Data from: Movements of four native Hawaiian birds across a naturally fragmented landscape

Animals often increase their fitness by moving across space in response to temporal variation in habitat quality and resource availability, and as a result of intra and inter-specific interactions. The long-term persistence of populations and even whole species depends on the collective patterns of individual movements, yet animal movements have been poorly studied at the landscape level. We quantified movement behavior within four native species of Hawaiian forest birds in a complex lava-fragmented landscape: Hawai‛i ‘Amakihi (Chlorodrepanis virens), ‘Oma‘o (Myadestes obscurus), ‘Apapane (Himatione sanguinea), and ‘I‘iwi (Drepanis coccinea). We evaluated the relative importance of six potential intrinsic and extrinsic drivers of movement behavior and patch fidelity: 1) forest fragment size, 2) the presence or absence of invasive rats (Rattus sp.), 3) season, 4) species, 5) age, and 6) sex. The study was conducted across a landscape of 34 forest fragments varying in size from 0.07 to 12.37 ha, of which 16 had rats removed using a treatment-control design. We found the largest movements in the nectivorous ‘Apapane and ‘I‘iwi, intermediate levels in the generalist Hawai‛i ‘Amakihi, and shortest average movement for the ‘Oma‘o, a frugivore. We found evidence for larger patch sizes increasing patch fidelity only in the ‘Oma‘o, and an effect of rat-removal increasing patch fidelity of Hawai‛i ‘Amakihi only after two years of rat-removal. Greater movement during the non-breeding season was observed in all species, and season was an important factor in explaining higher patch fidelity in the breeding season for ‘Apapane and ‘I‘iwi. Sex was important in explaining patch fidelity in ‘Oma‘o only, with males showing higher patch fidelity. Our results provide new insights into how these native Hawaiian species will respond to a changing environment, including habitat fragmentation and changing distribution of threats from climate change.

动物通常会通过在空间中移动，响应生境质量与资源可获得性的时间变化，同时也会因种内与种间的相互作用提升自身适合度。种群乃至整个物种的长期存续，依赖于个体移动的集体模式，但目前学界在景观尺度上对动物移动的研究仍较为匮乏。本研究针对复杂熔岩破碎化景观中的4种夏威夷原生林鸟的移动行为展开量化分析，涉及物种包括：夏威夷‘Amakihi（Chlorodrepanis virens）、‘Oma‘o（Myadestes obscurus）、‘Apapane（Himatione sanguinea）以及‘I‘iwi（Drepanis coccinea）。我们评估了影响移动行为与斑块保真度（patch fidelity）的6种潜在内在与外在驱动因子的相对重要性：1）森林片段面积；2）入侵鼠类（Rattus sp.）的存在与否；3）季节；4）物种；5）年龄；6）性别。本研究覆盖了34处面积介于0.07至12.37公顷的森林片段组成的景观，其中16处通过对照实验设计移除了入侵鼠类。研究结果显示，食蜜性的‘Apapane与‘I‘iwi的移动距离最长，广食性的夏威夷‘Amakihi移动距离处于中等水平，而食果性的‘Oma‘o平均移动距离最短。仅在‘Oma‘o群体中观测到更大的斑块面积会提升其斑块保真度；鼠类移除仅在实施两年后，对夏威夷‘Amakihi的斑块保真度产生提升作用。所有物种均表现出非繁殖季移动性更强的特征；季节是解释‘Apapane与‘I‘iwi在繁殖季斑块保真度更高的重要因子。仅在‘Oma‘o群体中，性别对斑块保真度的影响具有统计学意义，雄性个体的斑块保真度更高。本研究结果为理解这些夏威夷原生鸟类如何响应包括生境破碎化以及气候变化引发的威胁分布变化在内的环境变化提供了全新的学术视角。