钳嘴鹳觅食生境选择及食物特征分析

Foraging habitat selection and food characteristic analysis of Asian open-bill stork

为了探究钳嘴鹳(Anastomus oscitans)觅食生境选择的主导因子并分析其食物特征,以觅食的钳嘴鹳个体为中心设置1m×1m的方格作为觅食样方,累计测量了96个觅食样方和80个对照样方的生境因子.结果表明,觅食样方的水面积、最大水深和可见水生动物的平均值均大于对照样方的平均值;而最高植物高度对照样方大于觅食样方.对钳嘴鹳觅食生境的12个因子的特征值进行主成分分析表明,钳嘴鹳偏爱在植被低矮、食物丰富的湿地生境中与其他水鸟混群觅食.在钳嘴鹳觅食区域内、外分别采集长、宽、高均为10cm的泥块作为样方泥块和对照泥块,累计记录了70个样方泥块和26个对照泥块中的水生动物,样方泥块水生动物的种类平均值与对照泥块水生动物的种类平均值无显著差异,但样方泥块水生动物的数量平均值显著高于对照泥块水生动物的数量平均值.样方泥块水生动物体长(s)在s<5mm和5mm≤s<10mm水平的数量显著高于对照泥块水生动物的数量,水生动物其他体长水平在两类泥块之间数量上无显著差异.该研究对钳嘴鹳物种保护具有重要意义.

In order to explore the dominant factors in foraging habitat and analyze the food characteristics of Asian open-bill stork(Tachybaptus ruficollis),foraging habitat sample was set 1 m×1 m centered foraging stork individuals.Totally,habitat factors from 96 foraging samples and 80 control samples were surveyed.The results indicated that means from water area,deepest water and visible aquatic animal are higher in foraging habitat sample than those in control sample;but maximum plant height is higher in control sample than in foraging habitat sample.Principal component analysis on twelve habitat factors from foraging site showed that Asian open-bill stork prefers to probe prey in moist substrate with low plant and with plentiful food,and mix with other waterbirds.Mud pills with 10 cm long,10 cm wide and 10 cm deep dug within and outside of foraging site are defined as mud pill samples and references,respectively.Totally,aquatic animals from 70 mud pill samples and 26 references are recorded.No significant differences present in species richness of aquatic animals between mud pill sample and reference,but higher in number of aquatic animals in mud pill sample than in reference.The number with body size(s)of aquatic animal at levels of s<5 mm and 5 mm≤s<10 mm are higher in sample than those in reference,but no significant differences on aquatic animal number show at other levels between the two types of mud pill.This study can be benefit for Asian open-bill stork conservation.