ABSTRACT Introduction. This study investigated the ecology of two boreal-montane bryophytes, the saxicolous moss Bartramia halleriana and the epixylic liverwort Crossocalyx hellerianus, at the edge of their ranges, in oceanic deciduous woodland in Wales. Methods. The study site comprises two adjoining woodlands, Allt Penyrhiw-iar (canopy trees ca. 100 yr old) and Allt Rhyd Groes (ca. 200 yr), Carmarthenshire, UK. The distribution and abundance of B. halleriana and C. hellerianus was surveyed, relevés sampled to record habitat and community composition, and sporophyte frequency and stage of development measured. Light climate of B. halleriana was investigated via hemispherical photography, and abundance of large rotten logs used as a measure of habitat quality for C. hellerianus. Results. Four subpopulations of B. halleriana occured, comprising 21 individual-equivalents (occupied 1 m grid cells), all on mildly base-rich mudstone of north-facing rockfaces, with very little direct solar radiation and a diverse assemblage of bryophytes. Sporophytes were scarce. A total of 143 individual-equivalents (occupied logs or trees) of C. hellerianus was recorded, an exceptional population in Wales. Most of the population was within Allt Rhyd Groes, where large rotten logs were much more abundant due to greater woodland age. The liverwort mainly occupied the sides of decorticated rotten logs, amongst a sparse community composed mainly of other small liverworts and Cladonia lichens. Neither sporophytes nor perianths were found on C. hellerianus specimens. Conclusion. Further research could usefully focus on the description and measurement of favourable habitat conditions for each species and associated physiological tolerances to inform conservation decisions for both species.

中文翻译：

---

威尔士海洋落叶林中 Bartramia halleriana 和 Crossocalyx hellerianus 的生态方面

摘要介绍。本研究调查了威尔士海洋落叶林中两种北山地苔藓植物的生态学，即石舌苔藓 Bartramia halleriana 和外生苔藓 Crossocalyx hellerianus，位于它们分布范围的边缘。方法。研究地点包括两个毗邻的林地，Allt Penyrhiw-iar（树龄约 100 年的树冠）和英国卡马森郡的 Allt Rhyd Groes（约 200 年）。调查了 B.halleriana 和 C. hellerianus 的分布和丰度，对相关样本进行采样以记录栖息地和群落组成，并测量孢子体频率和发育阶段。通过半球摄影研究了 B.halleriana 的光照气候，并将大量腐烂的原木用作 C. hellerianus 栖息地质量的衡量标准。结果。出现了 B.halleriana 的四个亚群，包括 21 个单独的等价物（占据 1 m 网格单元），全部位于朝北岩面的轻度富含碱的泥岩上，太阳直接辐射很少，苔藓植物种类繁多。孢子体稀少。总共记录了 143 个个体等效物（被占用的原木或树木）C. hellerianus，这是威尔士的一个特殊种群。大多数人口都在 Allt Rhyd Groes 内，由于林地年龄较大，那里的大型腐烂原木更加丰富。地衣主要占据去皮腐木的两侧，在一个主要由其他小型地衣和克拉多尼亚地衣组成的稀疏群落中。在 C. hellerianus 标本上既没有发现孢子体也没有发现花被。结论。