Trophic roles of black rats and seabird impacts on tropical islands: Mesopredator release or hyperpredation?
Trophic roles of black rats and seabird impacts on tropical islands: Mesopredator release or hyperpredation?
复制标题
黑鼠和海鸟对热带岛屿影响的营养作用：中捕食者的释放还是过度捕食？
DOI：
10.1016/j.biocon.2014.12.014
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发表时间：
2015
影响因子：
5.9
通讯作者：
M. Corre
中科院分区：
文献类型：
--
作者：
D. Ringler;J. Russell;M. Corre
老鼠通过直接捕食蛋和雏鸟影响它们的繁殖成功，从而导致热带海鸟数量的减少。当它们与其他捕食者共存时，入侵大鼠也可能通过它们对群落结构的改变和入侵后的营养相互作用（“过度捕食过程”），或者当顶级捕食者从生态系统中被根除时（“中捕食者释放效应”），产生间接的相互作用。了解这些影响对于实施真正有利于受威胁海鸟种群的恢复行动是必要的。我们在西印度洋的两个法国热带海鸟岛，欧罗巴岛和胡安德诺娃岛研究了这些过程，在那里黑鼠与两种不同的顶级捕食者物种（引进的猫和潜在的本地仓鸮）共存。同时使用几种方法（饮食分析、稳定同位素、海鸟监测）来确定大鼠的营养作用，结果表明，大鼠对海鸟的直接影响在只有大鼠和猫头鹰存在的木卫二上尤为严重，雏鸟的高消耗导致几种海鸟的繁殖成功率低。我们还认为，Juan de Nova岛上正在发生与自上而下的猫的监管相关的过度捕食，尽管猫的领地性可能会缓冲这一过程。相反，我们发现证据表明，无论顶端捕食者的身份如何，中掠食者释放效应都不太可能。考虑到对两个岛屿最可能的影响，我们提出了根除优先事项的建议，以减轻海鸟目前面临的当地灭绝风险。
Rats contribute to the decline of tropical seabird populations by affecting their breeding success through direct predation of eggs and chicks. When they coexist with other predators, invasive rats may also generate indirect interactions via the changes they impose on the structure of communities and trophic interactions following invasion (‘hyperpredation process’), or when apex predators are eradicated from the ecosystem (‘mesopredator release effect’). Understanding these effects is necessary to implement restoration operations that actually benefit threatened seabird populations. We investigated these processes on two French tropical seabird islands of the western Indian Ocean, Europa and Juan de Nova, where black rats coexist with two different apex predator species (introduced cats and potentially native barn owls). The parallel use of several methods (diet analysis, stable isotopes, seabird monitoring) to identify trophic roles of rats revealed that the direct impact of rats on seabirds was particularly high on Europa where only rats and owls occur, with high consumption of chicks resulting in low breeding success for several seabird species. We also suggested that hyperpredation associated with top-down regulation of cats is occurring on Juan de Nova, although territoriality of cats may buffer this process. Conversely we found evidence that mesopredator release effect is unlikely, irrespective of the apex predator identity. Considering the most likely effects on both islands we provided recommendations on eradication priorities to mitigate the risk of local extinction that seabirds are currently facing.