Multiple fragmented habitat-patch use in an urban breeding passerine, the Short-toed Treecreeper

Individual responses of wild birds to fragmented habitat have rarely been studied, despite large-scale habitat fragmentation and biodiversity loss resulting from widespread urbanisation. We investigated the spatial ecology of the Short-toed Treecreeper Certhia brachydactyla, a tiny, resident, woodland passerine that has recently colonised city parks at the northern extent of its range. High resolution spatiotemporal movements of this obligate tree-living species were determined using radio telemetry within the urbanized matrix of city parks in Copenhagen, Denmark. We identified regular edge crossing behaviour, novel in woodland birds. While low numbers of individuals precluded a comprehensive characterisation of home range for this population, we were able to describe a consistent behaviour which has consequences for our understanding of animal movement in urban ecosystems. We report that treecreepers move freely, and apparently do so regularly, between isolated habitat patches. This behaviour is a possible driver of the range expansion in this species and may contribute to rapid dispersal capabilities in certain avian species, including Short-toed Treecreepers, into northern Europe. Alternatively, these behaviours might be common and/or provide an adaptive advantage for birds utilising matrix habitats, for example within urban ecosystems.尽管当前全球城市化进程快速蔓延，引发了大规模生境破碎化与生物多样性丧失，但针对野生鸟类对破碎化生境的个体响应的相关研究仍较为稀缺。本研究以短趾旋木雀（Short-toed Treecreeper，*Certhia brachydactyla*）为研究对象，对其空间生态学特征展开调查。该物种体型小巧，为留居性林栖鸣禽，近期在其分布北界的城市公园中成功定居。本研究借助无线电遥测技术，在丹麦哥本哈根的城市公园城市化基质生境中，采集了这一专性树栖物种的高时空分辨率移动数据。研究团队观测到该物种存在规律性的生境边缘穿越行为，这在林栖鸟类中尚属首次报道。尽管本次研究的样本量有限，无法对该种群的家域范围开展全面表征，但我们仍可描述出一种具有一致性的行为模式，这将为深化城市生态系统中动物移动规律的认知提供新的视角。研究结果表明，旋木雀可在隔离的生境斑块间自由移动，且该行为似乎具有规律性。该行为可能是推动该物种分布范围扩张的潜在驱动因素，也可能助力包括短趾旋木雀在内的部分鸟类种群快速扩散至北欧地区。此外，这类行为可能普遍存在于依赖基质生境的鸟类中（如城市生态系统内的鸟类），且能为其带来适应性优势。