长江江豚种群生存力分析及其对保护区规划的启示

Analysis of Population Viability of Yangtze River Finless Porpoise and Its Enlightenment to Protected Area Planning

在现有条件下,构建1个初始种群数量为20头、环境容纳量为100头的保护区,长江江豚种群在未来100年的内禀增长率为-0.0536~0.1378,周限增长率为0.9478~1.1477,净增殖率为0.6602~2.5870,雌性平均世代为6.90~7.75a,雄性平均世代为7.77~8.52a,平均现存种群数量为14.21~30.09头,平均种群数量为1.51~19.10头,平均遗传多样性为0.4820~0.4919,灭绝概率为0.3704~1.0000,平均首次灭绝时间为19.1~59.5 a。只有当保护区环境容纳量达到160头时,在未来100年内长江江豚种群的存活概率才能达到95%,此时的MVP为38~41头。进一步的模拟分析发现环境容纳量相对不限的条件下,最小的MVP为22头,而满足MVP为22头的最小环境容纳量为366头;同时得到了在不同环境容纳量水域长江江豚种群的MVP,并对最小可存活种群下长江江豚未来100年的生存动态进行了分析。基于上述研究结果,提出了相关的长江江豚种群保护和管理建议。

A protected area with an initial population of 20 heads and an environmental capacity of 100 heads was constructed under the existing conditions.The intrinsic rate of increase of the Yangtze finless porpoise population in the next 100 years will be-0.0536~0.1378.The increment rate would be 0.9478~1.1477.The net reproductive rate will be 0.6602~2.5870.The average generation of females will be 6.90 to 7.75 a,the average generation of males will be 7.77~8.52 a.The average number of existing populations will be 14.21~30.09.The average population will be 1.51~19.10.The average genetic diversity will be 0.4820~0.4919.The extinction probability will be 0.3704~1.0000,and the average first extinction time(year)will be 19.1~59.5 a.When the environmental capacity reaches 160 heads,the survival probability of Yangtze finless porpoise in the next 100 years will reach more than 95%.At the time,the MVP will be 38~41 heads.Further simulations show that the minimum MVP will be 22 heads under the condition that the environmental capacity is relatively unlimited,and the minimum environmental capacity for a MVP of 22 will be 366 heads.At the same time,MVP of Yangtze finless porpoise population in different environmental capacity waters will be obtained.The survival dynamics of the Yangtze River finless porpoise in the next 100 years under the MVP was analyzed.Relevant protection and management recommendations were proposed based on the research results.