Age and sex differences in numerical responses, dietary shifts, and total responses of a generalist predator to population dynamics of main prey
Age and sex differences in numerical responses, dietary shifts, and total responses of a generalist predator to population dynamics of main prey
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DOI：
10.1007/s00442-020-04607-x
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发表时间：
2020-02-01
期刊：
影响因子：
2.7
通讯作者：
Korpimaki, Erkki
中科院分区：
文献类型：
--
作者：
Masoero, Giulia;Laaksonen, Toni;Korpimaki, Erkki
主要猎物物种丰度的波动可能会通过诱导捕食者的数量反应和饮食变化来塑造动物群落。到目前为止，不同年龄和性别的个体之间的数字反应和饮食变化是否存在差异还没有得到多少关注。这些差异可能会影响多少捕食者消耗的主要和替代猎物，从而导致主要和替代猎物物种的捕食压力的变化。我们研究了秋季波动的主要猎物丰度（田鼠）对欧亚侏儒猫头鹰Glaucidium passerinum（327个个体）食物囤积种群的年龄和性别组成的影响，以及2003-2017年期间芬兰西部食物商店的物种组成（629个食物商店）。随着田鼠数量的增加，一岁以下（< 1岁）的性别和成年（+ 1岁）女性的数量增加。在低田鼠丰度，成年猫头鹰存储更多的小型鸟类和小型哺乳动物比一岁。女性存储更多的小型哺乳动物比男性，并表现出倾向于存储较少的鸟类。消耗的鸟类（最重要的替代猎物），特别是凤头，杨柳，大，蓝山雀的数量，增加与低田鼠密度。我们的研究结果表明，数值，功能，和总的反应侏儒猫头鹰，可能也是其他脊椎动物的捕食者，在冬季的主要猎物的可用性是由年龄和性别组成的捕食者人口，这两个显示大的时空变化在北方森林。
Fluctuations in the abundance of main prey species might shape animal communities, by inducing numerical responses and dietary shifts in predators. Whether numerical responses and dietary shifts differ among individuals of different age and sex has so far gained little attention. These differences could affect how much predators consume main and alternative prey, thus causing variation in predation pressure on main and alternative prey species. We studied the effect of fluctuating main prey abundance (voles) in autumn on the age and sex composition of a food-hoarding population of Eurasian pygmy owls Glaucidium passerinum (327 individuals), and on the species composition of their food stores in western Finland during 2003-2017 (629 food stores). Numbers of yearlings (< 1-year old) of both sexes and adult (+ 1-year old) females increased with increasing vole abundance. During low vole abundance, adult owls stored more small birds and less small mammals than yearlings. Females stored more small mammals than males and showed a tendency to store less birds. The amount of consumed birds (the most important alternative prey), and in particular of crested, willow, great, and blue tits, increased with low vole densities. Our results show that numerical, functional, and total responses of pygmy owls, and probably also other vertebrate predators, to the availability of the main prey in winter are shaped by the age and sex composition of the predator population, which both show large spatio-temporal variation in boreal forests.