长江江豚的天鹅洲故道栖息地特征研究

Study on the physical habitat characteristics of Yangtze finless porpoise in Tian-e-zhou Oxbow of Yangtze River

湖北天鹅洲故道是长江江豚的重要迁地保护地。本文利用数学模型,对天鹅洲故道内的风生流流场进行了数值模拟,并分析了天鹅洲地形特征、水动力学特征、食物资源和水质等因素与江豚微生境选择之间的关系。研究结果表明,天鹅洲故道内的江豚偏好选择具有浅滩-深槽复式断面、生境多样性较高的河段栖息;风生环流对江豚微生境的选择有一定影响。同时研究发现天鹅洲故道内水位仅能满足核心区对水位的需求,缓冲区和实验区水位保证率基本无法满足。

Tian-e-zhou Oxbow of Yangzi River is a half-manual habitat of Yangtze finless porpoise. It is the first successful case of off-site preservation of cetacean in the world. Studying the features of Tian-e-zhou oxbow would take a large benefit for selecting other off-site preservation area for Yangtze finless porpoise. This paper built a 2 dimensional model of Swan Oxbow based on DHI MIKE21 software to study the wind-driven circulation in the oxbow. The thesis discussed the flow field, speed, water depth, flux of different zone for different seasons in this oxbow. The thesis also discusses the relationship between the water quality, food, topographic conditions and the requirement of habitat of finless porpoise. The the- sis is intended to integrate the ecological behavior of finless porpoise with hydraulic situation and find the basic requirement of habitat of finless porpoise. Analyses show that the finless porpoise prefers some reaches which have riffle-pool, composite cross section and complex fluid state. The wind-driven circulation has a certain influence on the choice of habitat for finless porpoise. Analysis also shows that the water level of Oxbow could only meet the required water level of core zone. The water level of buffer zone and pilot zone cannot be guaranteed.