Species-specific activation time-lags can explain habitat restrictions in hydrophilic lichens.
Species-specific activation time-lags can explain habitat restrictions in hydrophilic lichens.
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DOI：
10.1111/j.1365-3040.2009.02111.x
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发表时间：
2010-05
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影响因子：
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通讯作者：
Marlene Lidén;Anna V Jonsson Cabrajić;M. Ottosson‐Löfvenius;K. Palmqvist;T. Lundmark
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文献类型：
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作者：
Marlene Lidén;Anna V Jonsson Cabrajić;M. Ottosson‐Löfvenius;K. Palmqvist;T. Lundmark
在四种亲水地衣和一种通用地衣中测量了与水或潮湿空气水合后的光系统 II (PSII) 激活，以检验缓慢激活可能解释前一组地衣栖息地限制的假设。对于亲水物种，Lobaria amplissima 和 Platismatia Norvegica 的激活在 4 小时后几乎完成，而只有 c. Bryoria bicolor 和 Usnea longissima 为 50%。多才多艺的青花瞬间被激活。使用分离雨水和潮湿空气这两个水源的动态模型研究了这对地衣田表现的影响。使用来自 12 个溪流微生境的物种特定特征和气候数据进行了模型模拟。对于 U. longissima 来说，缓慢的 PSII 激活可能会将实现的光合作用减少五倍。 Bryoria bicolor 几乎受到同样严重的影响，而 P.norvegica 则表现出适度的减少。即使在不利的小气候下，Lobaria amplissima 也表现出更长的实际活动期，这可能是因为具有更高的抗失水能力。靠近溪流和湍流水的存在都对缓慢激活的物种之间的实际活动产生积极影响，这与观察到的亲水物种的分布模式相一致。因此，这里提出的结果可以部分解释观察到的稀有亲水地衣的栖息地限制。
Photosystem II (PSII) activation after hydration with water or humid air was measured in four hydrophilic and a generalist lichen to test the hypothesis that slow activation might explain habitat restriction in the former group. For the hydrophilic species, activation was after 4 h nearly completed in Lobaria amplissima and Platismatia norvegica, while only c. 50% for Bryoria bicolor and Usnea longissima. The generalist Platismatia glauca was activated instantaneously. The effect of this on lichen field performance was investigated using a dynamic model separating the two water sources rain and humid air. Model simulations were made using the species-specific characteristics and climate data from 12 stream microhabitats. For U. longissima, slow PSII activation could reduce realized photosynthesis by a factor of five. Bryoria bicolor was almost as severely affected, while P. norvegica displayed moderate reductions. Lobaria amplissima displayed longer realized activity periods even in unfavourable microclimates, possibly because of a higher water loss resistance. Both close proximity to streams and presence of turbulent water had a positive impact on realized activity among the slowly activated species, coinciding with observed distribution patterns of hydrophilic species. The results presented here may thus partly explain observed habitat restrictions of rare hydrophilic lichens.