Alatalo Juha M, Jägerbrand Annika K, Chen Shengbin, Molau Ulf
Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, PO Box 2713, Doha, Qatar.
Calluna AB, Hästholmsvägen 28, 131?30 Nacka, Sweden.
Ann Bot. 2017 Jul 1;120(1):159-170. doi: 10.1093/aob/mcx053.
Climate change is expected to have major impacts on high alpine and arctic ecosystems in the future, but empirical data on the impact of long-term warming on lichen diversity and richness are sparse. This study report the effects of 18 years of ambient and experimental warming on lichens and vascular plant cover in two alpine plant communities, a dry heath with sparse canopy cover (54 %) and a mesic meadow with a more developed (67 %) canopy cover, in sub-arctic Sweden.
The effects of long-term passive experimental warming using open top chambers (OTCs) on lichens and total vascular plant cover, and the impact of plant cover on lichen community parameters, were analysed.
Between 1993 and 2013, mean annual temperature increased about 2 °C. Both site and experimental warming had a significant effect on cover, species richness, effective number of species evenness of lichens, and total plant canopy cover. Lichen cover increased in the heath under ambient conditions, and remained more stable under experimental warming. The negative effect on species richness and effective number of species was driven by a decrease in lichens under experimental warming in the meadow. Lichen cover, species richness, effective number of species evenness were negatively correlated with plant canopy cover. There was a significant negative impact on one species and a non-significant tendency of lower abundance of the most common species in response to experimental warming.
The results from the long-term warming study imply that arctic and high alpine lichen communities are likely to be negatively affected by climate change and an increase in plant canopy cover. Both biotic and abiotic factors are thus important for future impacts of climate change on lichens.
预计气候变化未来将对高海拔和北极生态系统产生重大影响，但关于长期变暖对 lichen 多样性和丰富度影响的实证数据却很稀少。本研究报告了在瑞典亚北极地区的两个高山植物群落中，18 年的环境变暖与实验性变暖对 lichen 和维管植物覆盖度的影响，这两个群落分别是树冠覆盖稀疏（54%）的干燥石南荒原和树冠覆盖更发达（67%）的中生草甸。
分析了使用开顶式气室（OTC）进行长期被动实验性变暖对 lichen 和维管植物总覆盖度的影响，以及植物覆盖度对 lichen 群落参数的影响。
1993 年至 2013 年期间，年均温度升高了约 2°C。地点和实验性变暖对 lichen 的覆盖度、物种丰富度、有效物种数、均匀度以及植物树冠总覆盖度均有显著影响。在环境条件下，石南荒原中的 lichen 覆盖度增加，在实验性变暖条件下保持更稳定。在草甸中，实验性变暖导致 lichen 减少，从而对物种丰富度和有效物种数产生负面影响。lichen 覆盖度、物种丰富度、有效物种数均匀度与植物树冠覆盖度呈负相关。实验性变暖对一个物种有显著负面影响，对最常见物种的丰度有降低的非显著趋势。
长期变暖研究结果表明，北极和高海拔 lichen 群落可能会受到气候变化和植物树冠覆盖度增加的负面影响。因此，生物和非生物因素对于气候变化未来对 lichen 的影响都很重要。
