秀丽高原鳅种群生存力初步分析

A Preliminary Analysis on Population Viability for Triplophysa venusta

摘要: 秀丽高原鳅是云南省鹤庆县金沙江水系的土著鱼类，是青藏高原鱼类区系的主要组成部分之一，为当地的重点保护对象。但由于金沙江流域修建水电站，加之云南连年干旱，导致其种群数量急剧减少。本文采用漩涡模型分析了其种群生存力，对该种群100年内的种群动态进行了模拟。结果显示，按照当前种群的生存状况，未来100年内秀丽高原鳅种群灭绝概率为54.8%，平均灭绝时间为61.4年，100年内至少灭绝一次。秀丽高原鳅种群对繁殖率、低龄个体的死亡率和各种原因引起的灾害事件比较敏感，它们是影响种群长期存活的关键性因素。若0~1龄个体的死亡率降低20%，或者灾害事件的发生频率或影响程度降低20%，则100年内种群的存活概率为100%。秀丽高原鳅种群对环境容纳量不敏感；环境容纳量增加50%时，种群灭绝概率未降低，仅使平均种群数量增加157尾。本文的结果表明，加强渔政管理，保护秀丽高原鳅种群的栖息繁殖场所，减少灾害事件的发生频率与影响程度，降低低龄个体的死亡率，增加性成熟个体的繁殖成功率是直接有效的管理办法。

Abstract: Triplophysa venusta is one of the indigenous fish species in Yunnan province. As one of the main components of the fish fauna in Qinghai-Tibet plateau and playing an important role in the study of fish evolution, it has become the main protective fish in Yunnan province. However, its population had decreased dramatically in recent years caused by the hydropower station constructed on the Jinsha River and the continuous drought beginning in 2009 in Yunnan province. The population viability analyses were made by the vortex model, and consequently the population dynamics within the following 100 years were also predicted in T. venusta. Our results suggested that the population had a 54.8% extinct probability in the next 100 years, with an extinct time of 61.4 years under current conditions. The female fecundity, mortality of 0 - 1 age individuals, and catastrophes were the key factor influencing the long-term population survival. The survival probability of T. venusta population could rise to 100% within the next 100 years when the current mortality of 0 - 1 age individuals decreased by 20% or the frequency and severity of catastrophes to survival decreased by 20%. The carrying capacity of the population habitats had almost no effect on the population survival, even by increasing 50% of the current carrying capacity. Altogether, our study displays that the most effective measures to protect T. venusta population from extinction are enhancing the fishery management, protecting the population habitats, diminishing the occurrence of catastrophes, cutting the mortality of 0 - 1 age individuals, and rising the fecundity of mature individuals.