植物种子生产的时空动态及潜在结实机制是决定种群动态及群落构建的重要生态过程。种子生产大小年（Mast seeding）即多年生植物种群的种子生产在年内同步且年际间高度变异的现象，这种生产格局在大量物种中都有出现。传粉效率增加和捕食者饱食被认为是有利于mast seeding进化的两个主要的选择性压力，而气候条件则是一个直接的作用因子。

在温带森林，许多优势物种都出现mast seeding这一现象。群落水平的种子生产的时空同步性，可以使一些自身种子产量甚至都不足以满足通食捕食者的物种受益。对森林群落水平上种子生产的长期监测的缺乏，阻碍了人们了解和预测植物群落对物种特定生殖压力和气候变化的响应。因此，在全球变暖的大背景下，探究森林生态系统更新及动态，特别是生殖动态及其导致的更新格局对森林具有广泛而深远的意义。

基于此，中国科学院沈阳应用生态研究所天然林生态组博士王芸芸等，以长白山阔叶红松25公顷样地内，连续8年的野外种子收集数据为研究对象，检测了群落内20个木本植物物种八年间的种子生产的变异性和同步性，并且验证了传粉效率假说以及气象因子对种子生产的直接作用，即长白山温带阔叶红松林群落水平的种子生产动态同时决定于进化中的选择压力（传粉效率假说）和气象因子的直接作用。而捕食者饱和假说在这八年的研究中仅仅表现出微弱的作用。

研究结果以Variation and synchrony of tree species mast seeding in an old-growth temperate forest （DOI: 10.1111/jvs.12494）为题发表于Journal of Vegetation Science。该研究得到中国国家重点研究与发展计划专项（2016YFC0500301）、中科院国际合作项目（151221KYSB20130003, LFSE2014–03）、国家自然科学基金(413301057)资助。（来源：中科院沈阳应用生态研究所）

Variation and synchrony of tree species mast seeding in an old-growth temperate forest

Abstract

Questions  Mast seeding, i.e. synchronous highly variable seed production among years, occurs in many perennial plant species and across diverse plant communities. Two predominant hypotheses for mast seeding are pollination efficiency and predator satiation, with weather conditions as a proximate cause. Little consensus has been achieved regarding the relative impacts of ultimate selection and proximate weather on variation in seed production. Moreover, mast-seeding studies often focus on a single species or phylogenetically closely related species, while studies on plant communities consisting of tree species with a diversity of reproductive strategies are less common.

Location  A 25-ha Changbaishan temperate forest dynamic plot, northeast China.

Methods  We used 8 yr of seed rain data to characterize patterns and evaluate underlying selective drivers of mast seeding. We employed generalized linear mixed-effects models (GLMMs) to analyse the relationships between inter-annual variability of mast seeding and weather conditions.

Results  All 20 species in this forest community exhibited high variability in annual seed production, but the magnitude of seed production among species was generally asynchronous across years. Wind-pollinated species had higher inter-annual variation of seed production than animal-pollinated species, while species dispersed by seed predators and abiotic modes (e.g. wind and gravity) showed little variation. Species responded individually to weather conditions for both temperature and precipitation, and spring phenology in the same year as seed production had a larger effect among species than both the weather conditions of the same summer and season-long lags.

Conclusions  Our findings suggest that pollination efficiency hypothesis had a much stronger effect than predation satiation hypothesis on mast seeding, and weather conditions demonstrated the proximate role of weather drivers in producing the community-wide mast-seeding pattern. We emphasize the need to simultaneously assess drivers of mast seeding for multiple species within a plant community.

原文链接：http://onlinelibrary.wiley.com/doi/10.1111/jvs.12494/pdf