ABSTRACT Introduction. Pallavicinia lyellii is recognised as being of principal importance for conservation in England and is threatened with extinction in Europe. The aims of this study were to investigate the current status, conservation and ecology of the species in S Hampshire, a key region for the plant. Methods. All recent and historic locations for Pallavicinia lyellii in S Hampshire were searched and information collected on distribution, abundance and ecology. Results. Pallavicinia lyellii was re-found at three sites. It is almost certainly extinct at two sites and may have been lost from a third. Whilst few colonies were sterile, most comprised a single sex. Colonies with both male and female plants were confined to Cadnam Bog, which supported 49 (91%) of the colonies found. Overall, female shoots occurred at 41 (76%) colonies and males at 26 (48%), producing a female sex bias (1.6:1). All colonies occur in boggy woodland, mostly on the sides of low mounds of damp, acidic, peaty soil developed, due to poaching by ponies and cattle, at the base of trees, usually I. aquifolium. The community mainly comprises a species-poor mix of acidophilous mosses and liverworts, most frequently Mnium hornum, Pseudotaxiphyllum elegans and Leucobryum juniperoideum. Conclusions. Cadnam Bog appears to support the largest sexually reproducing population of Pallavicinia lyellii in England. The site is specially protected, actively managed with consideration to P. lyellii and seemingly in favourable condition for the plant. Research is needed to quantify canopy shade favoured by the plant and assess implications for woodland management. Future monitoring should include re-survey of populations every 3 yr.

中文翻译：

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Pallavicinia lyellii (Hook.) Carruth 的现状、保护和生态。在英格兰的一个关键地区

摘要介绍。Pallavicinia lyellii 在英国被认为是保护的重要物种，在欧洲面临灭绝的威胁。本研究的目的是调查该植物在 S 汉普郡（S Hampshire）的现状、保护和生态。方法。搜索了南汉普郡 Pallavicinia lyellii 的所有最近和历史位置，并收集了有关分布、丰度和生态的信息。结果。Pallavicinia lyellii 在三个地点被重新发现。它几乎可以肯定在两个地点灭绝，并且可能已经从第三个地点消失了。虽然少数菌落是不育的，但大多数包含单一性别。具有雄性和雌性植物的菌落被限制在 Cadnam Bog，它支持 49 (91%) 发现的菌落。全面的，雌性枝条出现在 41 (76%) 个菌落，雄性枝条出现在 26 (48%) 个，产生雌性性别偏见 (1.6:1)。所有菌落都出现在沼泽林地中，主要是在低矮的潮湿、酸性、泥炭土丘的两侧，由于小马和牛的偷猎，在树木的底部，通常是 I. aquifolium。该群落主要包括嗜酸苔藓和苔类的物种贫乏混合物，最常见的是 Mnium hornum、Pseudotaxiphyllum elegans 和 Leucobryum juniperoideum。结论。Cadnam Bog 似乎支持英格兰最大的有性繁殖种群 Pallavicinia lyellii。该场地受到特别保护，积极管理，考虑到 P. lyellii 和似乎对植物有利的条件。需要研究来量化植物喜欢的树冠遮荫并评估对林地管理的影响。