阿利效应—低种群密度下存活力（个体平均存活率和繁殖力）的下降—可通过若干机制潜在地作用于再引入种群。按照国际自然保护联盟（IUCN）再引入专家组的定义，再引入就是在物种的历史分布区建立再引入种群的尝试。由于再引入行动中释放个体的数量常远远低于释放地的环境容纳量，而且最初阶段均处于低密度状态，因而阿利效应有可能导致再引入计划的失败。本研究试图以陕西宁陕朱鹮（Nipponia nippon）再引入种群为研究对象，调查种群参数如种群数量及年度变化、雌性繁殖概率、雌性生产力、成体、幼体存活率以及单位个体平均增长率。分析个体适合度和个体平均增长率与种群数量或密度之间的相关关系，确定影响朱鹮再引入种群的阿利效应的产生机制、作用类型和强度。再引入种群几乎永远具有小的繁殖群体，因此我们必须考虑阿利效应对再引入种群存活、增长和扩散的潜在阻碍作用以及对再引入成功率的影响，提出阿利效应的最小化策略。

Allee effects, the reduction of vital rates at low population densities, can occur through several mechanisms, all of which potentially apply to reintroduced populations. According to the Re-introduction Specialist Group of the IUCN, a reintroduction is any attempt to establish a species in an area that was once part of its historical range, but from which it has been extirpated or become extinct. Since the number of organisms released in reintroductions is usually much lower than the site-specific carrying capacity, and the reintroduced populations are initially at low densities, hence Allee effects can potentially lead to reintroduction failure. Therefore, we would focus on the reintroduced population of the Crested Ibis (Nipponia nippon) in Ningshan County by investigating demographic parameters such as annual variation of population number, female breeding probability, female productivity, adult or juvenile survival and per capita population growth rate. We aim to determine the relationship between the fitness parameter and per capita population growth rate to ibis population size or density which could demonstrate the causing mechanisms, types and strengths of Allee effects in the ibis population. As reintroductions are almost invariably characterized by small propagule sizes, the importance of the Allee effect must be considered in order to assess its potential impact on the probability of success in reintroductions, and we must consider this potential impediment to the survival, increase, and spread of small groups of reintroduced individuals in order to propose strategies for minimizing Allee effects.