Contributions of detrital subsidies to aboveground spiders during secondary succession, revealed by radiocarbon and stable isotope signatures
Contributions of detrital subsidies to aboveground spiders during secondary succession, revealed by radiocarbon and stable isotope signatures
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DOI：
10.1007/s00442-012-2446-1
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发表时间：
2013-04-01
期刊：
影响因子：
2.7
通讯作者：
Tayasu, Ichiro
中科院分区：
文献类型：
--
作者：
Haraguchi, Takashi F.;Uchida, Masao;Tayasu, Ichiro
来自碎屑的猎物补贴为树栖群落增加了营养和能量。为了了解食物网动态如何响应周围环境的变化，需要测量这种补贴。灌木蜘蛛是参与食物网耦合的主要捕食者之一。我们评估了二次演替过程中猎物可用性的潜在变化对碎屑食物网补贴对灌木蜘蛛的贡献的影响，以及不同蜘蛛摄食行会如何利用碎屑食物网猎物的补贴。我们使用 C (delta C-13)、N (delta N-15) 和 C 同位素歧视 (Delta C-14) 稳定同位素的比率来衡量补贴对蜘蛛饲养协会的相对重要性。饮食年龄是根据 Delta C-14 值计算的，因为蜘蛛的旧饮食年龄表明蜘蛛从碎屑食物来源中捕食猎物。与树栖猎物相比，优势空中猎物（双翅目）的饮食年龄明显较老，这表明空中猎物受到碎屑食物网的补贴。坐等蜘蛛的饮食年龄往往比活跃的狩猎蜘蛛大，这表明坐等蜘蛛更多地依赖补贴。不同年龄的蜘蛛的饮食年龄变化不大，这表明蜘蛛使用放牧和碎屑猎物的比率可能更多地取决于觅食策略，而不是由林龄决定。坐等捕食者的主导地位将导致灌木栖息地的碎屑补贴投入更高。这项研究强调了灌木蜘蛛群落结构（摄食行会组成）对从碎屑食物网获得的补贴量的影响。
Prey subsidies originating from detritus add nutrients and energy to arboreal communities. Measurement of this subsidy is required in the understanding of how food web dynamics respond to changes in surrounding environments. Shrub spiders are one of the key predators involved in food web coupling. We evaluate the effects of potential changes in prey availabilities during secondary succession on the contribution of subsidy from detrital food webs to shrub spiders and how different spider feeding guilds used the subsidy of prey from detrital food webs. We measured the relative importance of the subsidy for the spider feeding guilds, using the ratios of stable isotopes of C (delta C-13), and N (delta N-15) and C isotope discrimination (Delta C-14). Diet age was calculated from Delta C-14 values, because old diet ages of spiders indicate that the spiders consume prey from detrital food sources. Dominant aerial prey (Diptera) had a distinctively old diet age compared with arboreal prey, which indicates that aerial prey were subsidized from detrital food webs. Sit-and-wait spiders tended to have an older diet age than active hunting spiders, which indicates that sit-and-wait spiders depended more on subsidies. Diet age varied only slightly for spiders in stands of different ages, indicating that rates at which spiders use grazing and detrital prey are probably determined more by foraging strategies and not by stand age. A dominance of sit-and-wait predators will lead to higher detrital subsidy inputs in shrub habitats. This study highlights the effect of shrub spider community structure (feeding guild composition) on the volume of the subsidy received from the detrital food web.