1. In a time of rapid environmental changes, identification of the effects of climate warming on charophytes (Characeae, Charophyta) will enable the optimization of conservation measures, especially for extremely rare species. Lychnothamnus barbatus is one of the rarest charophytes worldwide, which has decreased in the number of occupied sites over the last century. However, the recolonization of former sites has been observed in recent years (e.g. Lake Kuźnickie, Poland). The study aimed to analyse the effects of climatic changes and human pressure on the L. barbatus population.
2. Three 30 cm sediment cores were collected from minimum, average, and maximum depths of L. barbatus occurrence to determine the past vegetation composition. Sediment cores were dated using the radioisotopes lead-210, caesium-137, and carbon-14. A spatial analysis of the lake catchment changes during the last 120 years was also conducted.
3. The study demonstrated L. barbatus presence in Lake Kuźnickie at the beginning of the 16th century. However, a sharp increase in the proportion of this species in the vegetation community occurred in the 19th century and during climate warming at the end of the Little Ice Age. Factors that significantly influenced the present occurrence of the L. barbatus population included improvement in water quality and the oospore bank deposited in the bottom sediments.
4. This study is the first palaeoreconstruction in a modern lake dominated by L. barbatus. Based on the history of L. barbatus in Lake Kuźnickie after the end of the Little Ice Age, the positive effect of climate warming on the contemporary recovery of this charophyte is postulated.
5. The reaction of L. barbatus to climate warming appears to differ from commonly accepted scenarios for aquatic macrophytes because its recovery in the past and at present coincided with increases in air temperature. This research indicated the appropriate management and conservation practices for lakes with L. barbatus populations.

中文翻译：

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濒危物种受益于温和气候变暖的初步证据：轮藻Lychnothamnus barbatus的古湖泊学研究

1. 在环境快速变化的时代，确定气候变暖对轮藻（Characeae，Charophyta）的影响将有助于优化保护措施，尤其是对于极其稀有的物种。Lychnothamnus barbatus是世界上最稀有的轮藻之一，在上个世纪占据的地点数量有所减少。然而，近年来已经观察到旧址的重新殖民化（例如，波兰 Kuźnickie 湖）。该研究旨在分析气候变化和人类压力对L. barbatus种群的影响。
2. 从L. barbatus出现的最小、平均和最大深度收集三个 30 cm 沉积物核心，以确定过去的植被组成。沉积物岩心使用放射性同位素铅 210、铯 137 和碳 14 测年。还对过去 120 年间湖泊流域变化进行了空间分析。
3. 该研究表明，L. barbatus在 16 世纪初就存在于 Kuźnickie 湖中。然而，该物种在植被群落中的比例急剧增加发生在 19 世纪和小冰河时代末期气候变暖期间。显着影响L. barbatus种群当前出现的因素包括水质的改善和沉积在底部沉积物中的卵孢子库。
4. 这项研究是在以L. barbatus为主的现代湖泊中的第一次古建筑。根据小冰河时代结束后 Kuźnickie 湖中L. barbatus的历史，假设气候变暖对这种轮藻的当代恢复产生积极影响。
5. L. barbatus对气候变暖的反应似乎与水生大型植物普遍接受的情景不同，因为它在过去和现在的恢复与气温升高相吻合。这项研究表明了对有L. barbatus种群的湖泊的适当管理和保护措施。