Yukon ice patches: Bryophyte generation from ancient ice-entombed assemblages

In Southwestern Yukon, ice patches have shown substantial retreat since the Little Ice Age (1600–1900 AD) in response to warming trends. These ice patches support unique alpine wetlands that have formed habitats for diverse flora and fauna over millennia. With ice retreat, pristine bryophyte populations are exposed beneath accumulated ancient dung. Given that bryophytes have been shown to survive extreme conditions including ice entombment and can regenerate from viable cells, emergent ice margin bryophyte and dung samples from the Granger and Gladstone ice patches were assayed for regrowth potential under growth chamber conditions. Diaspore (spore/fragment) generation of species found in the original subfossil material was indicated in 68 percent of assays, emphasizing the cyclical establishment of ancient ice patch vegetation. One of the oldest samples, dating 4036 calibrated years BP from the Gladstone ice patch margin, showed remarkable bryophyte generation from diaspores in dung. These Yukon ice patches form reservoirs of cryopreserved biota and have a critical role in maintaining alpine diversity, which provides summer refuge for caribou and other alpine fauna. Ice margin fluctuations, which bury and release populations through time, are part of a complex revegetation sequence in alpine regions that has followed deglaciation.在育空地区西南部，自小冰期（Little Ice Age，公元1600–1900年）以来，冰斑因气候变暖趋势出现了显著消退。这些冰斑孕育了独特的高山湿地，数千年来为多样的动植物提供了栖息环境。随着冰斑消退，堆积的古老粪便下方暴露出原生苔藓植物（bryophyte）种群。鉴于苔藓植物已被证实可在包括冰封在内的极端环境中存活，并可通过活细胞实现再生，研究人员对格兰杰冰斑与格拉德斯通冰斑的冰缘出露苔藓植物及粪便样本，开展了生长箱条件下的再生潜力检测。在68%的检测中，原始亚化石材料中发现的物种产生了传播体（Diaspore，即孢子/片段），这一结果凸显了古冰斑植被的周期性重建过程。其中一枚来自格拉德斯通冰斑冰缘、经校准距今4036年的古老样本，展现出从粪便传播体中萌发苔藓植物的卓越能力。这些育空冰斑是低温保存生物群落的储存库，在维持高山生物多样性方面发挥着关键作用，并为驯鹿及其他高山动物提供了夏季庇护所。冰缘的周期性波动会随时间掩埋并释放种群，这是冰川消退后高山地区复杂植被重建序列的重要组成部分。