Terricolous lichens are relevant associates of biological soil crusts in arid and semiarid environments. Dunes are ecosystems of high conservation interest, because of their unique, vulnerable and threatened features. The function of lichens is affected by the changing seasons and different microhabitat conditions. At the same time, inland dunes are less investigated areas from the terricolous lichens point of view. We explored the effect of seasonal variation and different micro-environmental conditions (aspect) on the metabolic activity of five terricolous lichen species, representing various growth forms, in temperate semiarid grasslands. Populations of Cladonia foliacea, C. furcata, C. pyxidata group, Diploschistes muscorum and Thalloidima physaroides were investigated. Thalli sampled from the south-west and north-east facing microhabitats were studied by chlorophyll fluorescence analysis for 2 years. The present study aims to understand how changing climate (during the year) and aspect affect photosynthetic activity and photoprotection. Microclimatic data were also continuously recorded to reveal the background of the difference between microhabitat types. As a result, the air temperature, photosynthetically active radiation, soil temperature and vapour pressure deficit were significantly higher on south-west than on north-east facing microsites, where relative humidity and water content of soil proved to be considerably higher. Higher photosynthetic activity, as well as a higher level of photoprotection, was detected in lichens from north-east-oriented microsites compared with south-west populations. In addition, the difference between sun and shade populations varied seasonally. Since a species-specific response to both aspect and season was detected, we propose to investigate more than one species of different growth forms, to reveal the response of lichens to the changing environment in space and time.

中文翻译：

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沙丘生活的光明与阴暗面：地衣对季节变化的光合作用是特定物种的

地衣是干旱和半干旱环境中生物土壤结皮的相关物质。沙丘由于具有独特，脆弱和受威胁的特征而成为具有高度保护意义的生态系统。地衣的功能受季节变化和不同的微生境条件的影响。同时，从地衣角度来看，内陆沙丘的研究较少。我们探索了季节性变化和不同的微环境条件（方面）对温带半干旱草原上五种代表各种生长形式的地衣类苔藓植物代谢活性的影响。的种群石蕊foliacea，C. furcata，C. pyxidata基，Diploschistes muscorum和拟南芥被调查了。通过叶绿素荧光分析研究了西南和东北面临的微生境的塔利（Thalli），历时2年。本研究旨在了解气候变化（一年中的变化）和方面如何影响光合作用和光保护作用。还连续记录了微气候数据，以揭示微生境类型之间差异的背景。结果，西南部的空气温度，光合有效辐射，土壤温度和蒸气压赤字明显高于东北部的微型站点，后者的相对湿度和土壤含水量被证明要高得多。更高的光合作用活性和更高水平的光保护能力，与西北地区的人口相比，在东北方向的微型地点发现了地衣。此外，日照和阴暗种群之间的差异随季节变化。由于检测到物种对季节和季节的响应，我们建议研究不止一种不同生长形式的物种，以揭示地衣对时空变化环境的响应。