Limitation of population recovery: a stochastic approach to the case of the emperor penguin
Limitation of population recovery: a stochastic approach to the case of the emperor penguin
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种群恢复的局限性：帝企鹅案例的随机方法
DOI：
10.1111/j.1600-0706.2009.17498.x
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发表时间：
2009
期刊：
影响因子：
3.4
通讯作者：
H. Caswell
中科院分区：
文献类型：
--
作者：
S. Jenouvrier;C. Barbraud;H. Weimerskirch;H. Caswell
由于自然或人为引起的环境变化导致的大规模人口崩溃之后可能会出现恢复。人们对控制恢复的因素越来越感兴趣，希望它们可以指导种群保护和管理，以及重新引入计划后的种群恢复。南极洲阿德利岛的帝企鹅 Aptenodytes forsteri 数量在 20 世纪 70 年代中期的政权更迭期间下降了 50%，当时气候和海洋环境政权的突然变化影响了整个南大洋生态系统。此后，人口一直保持稳定，尚未恢复。为了确定限制恢复的因素，我们研究了政权转变后生存和繁殖成功率变化的后果。成虫存活率恢复到政权转变前的水平，但政权转变后平均繁殖成功率下降，繁殖成功率的方差增加。使用随机矩阵种群模型，我们发现，如果保留政权更迭之前观察到的繁殖成功率分布，帝企鹅种群将会恢复，平均恢复时间为 36 年。观察到的政权转变后育种成功率的分布使得恢复的可能性非常小。这表明繁殖成功的模式足以阻止帝企鹅种群的恢复。根据育种成功预测的种群轨迹与观察到的轨迹一致。这表明，除育种成功之外的任何因素的净影响一定很小。我们发现恢复的概率和恢复的时间取决于育种成功的均值和方差。当平均成功率较低时，繁殖成功率的增加会增加恢复的可能性，但当平均成功率较高时，则会产生相反的效果。这项研究显示了育种成功在决定长寿物种种群恢复方面的重要作用，并表明导致种群崩溃的人口统计机制可能不同于阻止种群恢复的人口统计机制。
Major population crashes due to natural or human-induced environmental changes may be followed by recoveries. There is a growing interest in the factors governing recovery, in hopes that they might guide population conservation and management, as well as population recovery following a re-introduction program. The emperor penguin Aptenodytes forsteri population in Terre Adelie, Antarctica, declined by 50% during a regime shift in the mid-1970s, when abrupt changes in climate and ocean environment regimes affected the entire Southern Ocean ecosystem. Since then the population has remained stable and has not recovered. To determine the factors limiting recovery, we examined the consequences of changes in survival and breeding success after the regime shift. Adult survival recovered to its pre-regime shift level, but the mean breeding success declined and the variance in breeding success increased after the regime shift. Using stochastic matrix population models, we found that if the distribution of breeding success observed prior to the regime shift had been retained, the emperor penguin population would have recovered, with a median time to recovery of 36 years. The observed distribution of breeding success after the regime shift makes recovery very unlikely. This indicates that the pattern of breeding success is sufficient to have prevented emperor penguin population recovery. The population trajectory predicted on the basis of breeding success agrees with the observed trajectory. This suggests that the net effect of any facors other than breeding success must be small. We found that the probability of recovery and the time to recovery depend on both the mean and variance of breeding success. Increased variance in breeding success increases the probability of recovery when mean success is low, but has the opposite effect when the mean is high. This study shows the important role of breeding success in determining population recovery for a long-lived species and demonstrates that demographic mechanisms causing population crash can be different from those preventing population recovery.