New records of Plantago trinitatis: spontaneous regeneration of a species considered extinct or sampling gaps on Trindade Island?

ABSTRACT Trindade Island has lost much of its original vegetation cover as a result of approximately three centuries of human occupation and intense herbivory caused by invasive mammals. Since the eradication of some of these herbivores, the recovery of some plant species has started. Plantago trinitatis is an endemic herb from Trindade Island, which was considered extinct until 1998, when it was rediscovered in the higher areas of the island. The regeneration of the species was attributed to the soil seed bank. This communication reports new records of P. trinitatis close to sea level on Trindade Island, at lower altitude than previously documented. The new records suggest that P. trinitatis is recolonizing the island, but leaves doubts whether sampling gaps in the past have led to the non-detection of the plant in its vegetative form in these locations, emphasizing that other species considered extinct may share this issue. Regardless of recolonization or sampling gaps, the eradication of invasive herbivores is necessary as a strategy to protect local flora and native vegetation. Understanding the population status can help in making decisions about the need of environmental management and species population recovery.

摘要：受约三个世纪的人类定居活动与入侵哺乳动物引发的高强度草食作用影响，特林达迪岛的原生植被覆盖已大幅丧失。自部分此类入侵草食动物被根除以来，部分植物物种已启动恢复进程。Plantago trinitatis是特林达迪岛特有的草本植物（endemic herb），曾被认定为已灭绝物种，直至1998年才在该岛高海拔区域被重新发现。该物种的自然更新被归因于土壤种子库（soil seed bank）。本研究报道了在特林达迪岛近海平面区域发现P. trinitatis的新记录，其分布海拔低于此前已记载的所有点位。这些新记录提示P. trinitatis正重新定植该岛，但同时也引发疑问：过往的采样空白是否导致此前未能在这些区域检测到该植物的营养体？这一发现也凸显出其他被认为已灭绝的物种可能存在类似的未被实际发现的情况。无论是物种主动重新定植，还是过往采样存在疏漏，根除入侵草食动物均是保护当地植物区系与原生植被的必要策略。厘清种群现状可为环境管理决策与物种种群恢复工作提供科学依据。