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Abstract：
Functional traits respond to environmental drivers, hence evaluating trait-environment relationships across spatial environmental gradients can help to understand how multiple drivers influence plant communities. Global-change drivers such as changes in atmospheric nitrogen deposition occur worldwide, but affect community trait distributions at the local scale, where resources (e.g. light availability) and conditions (e.g. soil pH) also influence plant communities. We investigate how multiple environmental drivers affect community trait responses related to resource acquisition (plant height, specific leaf area (SLA), woodiness, and mycorrhizal status) and regeneration (seed mass, lateral spread) of European temperate deciduous forest understoreys. We sampled understorey communities and derived trait responses across spatial gradients of global-change drivers (temperature, precipitation, nitrogen deposition, and past land use), while integrating in-situ plot measurements on resources and conditions (soil type, Olsen phosphorus (P), Ellenberg soil moisture, light, litter mass, and litter quality). Among the global-change drivers, mean annual temperature strongly influenced traits related to resource acquisition. Higher temperatures were associated with taller understoreys producing leaves with lower SLA, and a higher proportional cover of woody and obligate mycorrhizal (OM) species. Communities in plots with higher Ellenberg soil moisture content had smaller seeds and lower proportional cover of woody and OM species. Finally, plots with thicker litter layers hosted taller understoreys with larger seeds and a higher proportional cover of OM species. Our findings suggest potential community shifts in temperate forest understoreys with global warming, and highlight the importance of local resources and conditions as well as global-change drivers for community trait variation.
摘要：
功能特征响应环境驱动因素，因此，评估跨空间环境梯度的性状-环境关系可以帮助理解多种驱动因素如何影响植物群落。全球变化的驱动因素，如大气氮沉降的变化，在世界范围内发生，但影响当地尺度的社区特征分布，其中资源（例如光可利用性）和条件（例如土壤pH值）也会影响植物群落。我们调查了多种环境驱动因素如何影响与资源获取相关的社区性状反应(植物高度，比叶面积（SLA），木质,和菌根状态)和再生(种子质量，侧向蔓延）欧洲温带落叶林下层。我们对底层社区进行了采样，并在全球变化驱动因素的空间梯度上得出了性状响应(温度，降水,氮沉积,和过去的土地利用)，同时整合对资源和条件(土壤类型，奥尔森磷（P），埃伦伯格土壤水分，光,垫料,和垃圾质量)。在全球变化的驱动因素中，年平均温度强烈影响与资源获取相关的性状。较高的温度与较高的下层有关，产生具有较低SLA的叶子，木质和专性菌根（OM）物种的覆盖率更高。在Ellenberg土壤水分含量较高的地块中，群落的种子较小，木质和OM物种的覆盖率较低。最后,凋落物层较厚的地块拥有较高的底层，种子较大，OM物种的覆盖率较高。我们的研究结果表明，随着全球变暖，温带森林底层的潜在社区变化，并强调当地资源和条件以及全球变化驱动因素对社区特征变异的重要性。
