Anthropogenic interventions lead to various direct and indirect impacts on natural ecosystems that are often hindered by natural long-term variability, and thus their detection and evaluation remain challenging. Ecological systems are strongly affected by climate variations that typically exhibit long-term correlations capable of imitating or hindering external trends in finite-time observations, thus complicating their detection and correct attribution to either anthropogenic interventions or natural variability. Here we focus on the quantitative assessment of the alterations in the tree-ring width (TRW) of four tree species in response to the changes in the soil water regime following a drainage experiment in a dwarf-shrub type peatland forest. We consider the long-term effects of the intervention, focusing on two characteristic quantities: the durations of clusters when significant discrepancies with relevant controls could be observed in every single consecutive year, and relative trends in the data reflecting long-term, gradual changes in the ecosystem. By extrapolating pre-drainage TRW dynamics and adjusting for recent climate variations using a multivariate model, we simulate surrogate data series that act as additional controls for the post-drainage time period. By comparing the long-term dynamics of the observational TRW data series against both natural and surrogate controls over several decades following the drainage experiment, we evaluate long-term alterations and gradual trends in the tree growth dynamics and reassess the statistical significance of these effects, taking into account long-term correlations in the natural TRW variations. Our results also indicate pronounced alterations in the drought stress response characterized by significant negative trends in the tree growth dynamics following the 2010 heatwave and associated flash drought in the drained area, while no similar effect could be observed in the undrained area, indicating that the increased productivity of the forest ecosystem following the drainage likely comes at the cost of its reduced drought stress resilience.

中文翻译：

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通过长期树木年轮观测检测和评估人为对天然森林生态系统的影响

人为干预会对自然生态系统产生各种直接和间接影响，而这些影响往往受到自然长期变化的阻碍，因此其检测和评估仍然具有挑战性。生态系统受到气候变化的强烈影响，气候变化通常表现出长期相关性，能够模仿或阻碍有限时间观测中的外部趋势，从而使它们的检测和正确归因于人为干预或自然变异变得复杂。在这里，我们重点定量评估四种树种树轮宽度（TRW）的变化，以响应矮灌木型泥炭地森林排水实验后土壤水情的变化。我们考虑干预措施的长期影响，重点关注两个特征量：连续每一年都可以观察到与相关控制存在显着差异的集群持续时间，以及反映长期、逐渐变化的数据相对趋势。生态系统。通过推断排水前 TRW 动态并使用多元模型调整最近的气候变化，我们模拟了替代数据系列，作为排水后时间段的额外控制。通过将排水实验后几十年来观测 TRW 数据系列的长期动态与自然和替代对照进行比较，我们评估了树木生长动态的长期变化和逐渐趋势，并重新评估了这些影响的统计显着性，考虑自然 TRW 变化的长期相关性。我们的结果还表明，干旱胁迫反应发生了显着变化，其特征是 2010 年热浪和相关的排水地区突发干旱之后，树木生长动态呈显着负趋势，而在未排水地区没有观察到类似的影响，这表明树木生长动态的显着负趋势。排水后森林生态系统的生产力可能会降低其干旱胁迫恢复能力。