Integrating ecological dynamics, population genetics and landscape structure in a theoretical study of range shifting.

预测物种如何应对气候变化是当今生物学家面临的最大挑战之一。我们希望能够预测一个物种是否能够在其目前的范围内适应不断变化的气候条件，或者是否能够在气候变得适宜时迁移到新的地区。英国蝴蝶的证据表明，随着气候变暖，一些物种已经向北迁移，而另一些物种似乎没有那么快做出反应。为什么不同的物种会有不同的行为？有许多可能的原因，其中很少包括在模型中，对未来的物种分布进行预测。大多数预测未来物种分布的模型都是孤立地考虑一个物种，并使用气候包络方法--基本上它们建立了一个物种今天所处的气候条件，并预测该物种将在未来任何气候条件下出现。这种方法提供了一个很好的起点，但它忽略了几个可能极其重要的生物过程。比如有些物种可能不善于扩散，可能无法像气候变化那样迅速地改变它们的分布范围。物种之间很可能存在相互作用;蝴蝶可能有很好的传播能力，但如果它的食物植物没有，那么食物植物的范围转移可能会受到限制。进化过程可能也很重要，这正是本书要研究的。现有的生态模型将被扩展，以便纳入遗传和进化过程。最初，我们将介绍中性遗传多样性-这是替代基因，不修改生物体的健身将存在于不同的个人。我们将研究在气候变化期间，由于物种改变其分布，种群内的中性遗传多样性程度如何变化。我们还将介绍对当地环境条件的适应，并进行模拟实验，看看它如何改变物种的能力，以跟上变化的步伐。一些物种已经被观察到进化，使它们能够更快地改变它们的范围。例如，一些蝴蝶和蟋蟀在向北穿越英国时，传播能力有所增强。我们将使用我们的模型框架来研究在气候变化期间其他特征可能会如何演变。

Predicting how species will respond to climate change is one of the greatest challenges facing biologists today. We want to be able to predict whether a species will be able to adapt within its current range to changing climatic conditions, or whether it will be able to move to new regions as they become climatically suitable. Evidence for British butterflies suggests that some species are already moving northwards as the climate warms, while others appear not to be responding as fast. Why might different species behave differently? There are many possible reasons, and few of these are currently included in models that make predictions regarding the future distribution of species. Most models that make predictions regarding future species distributions consider one species in isolation and use a climate envelope approach - essentially they establish the climatic conditions occupied by a species today and predict that the species will occur wherever that climate is found in the future. This method provides a good starting point, but it ignores several biological processes that may be extremely important. For example. some species may be poor at dispersing and may not be able to alter their range as rapidly as the climate change. There are likely to be interactions between species; a butterfly may have very good dispersal abilities but if its food plant doesn't, then the range shifting of the food plant may impose a limitation. Evolutionary processes may also be important, and it is these that this work will investigate. An existing ecological model will be extended so that incorporates genetic and evolutionary processes. Initially we will introduce neutral genetic diversity - that is alternate genes that do not modify an organisms fitness will be present within different individuals. We will look to see how the degree of neutral genetic diversity within a population changes during a period of climate change due to species changing their distributions. We will also introduce adaptation to local environmental conditions, and run simulation experiments to see how it modifies a species ability to keep pace with the change. Some species are already being observed to evolve such that they are able to change their ranges more rapidly. For example, some butterflies and crickets have involved increased dispersal ability as they move northwards through Britain. We will use our model framework to investigate how other characteristics might be expected to evolve during a period of climate change.