Data from: Shifting baselines on a tropical forest frontier: extirpations drive declines in local ecological knowledge

The value of local ecological knowledge (LEK) to conservation is increasingly recognised, but LEK is being rapidly lost as indigenous livelihoods change. Biodiversity loss is also a driver of the loss of LEK, but quantitative study is lacking. In our study landscape in SW China, a large proportion of species have been extirpated. Hence, we were interested to understand whether species extirpation might have led to an erosion of LEK and the implications this might have for conservation. So we investigated peoples' ability to name a selection of birds and mammals in their local language from pictures. Age was correlated to frequency of forest visits as a teenager and is likely to be closely correlated to other known drivers of the loss of LEK, such as declining forest dependence. We found men were better at identifying birds overall and that older people were better able to identify birds to the species as compared to group levels (approximately equivalent to genus). The effect of age was also stronger among women. However, after controlling for these factors, species abundance was by far the most important parameter in determining peoples' ability to name birds. People were unable to name any locally extirpated birds at the species level. However, contrary to expectations, people were better able to identify extirpated mammals at the species level than extant ones. However, extirpated mammals tend to be more charismatic species and several respondents indicated they were only familiar with them through TV documentaries. Younger people today cannot experience the sights and sounds of forest animals that their parents grew up with and, consequently, knowledge of these species is passing from cultural memory. We suggest that engaging older members of the community and linking the preservation of LEK to biodiversity conservation may help generate support for conservation.

本地生态知识（local ecological knowledge，LEK）在生物保护中的价值日益得到认可，但随着原住民生计模式的转变，LEK正快速流失。生物多样性丧失同样会加速LEK的流失，但目前相关定量研究仍较为匮乏。我们在中国西南的研究区域中，已有大量物种发生了局部灭绝。因此，我们希望探究物种局部灭绝是否会导致LEK的流失，以及这一现象对生物保护可能产生的影响。为此，我们通过图片展示的方式，调查了当地人使用当地语言对选定鸟类和哺乳类物种的命名能力。研究发现，青少年时期的森林探访频率与年龄呈显著相关，且该因素大概率与其他已知的LEK流失驱动因子（如森林依赖度降低）紧密相关。我们的结果显示：男性整体上对鸟类的识别能力更强；相较于类群级别（近似对应分类学中的属级），老年人能够更精准地将鸟类识别到物种水平，且这一年龄效应在女性群体中更为显著。然而，在控制上述变量后，物种种群丰度成为决定人们鸟类命名能力的最核心因素。人们无法从物种层面命名任何本地灭绝的鸟类。但与预期相悖的是，人们对本地灭绝哺乳类的物种级识别能力反而强于现存物种。不过，本地灭绝的哺乳类多为极具魅力的物种，多名受访者表示仅通过电视纪录片了解过这些物种。如今的年轻人无法体验到父辈童年时接触的森林动物的视听场景，因此这类物种的相关知识正逐渐从文化记忆中消逝。我们建议，通过吸纳社区中老年成员参与，并将LEK保护与生物多样性保护工作相结合，或可助力凝聚生物保护的社会共识。