崇明东部滩涂珍禽越冬栖息地的自然环境因素

THE NATURAL ENVIRONMENTAL CONTROL FACTORS OF THE HABITAT OF CERTAIN RARE BIRDS WINTERING AT THE EASTERN BEACH OF CHONGMING ISLAND, SHANGHAI

珍禽越冬栖息地多年保持稳定不变的原因,除由生境所能提供的食料——海三棱藨草的地下球茎所决定外,根本原因在于地下球茎最发育的滩段,是在海三棱藨草群落的外带,是低潮滩向高潮滩演替过程中淤涨速率最快的滩段。其潮汐水动力条件有利于淤涨;大型潮沟的限定,更保护和保证了滩涂淤涨速率。这多种自然环境因素,决定了珍禽对越冬栖息地的选择。

Through the field investigation, it showed that the wintering habitat of certain rare birds remain Steadily and unchangeably for many years because of favorable food condition, i. e. the subterraneous corms of Scirpus mariqueter. In the outer zone of S. mariqueter community, the subterraneous corms grow well and the output is wealthy. The wintering habitat if located in the outer zone of the intertidal flat where sedimentary rate of mud and silt if higher, and between two large tidal channels sedimentary rate reached the highest. The activity of tidal current is favoured for deposition of mud and silt on this beach. These are the natural environmental factors advantaged for rare birds wintering.