Interspecific competition between resident and wintering birds: experimental evidence and consequences of coexistence.
Interspecific competition between resident and wintering birds: experimental evidence and consequences of coexistence.
复制标题
留鸟和越冬鸟之间的种间竞争：实验证据和共存的后果。
作者：
Luke L. Powell;Elizabeth M. Ames;James R. Wright;Jason Matthiopoulos;P. Marra
种间竞争对种群结构和群落动态的贡献仍然存在争议，也没有得到充分的检验。具体来说，种间竞争一直被认为会影响冬季候鸟群落的结构，但实验证据仍然难以捉摸。数十亿鸣禽进入新热带栖息地，在那里他们与居民共存，提供了一个独特的机会来评估种间竞争及其后果。工作在15公顷的牙买加黑红树林，我们使用去除实验，以测试是否占主导地位的居民黄莺竞争种间与下属越冬美国红尾莺，我们还使用了观测证据（种间领土重叠），以了解这种共存是否影响身体状况，春季出发日期或年回报率。与种间竞争一致，实验后删除的居民，一岁的雄性红尾莺（但不是女性或成年男性）立即腾空黄莺领土，增加其重叠的空间由7.3%。一岁的红尾莺似乎也通过积极避免黄莺来调整它们的领土空间使用;例如，红尾莺在一岁时离开越冬地，并在第二个冬天返回，这样它们的领土与黄莺的重叠减少了32%。成年红尾椋鸟则没有这种领土灵活性。成年雄性红尾莺也表现出证据支持共存的后果：领土重叠与黄莺的身体状况和年回报率呈负相关。与黄莺有<25%领土重叠的成年雄性红尾莺在季节之间返回的可能性是100%重叠的三倍多。我们认为，成年雄性红尾椋鸟的领土扩张性产生了这些后果，这可能是由于它们在该特定领土上多年的投资。更一般地说，临时性质的移民居民种间竞争可能是什么让共存在冬季，一年中最资源贫乏的时候。我们的观察表明，种间竞争和共存的后果是特定的年龄和性别的红尾鱼种内优势等级的产品。我们的观察表明，种间共存具有可衡量的后果，我们的实验支持长期以来，但以前未经检验的信念，即居民鸟类竞争种间越冬移民。
The contribution of interspecific competition to structuring population and community dynamics remains controversial and poorly tested. Specifically, interspecific competition has long been thought to influence the structure of migrant-resident bird communities in winter, yet experimental evidence remains elusive. The arrival of billions of songbirds into Neotropical habitats, where they co-exist with residents, provides a unique opportunity to assess interspecific competition and its consequences. Working in 15 ha of Jamaican black mangrove forest, we used removal experiments to test whether dominant resident Yellow Warblers compete interspecifically with subordinate wintering American Redstarts; we also used observational evidence (interspecific territorial overlap) to understand whether this coexistence influences physical condition, spring departure dates or annual return rates. Consistent with interspecific competition, after experimental removal of the resident, yearling male redstarts (but not females or adult males) immediately into vacated Yellow Warbler territories, increasing their overlap with the space by 7.3%. Yearling redstarts also appeared to adjust their territorial space use by actively avoiding Yellow Warblers; for example, redstarts departing the wintering grounds as yearlings and returning the following winter shifted such that their territories overlapped 32% less with those of Yellow Warblers. Adult redstarts showed no such territorial flexibility. Adult male redstarts also showed evidence supporting the consequences of coexistence: territorial overlap with Yellow Warblers was negatively correlated with body condition and annual return rates. Adult male redstarts with <25% territorial overlap with Yellow Warblers were more than three times as likely to return between seasons than those with 100% overlap. We propose that the territorial inflexibility of adult male redstarts produces these consequences, which may be due to their years-long investment in that particular territory. More generally, the temporary nature of migrant-resident interspecific competition is likely what allows coexistence during winter, the most resource poor time of year. Our observations suggest that interspecific competition and the consequences of coexistence are age- and sex-specific and the product of intraspecific dominance hierarchy in redstarts. Our observations suggest that interspecific coexistence has measurable consequences, and our experiments support the long-held, but previously untested belief that resident birds compete interspecifically with wintering migrants.
影响因子：
6.6
作者：
Nakagawa, Shinichi;Schielzeth, Holger
通讯作者：
Schielzeth, Holger