Question What is the impact of simulated historical tree litter removal on understorey plants and soil properties in a temperate deciduous forest? What is the role of seasonal timing of tree litter removal on understorey plants? Location Podyjí National Park, Czech Republic. Methods We conducted an experiment in a randomized complete block design of 45 plots (5 × 5 m). Each block (N = 15) consisted of one plot for each of the three treatments. Treatments consisted of (i) tree litter removal during spring, (ii) tree litter removal during autumn, or (iii) no litter removal as control treatment. These treatments were repeated for a duration of four years. In each plot we recorded the understorey plant species composition and collected soil samples prior to treatment (year 0) and in each subsequent year (years 1-4). Temporal trends in species richness were analysed using repeated measures ANOVAs. The impact of the treatments on vegetation composition over time was analysed using Principal Response Curves. Results Total species richness per plot significantly changed over time, but this was not related to treatment. Annual species richness increased significantly, but only for the autumn treatment. Annual species also showed the highest inter-annual variation. Endangered species were not affected. When compared to the control treatment, the effect of autumn raking on species composition was stronger than the effect of spring raking. Although the amount of removed nutrients substantially exceeded ambient nitrogen input, no changes in soil conditions were detected. Conclusions The season in which tree litter removal took place had a small but significant impact on the understorey vegetation, in particular affecting the germination and establishment of annual species. The large inter-annual variation in species richness calls for a long-term field experiment. The removal of nutrients via litter raking greatly exceeds atmospheric nutrient deposition, warranting a further investigation of litter raking as a potential tool for forest conservation.

中文翻译：

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模拟历史树屑耙地对中欧森林林下植被的影响

问题 模拟的历史树木凋落物清除对温带落叶林的林下植物和土壤特性有什么影响？清除树屑的季节性时机对林下植物有何作用？地点波迪吉国家公园，捷克共和国。方法 我们在 45 个样地 (5 × 5 m) 的随机完整区组设计中进行了实验。每个块（N = 15）由三个处理中的每一个的一个图组成。处理包括（i）在春季清除树屑，（ii）在秋季清除树屑，或（iii）作为对照处理不清除枯枝落叶。这些治疗重复了四年。在每个地块中，我们记录了下层植物物种组成，并在处理前（第 0 年）和随后的每一年（第 1-4 年）收集了土壤样本。使用重复测量方差分析分析物种丰富度的时间趋势。使用主响应曲线分析处理对植被组成随时间的影响。结果 每个小区的总物种丰富度随时间发生显着变化，但这与处理无关。年度物种丰富度显着增加，但仅限于秋季处理。年度物种也表现出最高的年际变化。濒危物种不受影响。与对照处理相比，秋耙对物种组成的影响强于春耙。尽管去除的养分量大大超过了环境氮的输入量，但没有检测到土壤条件的变化。结论 清除树木枯枝落物的季节对林下植被影响较小，但影响显着，特别是影响一年生植物的萌发和定植。物种丰富度的巨大年际变化需要进行长期的田间试验。通过垃圾耙清除养分大大超过了大气养分沉积，值得进一步研究垃圾耙作为森林保护的潜在工具。