Data for: Always on the tipping point – a search for signals of past societies and related peatland ecosystem critical transitions during the last 6500 years in N Poland

We explored past critical transitions in a peatland located in N Poland using a densely dated (×44 14C dates & 210Pb), high-resolution multi-proxy profile. A 6450-year record was supported by a very robust age-depth model. Changes in land use, climate change and carbon sequestration in northern Poland were investigated using a range of biotic proxies. We determined critical transitions in the development of the mire which were dependent upon extrinsic drivers. The trophic status of mire shifted several times during the last 6.5 millennia. The pattern of changes suggests that it was very sensitive to different changes in the peatland basin. We identified several factors which may have driven transitions between the bog and fen state as a response to catchment hydrology changes largely driven by human impact which overlapped with periods of climate change. Based upon microcharcoal and pollen analyses, the threshold for fire intensity was estimated to be ca 7500 particles/cm2/year-1. We discovered that this burning was also an important tipping point for the divergence between plants positively related (e.g. human indicators and Carpinus) or negatively (e.g. Quercus) to fires. This community threshold was related to ecological changes related to the emergence and fall of subsequent human communities. The first pollen grains which indicate human activities in the deposits are dated to ca 6000 cal. BP, however, almost continuous human impact started since 5000 cal. BP. Then past societies actively affected the mire’s environment. The strongest signal comes from the Neolithic (Funnel Beaker Culture, Globular Amphora Culture and Corded Ware Culture), the Bronze Age (Iwno Culture and Trzciniec Culture), the Pre-Roman (La Tène) Period and the Roman Period (Oksywie Culture and Wielbark Culture). These past societies exploited natural resources and deforested the landscape while actively using fire. We inferred a distinct human influence since ca 5000 cal. BP (the Neolithic) until the Early Middle Ages with strong evidence during the Bronze Age and Roman Period which demonstrates the high importance of the area until the transition from the tribe period to the Polish state. The peatland possibly recorded several climatic shifts at: 6k (cool-warm), 4.2k (cool), 2.6k (wet shift) and 1.5k cal. BP (the Dark Ages - cold shift), however the climate change signal

本研究依托一套高密度年代序列（共计44组碳十四测年（14C dates）与铅210测年（210Pb））的高分辨率多代用指标剖面，对波兰北部一处泥炭地（peatland）的全新世临界转变过程展开探究。该研究获得了一条时长6450年的沉积记录，其年代框架由稳健的年龄深度模型（age-depth model）支撑。研究借助多类生物代用指标（biotic proxies），探究了波兰北部的土地利用变化、气候变化与碳固存过程。本研究明确了该沼泽（mire）发育过程中受外部驱动因子调控的临界转变事件：在过去6500年间，该沼泽的营养状态曾发生多次转变，其变化模式表明其对泥炭地盆地内的各类扰动极为敏感。研究识别出多类驱动贫营养沼泽（bog）与富营养沼泽（fen）状态转换的因子，这些转换是对流域水文变化的响应，而流域水文变化主要受人类活动影响，且与气候变化时段重合。基于微炭屑（microcharcoal）与孢粉分析（pollen analyses）结果，本研究估算出火灾强度阈值约为7500颗粒/平方厘米/年。研究发现，该区域的火灾活动同时也是植物群落分化的关键临界点：部分植物（如人类活动指示物种与鹅耳枥属（Carpinus））与火灾呈正相关，而另一部分（如栎属（Quercus））则与火灾呈负相关。该植物群落临界点与后续人类社群兴衰引发的生态变化密切相关。沉积记录中最早指示人类活动的孢粉可追溯至约6000校准年前（cal. BP），但持续的人类影响则始于约5000校准年前。此后，过往人类社群持续对该沼泽的生态环境产生主动干扰。人类活动的最强信号出现在新石器时代（漏斗杯文化、圆腹彩陶文化与绳纹陶文化）、青铜时代（伊沃诺文化与特奇涅茨文化）、前罗马时期（拉坦诺时期）以及罗马时期（奥克西维文化与维尔巴克文化）。这些过往人类社群开发自然资源、改造森林景观，并主动用火开展生产活动。本研究推断，约5000校准年前（新石器时代）至中世纪早期，该区域一直受到显著的人类活动影响，其中青铜时代与罗马时期的证据最为充分，表明该区域在部落联盟向波兰国家过渡的阶段始终具有重要地位。该泥炭地可能记录了以下几次气候转变事件：6000校准年前（冷转暖）、4200校准年前（降温）、2600校准年前（湿度升高）以及1500校准年前（黑暗时代冷期，降温），但气候变化信号