ABSTRACT

Introduction.

Ditrichum cornubicum is one of the world's rarest bryophytes and is undergoing a long-term decline as its habitat is gradually lost to vegetation succession in derelict mining areas. This study investigates short-term changes in abundance of the species at two sites in Cornwall (UK), including within trial management plots where turf-stripping occurred in September 2015.

Methods.

A detailed survey of D. cornubicum was undertaken in January 2020, and locations recorded using high accuracy GPS.

Results.

The species has declined dramatically in trial management plots since January 2018, illustrated by a 93% loss in occupied 0.1 m grid cells. Outside trial management plots, such a decline did not occur over the same period.

Conclusions.

Within trial management plots, D. cornubicum underwent an initial dramatic increase soon after turf-stripping in September 2015, quickly followed by a rapid decline. Initial colonisation likely arose from germination of rhizoidal gemmae in the diaspore bank, exposed by turf-stripping. The subsequent decline is at least partly due to competitive exclusion by other colonists of exposed mine spoil, especially Ceratodon purpureus, and perhaps also changes in chemistry at the spoil surface, for example due to leaching. The life-strategy of D. cornubicum is poorly suited to the undisturbed conditions of derelict mining areas, and the species is critically dependent on conservation management interventions that re-expose areas of metalliferous substrate. Without such management, the long-term survival of the species is in serious jeopardy.

中文翻译：

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极度濒危的 Ditrichum cornubicum 的生存和对保护管理干预的依赖

摘要

介绍。

Ditrichum cornubicum是世界上最稀有的苔藓植物之一，随着其栖息地逐渐消失在废弃矿区的植被演替中，它正在经历长期的衰退。本研究调查了康沃尔（英国）两个地点的物种丰度的短期变化，包括在 2015 年 9 月发生草坪剥离的试验管理地块内。

方法。

2020 年 1 月对D.cornubicum进行了详细调查，并使用高精度 GPS 记录了位置。

结果。

自 2018 年 1 月以来，该物种在试验管理地块中急剧下降，占用的 0.1 m 网格单元减少了 93%。外审管理地块，同期没有出现这样的下降。

结论。

在试验管理地块中，D.cornubicum在 2015 年 9 月草坪剥离后不久就经历了最初的急剧增长，随后迅速下降。最初的定植可能是由于水铝石滩中的根状芽孢萌发而引起的，通过剥皮而暴露出来。随后的下降至少部分是由于其他殖民者对暴露的矿场弃土的竞争排斥，尤其是红角角齿龙，也许还有弃土表面的化学变化，例如由于浸出。D.cornubicum的生活策略不适合废弃矿区不受干扰的条件，该物种严重依赖保护管理干预措施，重新暴露含金属底物的区域。如果没有这样的管理，该物种的长期生存将处于严重危险之中。