REFUGIAL POPULATIONS AT TRAILING-EDGE RANGE MARGINS: ATTRIBUTES, SURVIVAL AND CONSERVATION

许多物种目前在过去更有利的气候条件下更广泛分布的地区作为局部的避难种群存活下来。这些物种生存在与周围地区不同的局部栖息地和/或小气候中；例如，当气候变暖时，英国的一种适应寒冷的物种可能会在当地寒冷的北向地点生存下来。在允许物种在过去的气候变化中生存下来方面，避难所一直是极其重要的，在人为气候变化下，很可能再次如此。尽管如此，支持人口避难的当地条件却鲜为人知。因此，我们对未来物种可能随着气候变化而持续存在的地点的属性(位置、生境、小气候)知之甚少。了解这些属性对于为未来的保护政策提供信息以及对物种地理分布的动态发展更深入的基本科学理解至关重要。我们将利用人为气候变化带来的机会，通过研究英国北方分布的四种蝴蝶，直接观察避难所种群的创建。蝴蝶是这个项目的理想研究物种，因为在过去40年的气候变化中，英国有很好的分布记录，而且当地的小气候和小生境条件影响到蝴蝶从出生到死亡的所有生命阶段。我们将重新调查英国自20世纪70年代以来拥有历史分布数据的地点，并在2004-05年重新调查这些地点，以确定哪些物种幸存下来，哪些物种灭绝。我们将使用包含物种环境信息的动态种群模型来确定自20世纪70年代人为气候变化开始以来种群存活的地点的当地小气候和栖息地特征。我们将通过研究其他北方无脊椎动物的气候避难所形成来检验我们蝴蝶发现的普遍性。然后，我们将使用我们的模型来预测未来气候变化对物种的影响，直到2100年，并确定避难所与英国现有保护区的位置重合的程度。拟议的工作将提供第一次调查和预测模型，促进范围内撤退物种种群持续存在的地点的属性。该项目将解决气候变化下物种范围动态的基本问题，并产生对政策制定者具有相当大实用价值的结果。它将为了解气候变化对生物多样性的影响开辟一条新的研究途径，并为在气候变化下制定有效保护战略的辩论提供具体的科学证据。

Many species currently survive as localised, refugial populations in regions where they used to be more widespread under more favourable past climatic conditions. These species survive in localised habitats and/or microclimates that are atypical of the surrounding region; for example, a cold-adapted species in Britain might survive on a locally cold, north-facing site when the climate warms. Refugia have been extremely important in allowing species to survive past climatic changes, and are likely to be so again under anthropogenic climate change. Despite this, the local conditions that support population refugia are poorly understood. Thus we have little idea of the attributes (locations, habitats, microclimates) of sites where species may persist in future as the climate changes. Understanding these attributes is vital for informing future conservation policies as well as for developing a deeper fundamental scientific understanding of the dynamics of species' geographic distributions. We will take advantage of the opportunity presented by anthropogenic climate change to observe the creation of refugial populations directly, by studying four species of northerly-distributed butterflies in Britain. Butterflies are ideal study species for this project because there are excellent distribution records in Britain over the past four decades of climate change, and because local microclimate and microhabitat conditions affect all butterfly life stages, from birth to death. We will re-survey sites in Britain for which we have historical distribution data since the 1970s, and which we re-surveyed in 2004-05, to determine where species have survived, and where they have become extinct. We will use dynamic population models that incorporate environmental information for species to identify the local microclimatic and habitat characteristics of locations where populations have survived since the onset of anthropogenic climate change in the 1970s. We will examine the generality of our butterfly findings by studying climate refugial formation in other northern invertebrates. We will then use our models to project the consequences of future climatic changes for species, to the year 2100, and determine the degree to which refugia coincide with the locations of existing protected areas in Britain.The proposed work will provide the first investigation of, and predictive models for, the attributes of locations that promote population persistence in range retreating species. The project will address fundamental questions about the dynamics of species' ranges under climate change, as well as producing results of considerable practical value for policy makers. It will open up a new avenue of research on understanding the impacts of climate change on biodiversity, and provide a concrete body of scientific evidence to inform the debate on developing effective conservation strategies under climate change.