Predator/Prey-Interactions Promote Decomposition of Low-Quality Detritus
Predator/Prey-Interactions Promote Decomposition of Low-Quality Detritus
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DOI：
10.1007/s13157-012-0326-4
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发表时间：
2012-10-01
期刊：
影响因子：
2
通讯作者：
Zimmer, Martin
中科院分区：
文献类型：
--
作者：
Ewers, Christine;Beiersdorf, Anika;Zimmer, Martin
对腐食动物的捕食预计会减缓腐食动物介导的分解过程。在野外环境中，我们分别研究了活栎树（Quercus virginiana）和火龙松（Pinus taeda）凋落叶和针叶的分解是否受到盐沼营养动物（Gastropoda: Littoraria irorata和Melampus bidentatus）和食性杂食动物（Decapoda: Armases cinereum）的影响及其相互作用。单独使用螃蟹和蜗牛都增加了橡树凋落物的分解（质量损失）率，而两者加在一起导致的质量损失与无动物对照相同，可能是由于螃蟹以蜗牛为食而不是凋落物。单独的螃蟹和蜗牛都不影响松凋落物的质量损失，但两者的结合显著增加了分解率。无论哪种凋落物类型，螃蟹都显著增加了蜗牛的死亡率，但只有在松木凋落物上，只有在有食腐蜗牛存在的情况下，螃蟹才能获得生物量。我们的研究结果表明，杂食性半陆生蟹的食性猎物（盐沼蜗牛）单向促进了低质量（松）凋落物的分解。相比之下，在高质量（橡树）凋落物上，捕食者的负面影响普遍存在，导致螃蟹存在时分解率下降，这可能是由于捕食食腐蜗牛。因此，捕食者/猎物相互作用对分解过程的影响依赖于环境，并受资源质量控制。
Predation on detritivores is expected to decelerate detritivore-mediated decomposition processes. In field mesocosms, we studied whether the decomposition of leaf and needle litter of live oak (Quercus virginiana) and loblolly pine (Pinus taeda), respectively, was affected by saltmarsh detritivores (Gastropoda: Littoraria irrorata and Melampus bidentatus) and predacious omnivores (Decapoda: Armases cinereum) and their interactions. Both crabs and snails alone increased decomposition (mass loss) rates of oak litter, while a combination of both resulted in the same mass loss as in animal-free controls, probably due to crabs feeding on snails rather than litter. Neither crabs nor snails alone affected mass loss of pine litter, but a combination of both significantly increased decomposition rates. Irrespective of the litter type, crabs significantly increased mortality of the snails but gained biomass only on pine litter and only when detritivorous snails were present. Our findings suggest that unidirectional facilitation of omnivorous semi-terrestrial crabs by their detritivorous prey (saltmarsh snails) promotes the decomposition of low-quality (pine) litter. On high-quality (oak) litter, by contrast, negative effects of the predator prevail, resulting in a drop of decomposition rates when crabs were present, probably owing to predation on detritivorous snails. Thus, the effects of predator/prey-interactions on decomposition processes are context-dependent and are controlled by resource quality.