ABSTRACT Background Accidental epiphytism is common among vascular plants in forest ecosystems around the globe. A frequent observation in surveys of accidental epiphytes is the occurrence of few species with high epiphytic abundance, while most co-occurring terrestrial species are rarely found as epiphytes. Aims Based on the general assumption that water is the major limiting factor for epiphytic plants, we hypothesised that differences in drought resistance of accidental epiphytes explain the difference in epiphytic abundances. Methods We exposed 16 species with different epiphytic abundance in central Europe to experimentally induced drought during germination and growth of juvenile plants. Results Drought resistance differed substantially among species but did not correlate with their epiphytic abundance, neither during germination nor during juvenile growth. Conclusions In central Europe, accidental epiphytes are usually found on moss cushions or in accumulated arboreal soil on their host tree. In such water-storing substrates, water availability might be less limiting than it is for obligate epiphytes that typically grow on bare bark, which would explain the lack of a correlation between drought resistance and epiphytic abundance of the studied species. Hence, other factors must explain the consistent differences in epiphytic abundance, e.g. dispersal traits and mass effect.

中文翻译：

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抗旱性不能解释偶然附生植物的附生丰度

摘要背景意外附生在全球森林生态系统中的维管植物中很常见。在偶然附生植物调查中经常观察到的现象是附生植物丰度高的物种很少，而大多数共生的陆生物种很少作为附生植物被发现。目的 基于水是附生植物的主要限制因素的一般假设，我们假设偶然附生植物抗旱性的差异解释了附生植物丰度的差异。方法我们在幼年植物的萌发和生长过程中将中欧具有不同附生丰度的 16 种植物暴露于实验诱导的干旱中。结果 不同物种之间的抗旱性差异很大，但与其附生植物丰度无关，无论是在发芽期间还是在幼年生长期间。结论 在中欧，偶然的附生植物通常出现在苔藓垫上或寄主树上堆积的树栖土壤中。在这种储水基质中，水的可用性可能比通常生长在裸树皮上的专性附生植物的限制更少，这可以解释所研究物种的抗旱性和附生植物丰度之间缺乏相关性。因此，其他因素必须解释附生植物丰度的一致差异，例如扩散性状和质量效应。与通常生长在光秃秃的树皮上的专性附生植物相比，水的可用性可能不受限制，这可以解释所研究物种的抗旱性和附生植物丰度之间缺乏相关性。因此，其他因素必须解释附生植物丰度的一致差异，例如扩散性状和质量效应。与通常生长在光秃秃的树皮上的专性附生植物相比，水的可用性可能不受限制，这可以解释所研究物种的抗旱性和附生植物丰度之间缺乏相关性。因此，其他因素必须解释附生植物丰度的一致差异，例如扩散性状和质量效应。