Willoughby Janna R, Christie Mark R
Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054; and Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN.
J Hered. 2017 Jul 1;108(5):583-587. doi: 10.1093/jhered/esx046.
Supplementation programs, which release captive-born individuals into the wild, are commonly used to demographically bolster declining populations. In order to evaluate the effectiveness of these programs, the reproductive success of captive-born individuals released into the wild is often compared to the reproductive success of wild-born individuals in the recipient population (relative reproductive success, RRS). However, if there are heritable reductions in fitness associated with captive breeding, gene flow from captive-born individuals into the wild population can reduce the fitness of the wild population. Here, we show that when captive ancestry in the wild population reduces mean population fitness, estimates of RRS are upwardly biased, meaning that the relative fitness of captive-born individuals is over-estimated. Furthermore, the magnitude of this bias increases with the length of time that a supplementation program has been releasing captive-born individuals. This phenomenon has long-term conservation impacts since management decisions regarding the design of a supplementation program and the number of individuals to release can be based, at least in part, on RRS estimates. Therefore, we urge caution in the interpretation of relative fitness measures when the captive ancestry of the wild population cannot be precisely measured.
放归圈养繁殖个体到野外的补充计划通常用于在人口统计学上支持数量下降的种群。为了评估这些计划的有效性，常常将放归野外的圈养繁殖个体的繁殖成功率与接受种群中野生繁殖个体的繁殖成功率进行比较（相对繁殖成功率，RRS）。然而，如果存在与圈养繁殖相关的可遗传的适应性降低，圈养繁殖个体向野生种群的基因流动会降低野生种群的适应性。在此，我们表明，当野生种群中的圈养祖先降低了平均种群适应性时，RRS的估计会向上偏差，这意味着圈养繁殖个体的相对适应性被高估了。此外，这种偏差的程度会随着补充计划放归圈养繁殖个体的时间长度而增加。这种现象具有长期的保护影响，因为关于补充计划设计和放归个体数量的管理决策至少部分可能基于RRS估计。因此，当无法精确测量野生种群的圈养祖先时，我们敦促在解释相对适应性测量时要谨慎。
