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Spatial components of plasticity in tit phenology: responses, constraints and amelioration

山雀物候可塑性的空间成分：响应、约束和改善

基本信息

批准号：
NE/K006274/1
负责人：
Ben Sheldon
金额：
$ 75.93万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK006274%2F1
关键词：
Spatial components plasticity tit phenology

项目摘要

There are three potential ways in which organisms can respond to changing environments: (1) they may disperse, or migrate, (2) they may evolve so that they adapt to the new environment, or (3) they may produce different phenotypes - in other words display phenotypic plasticity - as the environment changes. A contemporary example relates to understanding responses of populations to climate change. Work to date suggests that, despite the three mechanisms being non-exclusive, population responses to climate change usually involve phenotypic plasticity. Hence, understanding the evolutionary forces acting on plasticity is of central importance in our understanding of viability in the face of climate change. Understanding of phenotypic plasticity and its role in adaptation to changing environments is hampered by the fact that most studies simply correlate an average phenotype for the population with a single value for the environment, most often at the level of an entire year. This only makes sense if the environmental cues to which organisms respond are very large-scale cues, varying little from the perspective of individuals within populations. However, we know that many organisms experience only a limited part of the environment, and that the environment may vary over quite small spatial scales. Despite this, we don't understand how animals balance these small- and large-scale cues. The central aim of this research is thus to determine how the spatial scale of the environment is important in understanding the evolution of phenotypic plasticity.Our model system involves reproductive behaviour in small woodland birds - great tits, breeding in Wytham Woods near Oxford - which are under strong natural selection to time their reproduction to coincide with peaks in abundance of moth caterpillars (e.g. the winter moth) that are adapted to feed on newly emerged leaves of deciduous trees. At the population level there is a good match between the timing of birds' breeding and the peak of caterpillar abundance, but there is tremendous variation within each year in the timing of these events over quite a small spatial scale. Furthermore, we have evidence that, despite a common temperature trend, different parts of the population are responding at different rates. Hence, the population level summary statistics disguise several important levels of variation.We will use long term data on breeding behaviour and fitness, together with detailed environmental data to analyse the spatial scales at which variation in bird reproductive timing can best be explained, and to test hypotheses about the influence of scale on fitness and population dynamics. We will then supplement these data with new data collected across a regular grid of locations to determine phenology of bud-burst and caterpillar abundance, and hence characterise the extent to which birds are able to match the timing of events in their environment at different scales. Because we expect multiple scales to be important, we can make the prediction that the optimal phenotype is a balance between small- and large-scale plasticity, and hence that adaptation will not be perfect at either scale in isolation. Because the environment is patchy, we can further predict that adjusting to small- as well as large-scale cues will lead to some patches having higher productivity than others; hence the spatial scale of plasticity will lead to within population variation in population dynamics. Collecting environmental data on the ground is very time-consuming, and only limited areas can be covered; therefore we will test the extent to which satellite images can be used to estimate phenology at scales that are relevant to organisms in nature. Finally, we will carry out experimental tests of whether mis-matches in phenology between birds and the environment, which have been implicated in population declines in some species, are alleviated by being in more varied environments.

生物体对环境变化的反应有三种可能的方式：（1）它们可能会扩散或迁移;（2）它们可能会进化以适应新的环境;或者（3）随着环境的变化，它们可能会产生不同的表型，换句话说，表现出表型的可塑性。当代的一个例子涉及了解人口对气候变化的反应。迄今为止的工作表明，尽管这三种机制是非排他性的，人口对气候变化的反应通常涉及表型可塑性。因此，了解作用于可塑性的进化力量对于我们理解面对气候变化的生存能力至关重要。对表型可塑性及其在适应不断变化的环境中的作用的理解受到阻碍，因为大多数研究只是将种群的平均表型与环境的单一值相关联，最常见的是全年的水平。只有当生物体所响应的环境线索是非常大规模的线索时，这才有意义，从种群中个体的角度来看，变化很小。然而，我们知道，许多生物只经历环境的有限部分，并且环境可能在相当小的空间尺度上变化。尽管如此，我们不知道动物是如何平衡这些小规模和大规模的线索。因此，本研究的中心目标是确定环境的空间尺度在理解表型可塑性的进化中是如何重要的。我们的模型系统涉及小型林地鸟类-大山雀，在牛津附近的怀瑟姆森林繁殖--它们受到强烈的自然选择，选择繁殖的时间与蛾毛虫数量的高峰相吻合（例如冬蛾），它们适应于以落叶树的新长出的叶子为食。在种群水平上，鸟类繁殖的时间和毛虫丰度的峰值之间有很好的匹配，但在相当小的空间尺度上，这些事件的时间每年都有巨大的变化。此外，我们有证据表明，尽管有共同的温度趋势，但人口的不同部分以不同的速度作出反应。因此，人口水平的汇总统计掩盖了几个重要的变异水平。我们将使用长期的数据繁殖行为和健身，连同详细的环境数据，分析的空间尺度，在鸟类繁殖时间的变化可以最好地解释，并测试假设的规模对健身和人口动态的影响。然后，我们将用在一个规则的网格位置收集的新数据来补充这些数据，以确定萌芽和毛虫丰度的物候，从而确定鸟类能够在不同尺度上匹配其环境中事件发生时间的程度。因为我们认为多个尺度是重要的，所以我们可以预测，最佳的表型是小尺度和大尺度可塑性之间的平衡，因此适应在任何一个尺度上都不是完美的。由于环境是斑块状的，我们可以进一步预测，调整到小规模以及大规模的线索将导致一些斑块具有更高的生产力比其他人，因此空间尺度的可塑性将导致人口内的变化，在人口动态。在地面收集环境数据非常耗时，而且只能覆盖有限的地区;因此，我们将测试卫星图像在多大程度上可用于估计与自然界生物相关的尺度上的物候。最后，我们将进行实验测试，以确定鸟类与环境之间的物候学不匹配是否会因处于更多样化的环境中而减轻，这种不匹配与某些物种的种群数量下降有关。