Demographic compensation among populations: what is it, how does it arise and what are its implications?
Demographic compensation among populations: what is it, how does it arise and what are its implications?
复制标题
人群中的人口补偿：它是什么，它是如何产生的以及它的影响是什么？
作者：
J. Villellas;D. Doak;María B. García;W. Morris
大多数物种在其生存范围内都暴露于显著的环境梯度中，但它们的生命速率（生存、生长、繁殖和补充）并不需要对这些梯度做出相同的反应。在不同的环境中，相反的生命率趋势，一种被粗略地称为“人口补偿”的现象，可能允许物种占据更大的地理范围，并改变它们对气候变化的反应。然而，这个术语从来没有被精确定义过，也没有对多个物种的存在或强度进行过评估。在这里，我们提供了一个严格的定义，并用它来开发一个强有力的人口补偿测试。通过将测试应用于26个已发表的植物多种群人口统计研究的数据，我们表明人口补偿通常会发生。我们还通过评估最常涉及的人口过程和生命阶段来研究这种现象产生的机制。此外，我们量化了人口补偿对跨环境梯度的人口增长率变化的影响，这是物种地理范围大小的潜在重要决定因素。最后，我们讨论了人口补偿对单个种群和物种范围对时间环境变化和持续环境趋势（如气候变化）的响应的影响。
Most species are exposed to significant environmental gradients across their ranges, but vital rates (survival, growth, reproduction and recruitment) need not respond in the same direction to those gradients. Opposing vital rate trends across environments, a phenomenon that has been loosely called 'demographic compensation', may allow species to occupy larger geographical ranges and alter their responses to climate change. Yet the term has never been precisely defined, nor has its existence or strength been assessed for multiple species. Here, we provide a rigorous definition, and use it to develop a strong test for demographic compensation. By applying the test to data from 26 published, multi-population demographic studies of plants, we show that demographic compensation commonly occurs. We also investigate the mechanisms by which this phenomenon arises by assessing which demographic processes and life stages are most often involved. In addition, we quantify the effect of demographic compensation on variation in population growth rates across environmental gradients, a potentially important determinant of the size of a species' geographical range. Finally, we discuss the implications of demographic compensation for the responses of single populations and species' ranges to temporal environmental variation and to ongoing environmental trends, e.g. due to climate change.