Unveiling tipping points in long-term ecological records from Sphagnum-dominated peatlands

Unveiling past tipping points is a prerequisite for a better understanding of how individual species and entire ecosystems will respond to future climate change. Such knowledge is key for the implementation of biodiversity conservation. We identify the relationships between peatland vegetation and hydrological conditions over the past 2000 years using macrofossils, testate amoebae-based quantitative hydrological reconstructions, and Sphagnum-moss functional traits from seven Polish peatland records. Using threshold indicator taxa analysis (TITAN), we discovered that plant community composition strongly converged at a water level of c. 11.7 cm, indicating a community-level tipping-point. We identified 45 plant taxa that showed either an increase or a decrease in their relative abundance between 8 and 17 cm of water level depth. Our analysis of Sphagnum community traits further showed that Sphagnum functional diversity was remarkably stable over time despite Sphagnum species sensitivity t...

揭示过去的临界点（tipping point），是深入理解单个物种乃至整个生态系统如何响应未来气候变化的核心前提。此类认知是开展生物多样性保护工作的关键支撑。本研究基于7处波兰泥炭地的沉积记录，借助大化石（macrofossils）、基于有壳变形虫（testate amoebae）的定量水文重建结果以及泥炭藓功能性状数据，厘清了过去2000年间泥炭地植被与水文条件之间的关联机制。本研究采用阈值指示类群分析（threshold indicator taxa analysis, TITAN），发现植物群落组成在水位约11.7厘米处发生显著汇聚，揭示出群落级临界点的存在。我们共识别出45个植物类群，其相对丰度在水位深度8至17厘米的区间内呈现显著的上升或下降趋势。针对泥炭藓群落性状的进一步分析显示，尽管泥炭藓物种存在敏感性差异，但泥炭藓功能多样性在长时间尺度上始终保持显著稳定。