In this study we aim to investigate millennial-scale dynamics of Isoëtes, a type of macrophyte well adapted to oligotrophic and clear-water lakes. Despite its wide distribution during the Early Holocene, nowadays Isoëtes is considered as vulnerable or critically endangered in many Central European countries. Using a multi-proxy palaeoecological reconstruction involving Isoëtes micro- and megaspores, pollen, plant macrofossils, macro-charcoal, diatoms and chironomids from four lakes (Prášilské jezero, Plešné jezero, Černé jezero, Rachelsee) located in the Bohemian Forest Ecosystem mountain region in Central Europe, we reconstruct Isoëtes dynamics and discuss how local environmental factors impacted its distribution and abundance during the Holocene. Our results show regionally concurrent patterns of Isoëtes colonisation across all lakes beginning 10,300–9300 cal yr BP, and substantially declining around 6400 cal yr BP. Results from Prášilské jezero imply that Isoëtes decline and collapse in this lake reflect gradual dystrophication that led to the browning of lake water. This is evidenced by a shift in diatom assemblages towards more acidophilous taxa dominated by Asterionella ralfsii and by a decrease in total chironomid abundance and taxa sensitive to low oxygen levels. Dystrophication of Prášilské jezero was linked with the immigration of the late-successional tree taxa (Picea abies and later Fagus sylvatica and Abies alba), peatland expansion, and decreasing fire activity. Multi-site comparison of pollen records suggest that these vegetation-related environmental changes were common for the whole region. Our study demonstrates the sensitivity of Isoëtes to millennial-scale natural environmental changes within the surrounding lake catchment.

在这项研究中，我们旨在研究Isoëtes的千禧年尺度动力学，Isoëtes是一种非常适合贫营养和清水湖泊的大型植物。尽管在全新世早期分布广泛，但如今在许多中欧国家，伊索埃特人都被视为脆弱或极度濒危。使用波西米亚森林生态系统地区的四个湖泊（Práilsilskéjezero，Plešnéjezero，Černéjezero，Rachelsee）的多湖古生物重建，包括Isoëtes的微孢子和大孢子，花粉，植物大型化石，大型木炭，硅藻和奇虫，中欧，我们重建伊索特动态，并讨论全新世期间局部环境因素如何影响其分布和丰度。我们的结果表明，从10300-9300年BP开始，所有湖泊中Isoëtes殖民地的区域并发模式开始，而在6400年BP附近则大幅下降。Prášilskéjezero的结果表明，该湖的Isoëtes下降和倒塌反映了逐渐的营养不良，导致湖水泛黄。这可以通过硅藻组合向更偏酸性的分类群的转变来证明，该分类群以拉夫链球菌为主，对低氧水平敏感的总手足虫的丰度和分类群减少。Prášilskéjezero的营养不良与后期成功树类群的迁徙有关（云杉，后来水青冈和银冷杉），泥炭地扩张，降低火活动。花粉记录的多站点比较表明，这些与植被相关的环境变化在整个地区都是常见的。我们的研究表明，伊索埃特斯对周围湖泊流域内千禧年规模的自然环境变化敏感。