原因。在其整个分布区内——繁殖地、迁徙停歇地和越冬地——天然栖息地大量丧失,迫使丹顶鹤进入农田觅食。因此而导致这些鹤类更容易受到人类的伤害,如中毒或因损坏庄稼而与农民发生冲突。回顾30年的科学研究成果,利用东部迁徙通道的东部种群相对稳定或略有升高;而利用西部迁徙通道的西部种群数量下降。西部越冬种群的数量从多于1100只,到少于500只。这期间不仅仅是种群数量下降至不足原来的一半,更让人担忧的是近年来以每年冬天50–150只的惊人速度下降。目前,西部种群的越冬区域仅为上世纪80年代的8%。因此,亟待采取行动对丹顶鹤栖息地进行严格保护,加强执法力度和加大对民众的环境教育,以遏制这一物种数量下降的趋势。
