Abstract. Forest steppes are dynamic ecosystems, highly susceptible to changes in climate, disturbances and land use. Here we examine the Holocene history of the European forest steppe ecotone in the lower Danube Plain to better understand its sensitivity to climate fluctuations, fire and human impact, and the timing of its transition into a cultural forest steppe. We used multi-proxy analyses (pollen, n-alkanes, coprophilous fungi, charcoal and geochemistry) of a 6000-year sequence from Lake Oltina (southeastern Romania) combined with a REVEALS (Regional Estimates of Vegetation Abundance from Large Sites) model of quantitative vegetation cover. We found a greater tree cover, composed of xerothermic (Carpinus orientalis and Quercus) and temperate (Carpinus betulus, Tilia, Ulmus and Fraxinus) tree taxa, between 6000 and 2500 cal yr BP. Maximum tree cover ( ∼  50 %), dominated by C. orientalis occurred between 4200 and 2500 cal yr BP at a time of wetter climatic conditions and moderate fire activity. Compared to other European forest steppe areas, the dominance of C. orientalis represents the most distinct feature of the woodland's composition at this time. Tree loss was underway by 2500 yr BP (Iron Age), with the REVEALS model indicating a fall to ∼  20 % tree cover from the Late Holocene forest maximum, linked to clearance for agriculture, while climate conditions remained wet. Biomass burning increased markedly at 2500 cal yr BP, suggesting that fire was regularly used as a management tool until 1000 cal yr BP when woody vegetation became scarce. A sparse tree cover, with only weak signs of forest recovery, then became a permanent characteristic of the lower Danube Plain, highlighting more or less continuous anthropogenic pressure. The timing of anthropogenic ecosystem transformation here (2500 cal yr BP) falls between that in central-eastern (between 3700 and 3000 cal yr BP) and eastern (after 2000 cal yr BP) Europe. Our study is the first quantitative land cover estimate at the forest steppe ecotone in southeastern Europe spanning 6000 years. It provides critical empirical evidence that, at a broad spatial scale, the present-day forest steppe and woodlands reflect the potential natural vegetation in this region under current climate conditions. However, the extent of tree cover and its composition have been neither stable in time nor shaped solely by the climate. Consequently, vegetation change must be seen as dynamic and reflecting wider changes in environmental conditions including natural disturbances and human impact.

摘要。森林草原是动态的生态系统，极易受到气候变化，干扰和土地利用的影响。在这里，我们研究了多瑙河平原下游欧洲森林草原过渡带的全新世历史，以更好地了解其对气候波动，火灾和人类影响的敏感性，以及过渡到文化森林草原的时间。我们对来自奥尔蒂纳湖（罗马尼亚东南部）的6000年序列进行了多代理分析（花粉，正构烷烃，共生真菌，木炭和地球化学），并结合了定量模型（大区域植被丰度的区域估算）植被覆盖。我们发现了一个更大的树木覆盖物，由干热的（Carpinus Orientalis和Quercus）和温带树（Carpinus betulus，Tilia，Ulmus和Fraxinus）树种，在6,000到2500 cal yr BP之间。在潮湿的气候条件下，中等火力活动时，最大的树木覆盖率（约50％）由东方念珠菌占主导地位，发生在4200至2500 cal yr BP之间。与其他欧洲森林草原地区相比，东方梭菌占主导地位代表了当时林地组成最鲜明的特征。在2500年BP（铁器时代）之前，树木的损失正在发生，REVEALS模型表明，晚全新世森林的最高覆盖率使树木覆盖率下降了约20％，这与农业清除相关，而气候条件仍然潮湿。在2500 cal yr BP时，生物量燃烧显着增加，这表明直到1000 yr BP时木本植物稀缺时，才经常使用火作为管理工具。稀疏的树木覆盖，只有很少的森林恢复迹象，然后成为多瑙河平原下游的永久特征，凸显出或多或少的持续人为压力。这里的人为生态系统转变的时间（2500 cal BP）介于欧洲中东部（3700到3000 cal BP之间）和东欧（2000 BP之后）之间。我们的研究是东南欧森林草原过渡带6000年以来的首次定量土地覆盖估计。它提供了重要的经验证据，表明在目前的气候条件下，当今的森林草原和林地在广阔的空间范围内反映了该地区潜在的自然植被。然而，树木的覆盖范围及其组成既未及时稳定，也未完全受气候影响。因此，必须将植被变化视为动态变化，并反映环境条件的更广泛变化，包括自然干扰和人类影响。我们的研究是东南欧森林草原过渡带6000年以来的首次定量土地覆盖估计。它提供了重要的经验证据，表明在目前的气候条件下，当今的森林草原和林地在广阔的空间范围内反映了该地区潜在的自然植被。然而，树木的覆盖范围及其组成既未及时稳定，也未完全受气候影响。因此，必须将植被变化视为动态变化，并反映环境条件的更广泛变化，包括自然干扰和人类影响。我们的研究是东南欧森林草原过渡带6000年以来的首次定量土地覆盖估计。它提供了重要的经验证据，表明在目前的气候条件下，当今的森林草原和林地在广阔的空间范围内反映了该地区潜在的自然植被。然而，树木的覆盖范围及其组成既未及时稳定，也未完全受气候影响。因此，必须将植被变化视为动态变化，并反映环境条件的更广泛变化，包括自然干扰和人类影响。当前的森林草原和林地反映了当前气候条件下该地区潜在的自然植被。然而，树木的覆盖范围及其组成既未及时稳定，也未完全受气候影响。因此，必须将植被变化视为动态变化，并反映环境条件的更广泛变化，包括自然干扰和人类影响。当前的森林草原和林地反映了当前气候条件下该地区潜在的自然植被。然而，树木的覆盖范围及其组成既未及时稳定，也未完全受气候影响。因此，必须将植被变化视为动态变化，并反映环境条件的更广泛变化，包括自然干扰和人类影响。