利用稳定同位素技术分析青海湖优势水鸟的营养级结构  

Analysis on Trophic Structure of Main Waterbirds in Qinghai Lake Based on Stable Isotopic Technology

作　　者：杨月琴[1] 易现峰[1] 李宁[2] 

机构地区：[1]河南科技大学农学院,河南洛阳471000 [2]青海大学农牧学院,青海西宁810007

出　　处：《Zoological Research》2009年第4期418-422,共5页动物学研究（英文）

基　　金：国家自然科学基金资助项目(30700078);河南省高校科技创新人才计划资助项目(2008HASTIT003)

摘　　要：2008年4—6月对青海湖湖区主要水鸟的稳定性碳和氮同位素组成进行了测定,依据营养级间的同位素富集效应以及营养级计算模型(TL水鸟=3+(δ15N水鸟-1.78-δ15N浮游动物)/3.8),分析并确定了主要水鸟在生态系统中的营养级层次。相对于水生动物而言,水鸟的δ15N具有明显的富集效应,而δ13C不显著。依据稳定性同位素的营养富集效应模型,通过普通鸬鹚(Phalacrocorax carbo)和青海湖裸鲤(Gymnocypris przewalskii)间δ15N的比对,确定了该系统中排泄尿酸的水鸟稳定性氮同位素的富集因子为1.78‰。利用δ15N建立了稳定同位素比值与营养层次的关系。浮游植物、浮游动物、青海钩虾(Gammarus suifunensis)、裸鲤和水鸟的营养层次分别为1.64—2.06、2.35—2.83、2.63、3.64—4.20和3.35—4.93。由于湖区普通鸬鹚、渔鸥(Larus ichthyaetus)、棕头鸥(Larus brunnicephalus)和凤头■鷉(Podiceps cristatus)的食物来源主要是湖体中的裸鲤,由模型计算得到它们处在最高的营养级阶层;赤麻鸭(Tadorna ferruginea)、普通燕鸥(Sterna hirundo)和红脚鹬(Tringa totanus)属杂食性水鸟,营养阶层居中;而斑头雁(Anser indicus)由于主要以水生和陆生植物为食,处在最低的营养阶层。裸鲤资源未来的状况必将影响到普通鸬鹚、渔鸥、棕头鸥,以及凤头■鷉的生长、繁衍以及整个系统的群落结构和稳定性。Stable carbon and nitrogen isotopes were measured to analyze trophic level of main waterbirds in Qinghai Lake in May-June, 2008, based on the model of isotopic enrichment and the fractionation factor. Our results indicated that 815N was significantly enriched in the muscle of waterbirds, but δ^13C showed no obvious variation. We obtained a fractionation factor between Gymnocypris przewalskii and Phalacrocorax carbo, i.e., 1.78‰ . Phytoplankton, zooplankton, Gammarus suifunensis, G. przewalsldi and waterbirds were estimated at the trophic levels of 1.64-2.06, 2.35-2.83, 2.63, 3.64-4.20 and 3.35-4.93 respectively. P. carbo, Larus ichthyaetus, Larus brunnicephalus and Podiceps cristatus occupied the highest trophic level due to their primary feeding on G przewalskii. However, Tadornaferruginea, Sterna hirundo, and Tringa totanus occupied the relatively high trophic levels. Anser indicus, mainly relying on plant materials as their food supply, was at the lowest trophic level. Our results predicted that the future resource situation of G przewalskii would have great influence on the growth, reproduction and community structure of main waterbirds, especially for P carbos, L. ichthyaetus, L. brunnicephalus and P. cristatus, consequently on the stability and diversity of the whole ecosystem.

关 键 词：水鸟 营养级 裸鲤 稳定性同位素 青海湖 

分 类 号：Q958[生物学—动物学]