Data from: Cryptic inbreeding depression in a growing population of a long-lived species

Genetic effects are often overlooked in endangered species monitoring, and populations showing positive growth are often assumed to be secure. However, the continued reproductive success of a few individuals may mask issues such as inbreeding depression, especially in long-lived species. Here, we test for inbreeding depression in little spotted kiwi (Apteryx owenii) by comparing a population founded with two birds to one founded with 40 birds, both from the same source population and both showing positive population growth. We used a combination of microsatellite genotypes, nest observations and modelling to examine the consequences of assessing population viability exclusively via population growth. We demonstrate (i) significantly lower hatching success despite significantly higher reproductive effort in the population with two founders; (ii) positive growth in the population with two founders is mainly driven by ongoing chick production of the founding pair; and (iii) a substantial genetic load in the population founded with two birds (10–15 diploid lethal equivalents). Our results illustrate that substantial, cryptic inbreeding depression may still be present when a population is growing, especially in long-lived species with overlapping generations.濒危物种监测工作中，遗传效应常被忽视，种群增长为正的种群往往被默认处于安全状态；然而少数个体持续的繁殖成功可能掩盖近交衰退（inbreeding depression）等遗传问题，在长寿物种中这一现象尤为显著。本研究以小斑几维鸟（Apteryx owenii）为研究对象，通过对比两个同起源种群——分别由2只和40只个体奠基且均呈现正种群增长——来检测近交衰退效应；研究结合微卫星基因型（microsatellite genotypes）检测、巢观测与模型模拟，探究仅通过种群增长评估种群生存力的潜在后果。结果表明：（1）尽管奠基者仅2只的种群繁殖投入显著更高，但其孵化成功率却显著偏低；（2）该奠基种群的正增长主要源于原配对个体持续产出雏鸟；（3）奠基者仅2只的种群存在显著遗传负荷，其携带的二倍体致死当量（diploid lethal equivalents）为10~15个。本研究结果证实，即便种群处于增长状态，仍可能存在大量隐蔽的近交衰退效应，这一现象在世代重叠的长寿物种中尤为突出。