金眶鸻巢址选择的研究

Nest-site Selection of Charadrius dubius

2007年4～7月,采用野外直接观察和样方法在北京野鸭湖湿地自然保护区对金眶鸻(Charadrius dubius)的巢址进行了调查研究。金眶鸻于4月中上旬迁来野鸭湖,5月初开始产卵。野外共发现金眶鸻的巢45个,其中水库岸边28个,岛上17个。逐巢进行了常规测量,并对巢址及附近无巢区域的生境进行了调查。通过主成分分析和独立样本t检验,结果表明,影响金眶鸻巢址选择的主要因子依次是植被盖度、植物种类、植被密度、距水源的距离、植被高度最大值、干草比例等。这说明金眶鸻倾向于在植被物种丰富度较高、植被较高、密度和盖度较大、距水源较近的地方营巢。巢址选择除了与隐蔽、食物、水、种内竞争等有关外,还与巢的保温性能有关,而巢的隐蔽性与食物是其中的关键因素。

Nest - site selection of the Little Ringed Plover （Charadrius dubius ）was surveyed in Yeyahu Lake, Beijing Wetland Natural Reserve from April to July, 2007. Both direct observation and sampling method were used to investigate the main environment factors which affect its nest - site selection. A total of 45 nests were found ,28 of them were located along the lake bank and the other 17 on the central island. Characteristics of each nest were measured. Environment factors of nest - sites and adjacent none - nest area as contrastive samples were investigated .The results of principal component analysis for environment factors of the 45 nest - sites revealed the contributions of the first six principal components had accumulated to 81.52% , containing 13 most informative parameters. The six main factors which affected the nest - site selection most were ： plant coverage, species richness, density, distance to water, maximum height of vegetation, proportion of hay. The results suggested that refuge and food were the most important for the nest - site selection of Charadrius dubius. Results of t test of 45 nest - sites and 45 contrastive samples showed that there were significant differences in vegetation density and coverage, species richness; also the proportion of naked ground. This implied that Charadrius dubius prefer the habitat with greater species richness of vegetation, greater proportion of naked ground and lower vegetation density and coverage. Higher plant coverage density may make it difficult in finding preys and moving freely, so was a disadvantage of incubation. In Yeyahu Lake, eggs＇ incubation of Charadrius dubius mainly depended on solar energy in sunny days. If an area is too sparse, the bird would prefer the site which has many shells to nest to bewilder enemy and human. This protective strategy played a similar role with that of choosing vegetation refuge. Result of t test of 28 nest -site samples on bank and 17 on island showed ,there were distinct differences in plate density, average height, maximum height and species richness of vegetation, as well as distance from human impacts. Distance from Human impact was not the key factor of nest - site selection. Charadrius dubius were more likely to prefer sites with high plant species richness and plant coverage and density and plant height and near the water line.