ABSTRACT

Introduction

This study was carried out to investigate the population status and light regime at the occupied niche of the globally threatened liverwort Lejeunea mandonii on the Lizard Peninsula, West Cornwall, UK.

Methods

Surveys were undertaken at all locations from where the species has been known and counts made of individual-equivalents (occupied 1 m grid cells). Light loggers were used to measure the light regime across a full annual cycle at a control site and at colonies of the liverwort within deciduous woodland and heathland habitat, from which percentage shade was calculated.

Key results and conclusions

The species was refound at all eight locations at which it has been known previously. A total of 157 individual-equivalents were found and it is estimated that the real total is 189–300 individual-equivalents, with the largest populations at Bonython (64 individual-equivalents counted; 41%) and Poltesco (44 individual-equivalents counted; 28%). High illuminance (> 10,000 lux) was recorded commonly at the control site (29.5% of measurements; n = 52,560), rarely in heathland (2.6–6.6%) and never in deciduous woodland. Compared with heathland, shade in deciduous woodland is higher (annual mean = 78.4–91.1% vs 98.4–98.5%) and more consistent throughout the year. The status of the species across the Lizard Peninsula seems to be favourable, but the small size of the population and its localised occurrence mean that it will remain vulnerable.

中文翻译：

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全球受威胁地钱 Lejeunea mandonii (Steph.) Müll 的种群状况和光照状况。弗里布。位于英国蜥蜴半岛

摘要

介绍

这项研究的目的是调查英国西康沃尔郡蜥蜴半岛全球受威胁的地钱Lejeunea mandonii的种群状况和光照状况。

方法

在已知该物种的所有地点进行了调查，并对个体当量进行了计数（占据 1 m 网格单元）。使用光记录仪测量对照地点以及落叶林地和石南生境内的地钱菌落的整个年度周期的光照状况，并从中计算遮荫百分比。

主要结果和结论

该物种在之前已知的所有八个地点都被重新发现。总共发现了 157 个个体当量，估计实际总数为 189-300 个个体当量，其中数量最多的是 Bonython（计算出 64 个个体当量，占 41%）和 Poltesco（计算出 44 个个体当量，占 41%）。 28%）。在对照地点通常记录到高照度（> 10,000 lux）（测量值的 29.5%；n = 52,560)，很少出现在石南荒地 (2.6–6.6%)，也不会出现在落叶林地。与石南地相比，落叶林地的遮荫程度更高（年平均值 = 78.4–91.1% vs 98.4–98.5%），并且全年更加一致。整个蜥蜴半岛的物种状况似乎不错，但种群规模小且分布范围广，意味着它们仍将很脆弱。