Conservation of gene diversities in plant populations with a mixed sexual and asexual reproduction system

方差有效大小的定义是由多个人口统计学阶段组成的种群的阶段特异性参数，有性或无性繁殖。将该方程应用于生活史复杂、在一般生境条件下以鳞茎散布进行无性繁殖的多年生草本植物赤眼蜂F.camtschatcensis的两个种群，估计其有效种群大小比（Ne/N）小于0.3，长期保护所需的种群大小大于几千。对种群统计参数和生殖参数的一些虚构组合的方程的数值计算表明，具有较高的补充率和较短的成熟个体持久性的物种或种群往往具有较大的Ne/N，因此，保持较高的遗传多样性与给定的普查大小N。通过数值计算，讨论了控制种群和繁殖变量的保种遗传效应，归纳为四点;一是幼鱼成活率的提高导致Ne/N的增加，二是加速了向高Ne/N的过渡，（较发达）阶段倾向于扩大高阶段个体的Ne/N和相对分数，第三，成年（成熟）个体的持久性较长，降低了Ne/N和幼期的比例，然而，在许多多年生草本植物中观察到的成年至幼期的退化，起到降低Ne/N的作用，而不引起阶段比例的任何变化。

The variance effective size was defined in terms of stage-specific parameters of populations which are composed of multiple demographic stages, reproducing either sexually or asexually. Applying the equations to two populations of a perennial herb species F.camtschatcensis which has a complex life cycle and reproduces asexually by dispersion of bulbs in ordinary habitat conditions, the effective to census size ratio (Ne/N) and the population size required for long-term conservation were estimated to be less than about 0.3, and larger than a few thousands, respectively. Numerical computations of the equations for some fictious combinations of the demographic and reproductive parameters revealed that species or populations with a higher recruitment rate with shorter persistence of mature individuals tend to have a large Ne/N,and consequently, maintain a higher genetic diversity with a given census size N.This trend was observed between the two populations of F.camtschatcensis surveyed. Conservation genetic effects of controlling the demographic and reproductive variables were also discussed by the numerical computations to be summarized into four points ; first, increased survival rate of juveniles causes increase in Ne/N,second, accelerated transition to higher (more developed) stages tends to enlarge Ne/N and relative fractions of individuals of higher stages, third, longer persistence of adult (mature) individuals lessens Ne/N and the fraction of juveniles, and tourth, regression of adults to juvenile stage as observed in many perennial herb species acts to decrease Ne/N without causing any change in the fractions of the stages.