NI: MAST-NET: masting responses to climate change and impacts on ecosystems

大多数植物不产生定期的年度种子作物，而是在种子作物丰收年（称为“丰收年”）和种子产量低的年份之间切换。有趣的是，这些大丰收同时发生在彼此相邻的植物中，并且同步可以延伸数百公里。例如，我们之前已经证明，在1976年，1992年，1995年和最近的2011年，西欧（包括英国，德国，法国和波兰）的山毛榉树都在同一年产生了大量的种子作物。有趣的是，1992年和1995年也是同一地区云杉林松果生产的丰收年，这种高度可变的种子生产是生态系统中的一个重要过程。生产种子是成功培育下一代植物的关键一步。桅杆对植物是有益的，因为在种子作物丰收的年份，种子捕食者不能消耗所有可用的种子，这确保了一些种子存活到明年春天发芽。在受野火、风暴和人类伐木等干扰影响的生态系统中，下一个种子丰收年的时机对植物的再生能力也至关重要。然而，桅杆的重要性超出了植物。森林树木中的丰收种子作物代表着食物资源的脉动，并导致小型哺乳动物（如田鼠和老鼠）和食种子鸟类（如啄木鸟和大山雀）的种群激增。连续几年的低种子作物最终可能导致人口崩溃。这些小动物的繁荣和萧条周期对生态系统产生了进一步的影响。对人类最重要的影响之一是对蜱虫数量的影响，蜱虫数量会随着宿主动物的数量而波动。蜱虫是莱姆病病原体的宿主，研究表明，人类的莱姆病感染率在包括山毛榉和橡树在内的林木种子丰收两年后达到顶峰。然而，桅杆不仅在自然生态系统中很重要。许多水果和坚果作物来自“桅杆”物种。在农业中，这种现象通常被称为“轮作”。在英国种植的水果，包括苹果和樱桃，在作物大小上表现出这种特征性的年度变化，这导致农民的年度作物产量变化。它在许多其他有商业价值的物种中也很重要，包括橄榄，杏仁和阿月浑子。由于这些原因，我们需要能够准确地预测“桅杆”物种中的种子作物。这些信息对于管理依赖于桅杆物种的自然生态系统和农业系统是必要的。此外，预测种子作物丰收将使我们能够预测由动物饲养媒介（如莱姆）携带的传染病的高风险年份。一个重要的问题是如何在桅杆物种的种子生产将在未来的气候变化的变化。该项目旨在作为实现这些目标的第一个关键步骤。它将建立一个国际研究人员网络，建立必要的数据集，以了解种子作物丰收的原因，并预测主要物种的种子产量。我们将把热带地区的数据与北方森林的数据结合起来，以了解不同物种之间的桅杆变化，并将利用网络成员进行的长期监测来了解种子产量如何随时间变化，以及是什么引发了种子丰收年。我们还将搜索档案和科学文献中的有用数据：在以前的一个项目中，我们发现了18世纪世纪林业工作者收集的种子作物的有用数据，表明在某些物种中，有可能发展很长的种子生产记录。我们将在该项目中建立的数据集将作为未来研究的跳板，包括与公共卫生，栖息地管理和农业相关的项目，利用广泛的网络专业知识。

Most plants do not produce regular annual seed crops, but switch between years of bumper seed crops (known as "mast years") and years with low seed production. Intriguingly, these bumper crops occur simultaneously in plants living alongside each other, and synchronisation can extend across hundreds of kilometres. For example, we have previously shown that in 1976, 1992, 1995 and most recently in 2011, beech trees across Western Europe (including the UK, Germany, France and Poland) all produced heavy seed crops in the same year. Interestingly, 1992 and 1995 were also bumper years for pine-cone production in spruce forests in the same region.This highly variable production of seeds is an important process in ecosystems. Producing seeds is a key step towards successfully establishing the next generation of plants. Masting is beneficial for plants because in years of bumper seed crops, seed predators cannot consume all the available seeds, which ensures that some survive to germinate the next spring. In ecosystems that are influenced by disturbance such as wildfires, windstorms and logging by humans, the timing of the next bumper seed year is also crucial to the ability of plants to regenerate. However, the importance of masting extends beyond plants. Bumper seed crops in forest trees represent a pulse of food resources, and cause population booms in small mammals (e.g. voles and mice) and seed-eating birds (e.g. woodpeckers and great tits). Low seed crops in sequential following years can eventually result in population crashes. These boom-and-bust cycles of small animals have further impacts on ecosystems. One of the most important for humans is the effect on tick numbers, which fluctuate in response to the number of host animals. Ticks act as a host for the Lyme disease pathogen, and research has shown that Lyme infection rates in humans peak two years after bumper seed crops in forest trees, including beech and oak. Masting is not just important in natural ecosystems, however. Many fruit and nut crops come from "masting" species. In agriculture, this phenomenon is usually known as "alternate cropping". Fruits grown in the UK, including apples and cherries, show this characteristic year-to-year variation in crop size, which causes variation in annual crop yield for farmers. It is also important in many other commercially valuable species, including olives, almonds and pistachios. For these reasons, we need to be able to predict seed crops in "masting" species accurately. This information is necessary for the management of natural ecosystems and agricultural systems that rely on masting species. Furthermore, predicting bumper seed crops will allow us to forecast years of high risk from infectious diseases carried by animal feeding vectors, such as Lyme. An important question is how seed production in masting species will change in the future with changes in climate. This project is designed as the first crucial step to achieving these objectives. It will establish an international network of researchers to build the datasets necessary to understand the causes of bumper seed crops, and to predict seed production in masting species. We will draw together data from the tropics with data from boreal forests to understand how masting varies between species, and will use long-term monitoring conducted by members of the network to understand how seed production varies over time, and what triggers bumper seed years. We will also search archives and scientific literature for useful data: in a previous project we found useful data on seed crops collected by 18th century foresters, demonstrating that in some species, there is potential to develop very long records of seed production. The datasets that we will build in this project will then act as a spring-board for future research, including projects linked to public health, habitat management, and agriculture, taking advantage of the wide range of network expertise.