Dark extinction: The problem of unknown historical extinctions

<b>Abstract</b><br/><p>The extinction of species before they are discovered and named (dark extinction, DE) is widely inferred as a significant part of species loss in the ‘pre-taxonomic’ period (approx. 1500–1800 CE) and, to some extent, in the ‘taxonomic period’ (approx. 1800–present) as well. The discovery of oceanic islands and other pristine habitats by European navigators and the consequent introduction of destructive mammals, such as rats and goats, started a process of anthropogenic extinction. Much ecosystem change happened before systematic scientific recording, so has led to DE. Statistical methods are available to robustly estimate DE in the ‘taxonomic period’. For the ‘pre-taxonomic period’, simple extrapolation can be used. The application of these techniques to world birds, for example, suggests that approximately 56 DEs occurred in the ‘taxonomic period’ (1800–present) and approximately 180 in the ‘pre-taxonomic period’ (1500–1800). Targeting collection activities in extinction hotspots, to make sure organisms are represented in collections before their extinction, is one way of reducing the number of extinct species without a physical record (providing that collection efforts do not themselves contribute to species extinction).</p>

<b>摘要</b><br/><p>物种在被发现和命名之前即走向灭绝（暗灭绝（dark extinction, DE）），被广泛认定为“前分类学时期”（约公元1500–1800年）物种丧失的重要组成部分，且在一定程度上也存在于“分类学时期”（约公元1800年至今）。欧洲航海家发现海洋岛屿及其他原生栖息地后，随之引入鼠类、山羊等具有破坏性的哺乳动物，由此开启了人为灭绝进程。诸多生态系统变化发生在系统性科学记录之前，进而引发了暗灭绝现象。现有统计方法可对“分类学时期”的暗灭绝开展稳健估算；针对“前分类学时期”，则可采用简单外推法进行估算。以全球鸟类为例应用此类技术的研究结果显示，“分类学时期”（1800年至今）约发生56起暗灭绝事件，“前分类学时期”（1500–1800年）约发生180起。针对灭绝热点区域开展标本采集工作，确保物种在灭绝前能留有实物馆藏记录（前提是采集活动本身不会加剧物种灭绝），是减少无实物记录灭绝物种数量的可行途径之一。</p>