Measuring protected-area outcomes with leech iDNA: large-scale quantification of vertebrate biodiversity in Ailaoshan reserve

1 Abstract

Protected areas are central to meeting biodiversity conservation goals, but measuring their effectiveness is challenging. We address this challenge by using DNA from leech-ingested bloodmeals to estimate vertebrate occupancies across the 677 km² Ailaoshan reserve in Yunnan, China. 163 park rangers collected 30,468 leeches from 172 patrol areas. We identified 86 vertebrate species, including amphibians, mammals, birds, and squamates. Multi-species occupancy modelling showed that species richness increased with elevation and distance to reserve edge, including the distributions of most of the large mammals (e.g. sambar, black bear, serow, tufted deer). The exceptions were the three domestic mammal species (cows, sheep, goats) and muntjak deer, which were more common at lower elevations. Vertebrate occupancies are a granular, large-scale conservation-outcome measure that can be used to increase management effectiveness and thus to improve the contributions that protected areas make to achieving global biodiversity goals.

建立自然保护区是实现生物多样性保护的核心措施, 然而如何评估其保护效率仍然是一 个难题。为了解决这一难题, 我们首次利用蚂蝗吸食血液中的DNA(iDNA)进行了一次 大规模的尝试, 对占地677平方公里的位于中国西南部云南省的哀牢山国家自然保护区进 行了一个全局的脊椎动物多样性的评估。在本研究中, 该保护区被划分成172个巡逻区, 由163位护林员在巡视过程中采集了总共30468只蚂蝗, 在这些蚂蝗的测序数据中, 我们鉴 定得到86个脊椎动物物种, 包括两栖类, 鸟类, 哺乳类, 爬行类。我们的多物种占据模型 分析结果显示:在群落水平, 物 丰富度和群落的平均分布随着海拔的升高而增加, 随着 与保护区边缘的距离的缩短而减少;而在物种水平, 三个家养动物物种(牛, 绵羊, 山 羊)和一个野生动物物种(赤麂)在海拔较低的靠近保护区边缘的地区分布更多, 而绝大 多数大型野生哺乳动物(如水鹿, 黑熊, 苏门羚, 黑麂, 野猪)则呈现相反的趋势, 在较 高海拔, 靠近保护区中央的地区分布更多。本研究的结果显示基于蚂蝗的iDNA技术可以为 评估自然保护区对脊椎动物的保护效率创建一个高效的, 可重复的, 易于被大众接受理解 的, 并且可以被审计的结果指标, 该指标可以用于评估保护区对脊椎动物多样性的保护效 率, 从而确保保护区有助于实现全球生物多样性目标。