SummaryInvasive predators have decimated island biodiversity worldwide. Rats (Rattus spp.) are perhaps the greatest conservation threat to island fauna. The ground nesting Palau Micronesian Scrubfowl Megapodius laperouse senex (Megapodiidae) inhabits many of the islands of Palau’s Rock Island Southern Lagoon Conservation Area (RISL) in the western Pacific. These islands are also heavily visited by tourists and support populations of introduced rats, both of which may act as added stressors for the scrubfowl. Using passive chew-tag and call playback surveys on five tourist-visited and five tourist-free islands, we investigated if rats and tourists negatively affect scrubfowl, and if higher rat activity is associated with tourist presence. Rat detection probability and site occupancy were significantly higher on tourist visited (89% and 99%, respectively) compared to tourist-free islands (52% and 73%). Scrubfowl were detected at significantly more stations on tourist-free (93%) than tourist visited (47%) islands and their relative abundance was higher (2.66 and 1.58 birds per station, respectively), although not statistically significantly. While rat occupancy probability likewise had a non-significant negative effect on scrubfowl numbers across islands, our results show a negative relationship between tourist presence and scrubfowl in the RISL. Our findings also suggest that rat populations may be augmented by tourist visitation in the RISL. Although this situation may not seriously affect the scrubfowl, it may be highly detrimental to populations of other threatened island landbirds.

中文翻译：

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入侵性老鼠和旅游业对受威胁岛屿鸟类的影响：帕劳密克罗尼西亚灌木鸟

摘要入侵性捕食者已经在全球范围内摧毁了岛屿的生物多样性。大鼠 (家鼠spp.) 可能是对岛屿动物群的最大保护威胁。帕劳密克罗尼西亚灌木鸟的地面筑巢大脚鲀(Megapodiidae) 栖息在西太平洋帕劳岩岛南部泻湖保护区 (RISL) 的许多岛屿上。这些岛屿也有大量游客参观，并支持引进老鼠的数量，这两者都可能成为灌木丛鸟类的额外压力源。使用被动咀嚼标签和呼叫回放调查对五个游客参观和五个游客免费岛屿进行调查，我们调查了老鼠和游客是否会对灌木丛产生负面影响，以及较高的老鼠活动是否与游客的存在有关。与无游客岛屿（52% 和 73%）相比，游客访问的老鼠检测概率和场地占用率（分别为 89% 和 99%）显着更高。在没有游客的岛屿 (93%) 上检测到 Scrubfowl 的站点明显多于游客访问 (47%) 的岛屿，并且它们的相对丰度更高（2.66 和 1。每个站分别有 58 只鸟），尽管没有统计学意义。虽然老鼠入住概率同样对岛屿上的灌木丛数量有不显着的负面影响，但我们的结果显示游客人数与 RISL 中的灌木丛之间存在负相关关系。我们的研究结果还表明，RISL 的游客访问可能会增加老鼠的数量。尽管这种情况可能不会严重影响灌木丛，但它可能对其他受威胁的岛屿陆鸟种群极为不利。我们的研究结果还表明，RISL 的游客访问可能会增加老鼠的数量。虽然这种情况可能不会严重影响灌木丛，但它可能对其他受威胁的岛屿陆鸟种群极为不利。我们的研究结果还表明，RISL 的游客访问可能会增加老鼠的数量。虽然这种情况可能不会严重影响灌木丛，但它可能对其他受威胁的岛屿陆鸟种群极为不利。