白鹇海南亚种的生态和现状

THE ECOLOGY AND SITUATION OF THE HAINAN SUBSPECIES OF SILVER PHEASANT

海南白鹇是仅分布于我国海南岛的特殊的白鹇海岛亚种。其结群个体少；雏鸟孵出后，每群雏数少；亲鸟损失严重，有极其罕见的纯雏群现象；种群繁殖力低，出生率仅７７．５％；保护区核心区种群密度１９７８年２０．２只／ｋｍ~２，１９９２年１２只／ｋｍ~２。天敌、人类危害是种群数量严重下降的主要原因。目前全岛有白鹇分布的残存林区面积仅７４０ｋｍ~２，乐观估计白鹇数量已不足８８００只，白鹇海南亚种已处于渐危至濒危级别，必须尽快采取有效的保护措施。

The authors studied the ecology of Silver Pheasant mainly by the method of observing at fixed spots with baits in Ba Wang Ling Nature Reserve on Hainan Island during the middle of 1986 through the end of 1993, they found that the existence of the Hainan subspecies of Silver Pheasant(Lophura nycthemera whiteheadi)was facing dangerous threatening.The number of individuals of the colonies of Hainan Silver Pheasant was low. l-6 in general, averaged 3.27± 1.49 on 48 colony-time;chicks in each colony were fairly few,commonly l-6 chicks carried by their parents,averaging 2.33± 1.33 on 18colony-time. Maximum 6 chicks appeared only once;loss of chicks was very severe so that only few of them became adults.At 6 observing spots-time,that have complete annual records,there were 12 chicks,in the second year there were only 5 left, rate of loss was 58.3%;loss of parent Pheasants was very severe so that we saw very rare phenomena,i.e.pure chick groups appeared 5 out 17 flocks; the rate of production was quite low,the natality was only 77.5%; even the density of population in the core of reserves was quite low and was rapidly decrease as well. In 1987 it was 20.2 / km2,while it became 12.0/ km2 in1992. The main cause of its loss was endanger from their natural enemies and human.The present area of remaining foreste where Silver Pheasants still live is only 740 km2 on the whole Island.The optimist estimate of the number of Silver Pheasant is less than 8 800. The existence of Hainan subspecies of Silver Pheasant has become endangered from vulnerable in class.Effective protection must be made promptly.