School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA, 5005, Australia,
Oecologia. 2014 May;175(1):417-28. doi: 10.1007/s00442-014-2902-1. Epub 2014 Feb 25.
One of the strongest generalities in invasion biology is the positive relationship between probability of establishment and the numbers of individuals introduced. Nevertheless, a number of significant questions remain regarding: (1) the relative importance of different processes during introduction (e.g., demographic, environmental, and genetic stochasticity, and Allee effects); (2) the relative effects of propagule pressure (e.g., number of introductions, size of introductions, and lag between introductions); and (3) different life history characteristics of the species themselves. Here, we adopt an individual-based simulation modeling approach to explore a range of such details in the relationship between establishment success and numbers of individuals introduced. Our models are developed for typical exotic bird introductions, for which the relationship between probability of establishment and the numbers of individuals introduced has been particularly well documented. For both short-lived and long-lived species, probability of establishment decreased across multiple introductions (compared with a single introduction of the same total size), and this decrease was greater when inbreeding depression was included. Sensitivity analyses revealed four predictors that together accounted for >95% of model performance. Of these, R 0 (the average number of daughters produced per female over her lifetime) and propagule pressure were of primary importance, while random environmental effects and inbreeding depression exerted lesser influence. Initial founder size is undoubtedly going to be important for ensuring the persistence of introduced populations. However, we found the demographic traits, which influence how introduced individuals behave, to have the greatest effect on establishment success.
生物入侵学中有一个非常重要的规律，即传入个体的数量与建立种群的可能性呈正相关。然而，在以下几个方面仍存在一些重要的问题：（1）在传入过程中不同过程的相对重要性（例如，人口统计学、环境和遗传随机性以及阿利效应）；（2）繁殖体压力的相对影响（例如，传入的数量、传入的大小以及传入之间的滞后）；（3）物种本身不同的生活史特征。在这里，我们采用基于个体的模拟建模方法来探索建立成功率与传入个体数量之间关系的一系列细节。我们的模型是为典型的外来鸟类传入而开发的，对于这些传入，建立成功率与传入个体数量之间的关系已经得到了特别充分的记录。对于短寿命和长寿命的物种，与单次引入相同的总大小相比，多次引入的建立成功率降低，而当包含近亲繁殖衰退时，这种降低更为明显。敏感性分析揭示了四个共同解释了模型性能 >95%的预测因子。其中，R 0（雌性一生中每只雌性产生的女儿数量）和繁殖体压力是最重要的因素，而随机环境效应和近亲繁殖衰退的影响较小。初始奠基者的大小无疑对于确保引入种群的持续存在是重要的。然而，我们发现，影响传入个体行为的人口统计学特征对建立成功率的影响最大。
