Climate change is altering patterns of seed production worldwide [1, 2, 3, 4], but the potential for evolutionary responses to these changes is poorly understood. Masting (synchronous, annually variable seed production by plant populations) is selectively beneficial through economies of scale that decrease the cost of reproduction per surviving offspring [5, 6, 7]. Masting is particularly widespread in temperate trees [8, 9] impacting food webs, macronutrient cycling, carbon storage, and human disease risk [10, 11, 12], so understanding its response to climate change is important. Here, we analyze inter-individual variability in plant reproductive patterns and two economies of scale—predator satiation and pollination efficiency—and document how natural selection acting upon them favors masting. Four decades of observations for European beech (Fagus sylvatica) show that predator satiation and pollination efficiency select for individuals with higher inter-annual variability of reproduction and higher reproductive synchrony between individuals. This result confirms the long-standing theory that masting, a population-level phenomenon, is generated by selection on individuals. Furthermore, recent climate-driven increases in mean seed production have increased selection pressure from seed predators but not from pollination efficiency. Natural selection is thus acting to restore the fitness benefits of masting, which have previously decreased under a warming climate [13]. However, selection will likely take far longer (centuries) than climate warming (decades), so in the short-term, tree reproduction will be reduced because masting has become less effective at satiating seed predators. Over the long-term, evolutionary responses to climate change could potentially increase inter-annual variability of seed production of masting species.

气候变化正在改变全世界种子生产的模式 [1, 2, 3, 4]，但对这些变化的进化反应潜力知之甚少。Masting（植物种群同步、每年可变的种子生产）通过规模经济有选择性地获益，降低每个幸存后代的繁殖成本 [5, 6, 7]。Masting 在温带树木中尤为普遍 [8, 9]，影响食物网、常量营养素循环、碳储存和人类疾病风险 [10, 11, 12]，因此了解其对气候变化的反应很重要。在这里，我们分析了植物繁殖模式和两种规模经济——捕食者饱食和授粉效率——的个体间变异性，并记录了自然选择对它们的作用如何有利于发芽。欧洲山毛榉的四个十年观察（山毛榉）表明捕食者的饱食度和授粉效率选择具有较高的年际繁殖变异性和个体之间较高的繁殖同步性的个体。这一结果证实了长期存在的理论，即 masting 是一种种群水平的现象，是通过对个体的选择产生的。此外，最近气候驱动的平均种子产量增加增加了种子捕食者的选择压力，但没有增加授粉效率。因此，自然选择的作用是恢复桅杆的健康益处，这在以前在气候变暖的情况下已经减少 [13]。然而，选择可能需要比气候变暖（几十年）更长的时间（几个世纪），因此在短期内，树木繁殖将减少，因为长杆在满足种子捕食者方面变得不那么有效。从长远来看，