Understanding the response of variability in tree reproduction (masting) to climatic and environmental change

背景：许多树种表现出一种被称为丰产的繁殖策略，其特点是在繁殖方面多年的丰厚投资(“丰年”)和多年的低投资之间切换。值得注意的是，这种变异在树木种群内部和之间是同步的。不同的机制可以解释树木如何能够a)年复一年地改变它们的种子产量，以及b)使这种差异在个体之间同步。这些机制中的大多数直接或间接依赖于气候作为桅杆的关键调节因素，这意味着桅杆可能会对气候变化做出反应。然而，桅杆对气候变化的反应仍然非常不确定。这一点很重要，因为森林更新受到种子生产、扩散和捕食的强烈调控，影响物种组成、从干扰中恢复和适应气候变化的迁徙。这些过程都受到桅杆的影响。例如，我们最近的研究表明，当全球变暖导致种子产量增加与母猪繁殖的“崩溃”相关时，增加繁殖投资的好处主要集中在种子捕食者身上，而不是植物身上。这个例子展示了在不断变化的环境中，桅杆模式的变化对森林生态系统的功能和动态的根本重要性。目标：这个项目将建立桅杆结构对最近气候变化的响应，并预测由于持续的环境变化而导致的桅杆结构的未来变化。一个关键目标将是确定支撑不同物种肥大的不同生理机制是否会导致对环境变化的不同反应。

Background: Many tree species show a reproductive strategy known as masting, which is characterised by switching between years of bumper investment in reproduction ("mast years"), and years of low investment. Remarkably, this variation is synchronised within and across tree populations. Various mechanisms may explain how trees are able to a) vary their seed production year-to-year, and b) synchronise this variation between individuals. Most of these mechanisms rely either directly or indirectly on climate as the key regulator of masting, implying that masting may respond to changes in climate. However the response of masting to climate change remains highly uncertain. This is important because forest regeneration it strongly regulated by seed production, dispersal and predation, influencing species composition, recovery from disturbance and migration in response to climate change. These processes are all influenced by masting. For example, we have recently shown that when warming-driven increase in seed production is associated with a "breakdown" in masting, the benefits of increased investment in reproduction accrue largely in seed predators, rather than the plants. This example demonstrates how changes to masting patterns are of fundamental importance to the functioning and dynamics of forest ecosystems, including in a changing environment.Objectives: This project will establish the response of masting to recent changes in climate, and predict future changes in masting resulting from ongoing environmental change. A key objective will be establish whether the different physiological mechanisms that underpin masting in different species result in contrasting responses to environmental change.