Riding the elevator to extinction: Disjunct arctic-alpine plants of open habitats decline as their more competitive neighbours expand
Riding the elevator to extinction: Disjunct arctic-alpine plants of open habitats decline as their more competitive neighbours expand
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DOI：
10.1016/j.biocon.2022.109620
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发表时间：
2022-07
影响因子：
5.9
通讯作者：
S. Watts;D. Mardon;Catherine Mercer;D. Watson;Helen Cole;R. Shaw;A. Jump
中科院分区：
文献类型：
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作者：
S. Watts;D. Mardon;Catherine Mercer;D. Watson;Helen Cole;R. Shaw;A. Jump
在气候变暖的情况下，预计北极高山物种将向高海拔和高纬度地区迁移。在其物种分布的极限地带的山上持续存在的间断性植物种群可能具有降低的迁移能力，因此提供了气候变化影响的特别敏感的指示。苏格兰山区的植物群具有国际意义，因为它包含了气候遗迹的种群，这些种群在地理上是孤立的，位于其全球范围的后边缘。我们使用了一个独特的长期监测数据集，记录了苏格兰高地一个山区前哨站的植被变化，以确定过去30年来10种稀有植物物种的不同种群趋势。自20世纪90年代中期以来，三种北极高山专家（Sagina nivalis，Sabulina rubella和Saxifraga cernua）遭受了超过50%的人口规模的严重下降，并在其最低海拔位置被灭绝。这些物种正在经历海拔范围的收缩，雪漆姑草现在在英国被认为是濒危物种。它们开阔的砾石雪床栖息地受到植被侵蚀、山体滑坡和岩崩的影响。所有研究物种的种群变化也与海拔高度显著相关。种群规模稳定或不断增加的物种出现在海拔较低的地方，较高，对植被稀疏的栖息地依赖较少。这些结果可以在嗜热化，生物同质化，山区绿化和积雪减少的广泛趋势的背景下。我们的工作表明，间断的低纬度北极高山植物种群已经位于最大的当地海拔梯度可能面临“山顶灭绝”，与区域生物多样性的保护的影响。
Major displacement of arctic-alpine species towards higher elevations and latitudes is anticipated under climate warming. Disjunct plant populations persisting on mountains at the limits of their species' distributions may have a reduced capacity for migration, and therefore offer a particularly sensitive indication of climate change effects. The flora of Scotland's mountains is of international significance because it contains populations of climate relicts which are isolated geographically and located at the rear edge of their global range. We used a unique long-term monitoring dataset recording vegetation change at a mountain outpost site in the Scottish Highlands to identify divergent population trends in ten rare plant species over the last 30 years. Three arctic-alpine specialists (Sagina nivalis, Sabulina rubella and Saxifraga cernua) have suffered severe declines of over 50 % of their population size since the mid-1990s, and have been extirpated at their lowest altitude locations. These species are undergoing elevational range contractions andSagina nivalisis now considered Endangered in Britain. Their open, gravelly snowbed habitats have been affected by vegetation encroachment, landslip and rockfalls. Population changes across all species studied were also significantly related to altitude. Species with stable or increasing population sizes occur at lower altitudes, are taller and have less reliance on sparsely vegetated habitats. These results can be contextualised within broad trends of thermophilization, biotic homogenization, mountain greening and snow cover declines. Our work demonstrates that disjunct low-latitude arctic-alpine plant populations already situated at maximum local elevational gradients could face “mountaintop extinction”, with implications for the conservation of regional biodiversity.