A unified approach to studying animal abundance: integrating evolution, ecology and scale dependency

关于动物数量丰富的问题与生态学一样古老。答案包括“老虎很稀有，因为它们很大”和“达特福德林莺很稀有，因为它们不适合英国的气候”。这些实际上是不同问题的答案：第一个是关于不同物种的相对丰度；第二个是关于同一物种种群之间的变异。然而，这两者在根本上是联系在一起的，因为相对丰度的模式因地而异。例如，达特福德林莺在英国可能很罕见，但在法国相对常见。生物学家的目标是了解这两种类型的变异，但一直被迫孤立地考虑每一种。在我的研究中，我使用了新的工具，可以在一个框架内解决这两种问题。这是第一次有可能在同一分析中模拟许多地方多种物种的丰度变化。现在有可能比较进化和生态学的重要性，以确定哪些物种应该是常见的或稀有的，以及为什么丰度因地而异。我的研究利用了这些新方法来询问有关哺乳动物和英国蝴蝶数量的问题。哺乳动物是进行这类研究的一个极好的群体，因为它们是众所周知的，它们覆盖了整个地球，它们包括小型和大型动物，它们显示出各种各样的饮食和生活方式。蝴蝶也是研究丰度的理想群体，因为英国各地的系统记录可以追溯到20多年前。这些数据是由一个大型志愿者网络收集的，已经成为生物学中最有价值的数据集之一。在单一框架中分析大量数据意味着可以同时提出几种类型的问题。我们可以问，大型物种是否总是不太常见，还有哪些其他进化因素很重要。同时，我们可以问是否在温暖的地方比在寒冷的地方发现了更多的动物。此外，我们还可以解决更复杂的问题，比如为什么有些物种对人类干预反应良好，而另一些则反应不佳。像这样的进化和生态问题很少被放在一起讨论。最后，新方法允许我解决关于空间尺度的问题。例如，对人类敏感的局部物种是否更有可能面临全球灭绝的风险？对于在小尺度上运行的过程是否能解释大尺度上的模式，人们所知相对较少，因此这些结果应该引起广大科学家的兴趣。

Questions about the abundance of animal populations are as old as the science of ecology. Answers include 'tigers are rare because they are big' and 'Dartford warblers are rare because they are not suited to the British climate'. These are actually answers to different questions: the first is about the relative abundance of different species; the second is about variation among populations of one species. However, the two are fundamentally linked because the pattern of relative abundance varies from place to place. For example, Dartford warblers may be rare in England but are relatively common in France. Biologists aim to understand both types of variation but have been forced to consider each in isolation. In my research, I use new tools that allow both types of question to be addressed within a single framework. For the first time it is possible to model in the same analysis the variation in abundance of multiple species in many places. It is now possible to compare the importance of evolution and ecology in determining which species should be common or rare and why abundance varies from place to place. My research takes advantage of these new methods to ask questions about the abundance of mammals and British butterflies. Mammals are an excellent group on which to conduct studies of this type, because they are well known, they cover the entire globe, they include both small and large animals and they display a great variety of diets and ways of life. Butterflies are also an ideal group for studying abundance, due to the systematic records from across the UK that date back over 20 years. These data were collected by a large volunteer network and have become one of the most valuable datasets in biology. Analysing abundance data in a single framework means that it becomes possible to ask several types of questions at the same time. We can ask whether large-bodied species always less common and which other evolutionary factors are important. At the same time, we can ask whether there more animals are found in warm places compared with cold ones. Also, we can tackle more complicated issues, like why some species respond well to human intervention, whereas others respond poorly. Evolutionary and ecological questions like these have rarely been addressed together. Finally, the new approach allows me to address questions about spatial scale. For example, are species that are locally sensitive to humans more likely to be at risk of global extinction? Relatively little is known about whether processes operating at small scales can account for patterns at larger scales, so the results should be of interest to a wide group of scientists.