Synchrony in metapopulations at multiple time scales: theory, experiments, and field data

研究背景：在相距数百公里的地方，同一物种的种群经常以一致或部分一致的方式波动，这种现象被称为同步。例如，具有重要经济意义的英国蚜虫，因为它们是一种主要的农业害虫，在短距离内80%的同步性，在200公里的距离上50%的同步性，对于大多数蚜虫物种来说，这是一个巨大的距离。事实上，同步性很普遍，在鸟类、旅鼠、鳕鱼等鱼类、麻疹、两栖动物等人类病原体和许多其他物种中都发现了同步性。许多表现出同步性的物种具有重大的保护、经济或健康重要性。人口同步具有重要的现实意义，原因有几个。例如，同步的害虫或疾病种群需要协调一致的反应。种群数量同步的濒危物种面临着最终灭绝的危险，因为种群数量同时很少，可能会一下子全部灭绝。在许多市场上，被开发的同步化物种在很大范围内周期性地无法获得或更少获得。同步性的测量方法只用一个从1(完全同步)到-1(完全异步)的单个数字来表征两个种群之间的同步程度。这种方法很有用，但也有局限性：我们的结果表明，同步太复杂了，不能用一个数字来捕获。两个种群之间的同步可能主要发生在短时间尺度上，长时间尺度上几乎不同步；或长时间尺度上，短时间尺度上很少或不同步；或在任何范围的时间尺度上。不同地点的环境变量之间的同步性具有相同的复杂性。例如，伦敦和格拉斯哥的气温在年度时间尺度(季节性变化)和多年时间尺度(北大西洋涛动)上基本上是一起上升和下降的，但伦敦的短时间尺度(逐日)温度变化可能与格拉斯哥的相似程度要小得多。不同的同步性时间尺度具有不同的生态和灭绝风险含义，并可能对害虫的最佳控制策略具有不同的含义。此外，新的和重要的初步结果表明，作为气候变化的一部分，环境同步性的特定时间尺度结构正在发生变化，并可能影响人口同步性，从而产生灭绝风险。研究目标：我们将使用大型时空数据库、新理论和新的实验室实验来获得环境和人口同步的广泛的、特定于时间尺度的描述，并评估观察到的模式对气候变化、物种灭绝风险的影响，以及推断是什么机制导致了野外同步。应用：我们将提供关于气候变化一个新观察到的和以前未被认识到的方面的信息，以及对其对保护和虫害管理应用以及对生态理解的总体重要性的全球评估。

Research context: Populations of the same species in locations hundreds of kilometers apart often fluctuate in unison or partly in unison, a phenomenon called synchrony. For instance, British aphid species, of economic importance because they are a major agricultural pest, outbreak 80% in synchrony over short distances and 50% in synchrony over distances of 200km, a huge distance for most aphid species. In fact, synchrony is widespread, and has been detected in birds, lemmings, fish such as cod, human pathogens such as measles, amphibians, and numerous other species. Many species exhibiting synchrony are of major conservation, economic, or health importance. Population synchrony has practical importance for several reasons. For instance, synchronized pest or disease populations require a coordinated response. An endangered species whose populations are synchronized is in accentuated danger of final extinction because populations are simultaneously low and might all go extinct by chance at once. An exploited synchronized species is periodically unavailable or less available across a wide area in many markets. Synchrony has been measured with methods that characterize the degree of synchrony between two populations only by a single number from 1 (perfect synchrony) down to -1 (perfect asynchrony). This approach is useful but limited: our results show synchrony is too complex to be captured with one number. Synchrony between two populations can occur mainly on short time scales, with little to no synchrony on long time scales; or on long time scales, with little or no synchrony on short time scales; or on any range of time scales. Synchrony between environmental variables in different locations has the same complexity. For instance, temperatures in London and Glasgow rise and fall largely together on annual time scales (seasonal variation) and multi-annual time scales (the North Atlantic Oscillation), but short-time-scale (day-to-day) temperature variation in London may resemble that in Glasgow much less. Different time scales of synchrony have different ecological and extinction-risk implications, and may have different implications for optimal control strategies for pests. In addition, new and important preliminary results show that the time-scale-specific structure of environmental synchrony is changing as part of climate change, and likely affects population synchrony, and thereby extinction risk. Research aims: We will use large spatio-temporal databases, new theory, and new lab experiments to obtain a broad time-scale-specific description of environmental and population synchrony, and to assess the implications of observed patterns for climate change, extinction risks, and inference of what mechanisms cause synchrony in the field. Applications: We will provide information about a newly observed and previously unrecognized aspect of climate change and a global assessment of its overarching importance for conservation and pest management applications and for ecological understanding.