伶仃洋中华白海豚自珠三角城市扩张以来的种群衰退

POPULATION REDUCTION OF THE CHINESE WHITE DOLPHINS IN LINGDING BAY SINCE THE RAPID URBANIZATION OF THE PEARL RIVER DELTA

  • 摘要: 栖息于伶仃洋海域的中华白海豚是全球受人类活动影响最为严重的鲸类群体之一。自20世纪90年代始, 已采用样线调查法、静态生命表、捕获-再捕获法等技术手段对该群体开展多项独立研究。尽管一般认为该群体存在衰退趋势, 但是否已经衰退、衰退幅度有多大等问题一直存在较大争议。尚不明了的种群动力学情况已成为伶仃洋中华白海豚灭绝风险评估、保育资源配置及保护行动计划制定的掣肘。文章整理了近20年来伶仃洋中华白海豚种群动力学相关信息(种群大小、种群丰度、年衰退速度等), 探讨调查方案设计对种群动力学研究的影响, 并进一步讨论不同结果的生态学含义、合理性和可比性。通过不同时期的有效动力学信息进行对比, 伶仃洋的中华白海豚在1998—2015年间经历了47.7%的种群衰退; 年衰退幅度由早期的2.2%增长至6.3%。由于身处高度城市化的河口环境, 中华白海豚的种群延续和人类活动冲突难以避免。文章通过回溯伶仃洋中华白海豚的动力学发展轨迹, 强调保护行动的迫切性和种群动态监测的必要性。

     

    Abstract: The Chinese white dolphins (CWD) from the Lingding Bay (LB) are known as one of the most anthropogenically impacted cetacean populations in the world. Since the 1900s, multiple independent research have been conducted on this population using different techniques such as line transect survey, static life table analysis, and capture-recapture modeling. Though it was generally accepted that the LB Chinese white dolphins were highly susceptible to population reduction, there has been a long debate about their current population condition. The uncertainty in demography data hinders accurate extinction risk assessment, effective allocation of conservation resource, and development of efficient conservation strategies. Here, we summarize the demographic information on LB Chinese white dolphins in the past two decades (including estimates of population size, abundance, and annual declining rate), to assess the impact of survey design on the study outcomes, interpret the ecological significance of demographic estimates, and evaluate the robustness and comparability of these estimates. By comparing the representative demographic parameters obtained at different periods, we showed that the LB Chinese white dolphins have experienced a 47.7% reduction in 1998—2015, with the annual declining rate of population has accelerated from 2.2% at the beginning to 6.3% in recent years. Given the extensive urbanization of their estuarine habitat, conflict between dolphins’ persistence and human development appears unavoidable. Through reconstructing the demographic trajectory of LB Chinese white dolphins, we emphasize the urgency of conservation action and the importance of long-term monitoring program.

     

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