Many island endemics around the world have evolved from populations of colonists. Further colonizations may lead to interactions between older and newer colonists. Little is known, however, regarding the impact of more recent island colonizers on incumbent congeners, partly because of a dearth of examples of natural colonizations in the recent past. Sardinian Warbler (Sylvia melanocephala) recently colonized Cyprus and has rapidly expanded its breeding range. We examined the impact of the Sardinian Warbler colonization on the endemic Cyprus Warbler (S. melanothorax) and on another congener, the Spectacled Warbler (S. conspicillata). We performed 402 population surveys in 32 sample plots across the island, covering five different habitat types and variation across three seasons. Our results show that Cyprus Warbler has undergone a significant decline during the five years of the study, especially in disturbed habitats, while Sardinian and Spectacled Warbler populations have remained stable. Although the longer established Spectacled Warbler clearly segregated habitat with Cyprus Warbler, Sardinian Warbler numbers were negatively associated with Cyprus Warbler abundance, suggesting its presence may contribute to the endemic’s decline. Maquis scrub was favored by both Cyprus Warbler and Sardinian Warbler, but the latter also occurred in high densities in disturbed habitats. The colonizer’s prevalence in disturbed, mixed habitat, suggests it may replace the endemic in parts of its former range following anthropogenic perturbations. Natural colonizations may contribute to rapid population declines in island endemics in a similar way to introduced species, especially when combined with strong effects of habitat disturbance.

中文翻译：

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随着近期殖民者的迅速扩张，塞浦路斯的西尔维亚莺之间的栖息地选择和种间竞争

世界各地的许多岛屿地方病都是从殖民者人口演变而来的。进一步的殖民化可能会导致新老殖民者之间的互动。然而，关于最近的岛屿殖民者对现有同类物的影响知之甚少，部分原因是最近缺乏自然殖民的例子。撒丁岛莺（Sylvia melanocephala）最近在塞浦路斯定居，并迅速扩大了其繁殖范围。我们研究了撒丁岛莺的殖民化对地方性塞浦路斯莺 (S. melanothorax) 和另一种同系物眼镜莺 (S. conspicillata) 的影响。我们在全岛的 32 个样地中进行了 402 次种群调查，涵盖了五个不同的栖息地类型和三个季节的变化。我们的研究结果表明，塞浦路斯莺在研究的五年期间经历了显着下降，尤其是在受干扰的栖息地，而撒丁岛和眼镜莺种群保持稳定。尽管建立时间较长的眼镜莺明确将栖息地与塞浦路斯莺隔离，但撒丁岛莺的数量与塞浦路斯莺的数量呈负相关，表明其存在可能导致地方性鸟类的减少。Maquis 灌木受到塞浦路斯莺和撒丁岛莺的青睐，但后者也在受干扰的栖息地中以高密度出现。殖民者在受干扰的混合栖息地中的流行表明，在人为扰动之后，它可能会取代以前范围内部分地区的地方性。