ABSTRACT

The ecological impacts of invasive mammals are widely documented around the world. In New Zealand, fencing designed to exclude non-native mammals is used for conservation and restoration efforts. The Orokonui Ecosanctuary is a 307-hectare coastal Otago reserve (Dunedin, New Zealand) that is surrounded by mammal-exclusion fencing. The goal of the present study was to investigate how excluding mammals and including (native) animals inside the Orokonui Ecosanctuary fence has influenced ground- and litter-dwelling beetle (Coleoptera) abundance, diversity, and community composition. We hypothesised that beetle abundance, diversity, and community composition would be different whether the beetles sampled were from sites inside the fence or outside the fence. Beetles were extracted from the litter and soil of six sites (three inside, three outside) two times (once in winter, once in summer). The abundance, diversity, species composition, size distribution, and trophic guild distribution of beetles inside and outside the fence and between seasons were compared. Our results suggest that sites inside the fence harbour a greater abundance and diversity of beetles. We found a high abundance of native beetles both inside and outside the Orokonui Ecosanctuary’s fence. Further research may find evidence that the fenced sanctuary is providing a ‘halo effect’ whereby native beetles thriving within the Orokonui Ecosanctuary are spreading out into the surrounding landscape and also outcompeting introduced beetles.

摘要

入侵哺乳动物的生态影响在世界各地都有广泛记载。在新西兰，旨在排除非本地哺乳动物的围栏被用于保护和恢复工作。Orokonui 生态保护区是一个占地 307 公顷的奥塔哥沿海保护区（新西兰但尼丁），周围环绕着禁止哺乳动物进入的围栏。本研究的目的是调查在 Orokonui 生态保护区围栏内排除哺乳动物并包括（本地）动物如何影响地栖和凋落物甲虫（鞘翅目）的丰度、多样性和群落组成。我们假设无论采样的甲虫是来自栅栏内还是栅栏外，甲虫的丰度、多样性和群落组成都会不同。从六个地点的垃圾和土壤中提取甲虫（三个在里面，三外）两次（冬季一次，夏季一次）。比较了围栏内外和季节间甲虫的丰度、多样性、物种组成、大小分布和营养群分布。我们的研究结果表明，围栏内的地点藏有更丰富、更多样化的甲虫。我们在 Orokonui 生态保护区的围栏内外发现了大量的本地甲虫。进一步的研究可能会发现有证据表明，围栏保护区正在提供一种“光环效应”，即在 Orokonui 生态保护区内繁衍生息的本地甲虫正在向周围的景观扩散，并在竞争中胜过引进的甲虫。比较了围栏内外和季节间甲虫的营养型分布。我们的研究结果表明，围栏内的地点藏有更丰富、更多样化的甲虫。我们在 Orokonui 生态保护区的围栏内外发现了大量的本地甲虫。进一步的研究可能会发现有证据表明，围栏保护区正在提供一种“光环效应”，即在 Orokonui 生态保护区内繁衍生息的本地甲虫正在向周围的景观扩散，并在竞争中胜过引进的甲虫。比较了围栏内外和季节间甲虫的营养型分布。我们的研究结果表明，围栏内的地点藏有更丰富、更多样化的甲虫。我们在 Orokonui 生态保护区的围栏内外发现了大量的本地甲虫。进一步的研究可能会发现有证据表明，围栏保护区正在提供一种“光环效应”，即在 Orokonui 生态保护区内繁衍生息的本地甲虫正在向周围的景观扩散，并在竞争中胜过引进的甲虫。