Spatially heterogeneous refugia and predation risk in intertidal salt marshes
Spatially heterogeneous refugia and predation risk in intertidal salt marshes
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潮间带盐沼的空间异质栖息地和捕食风险
DOI：
10.1034/j.1600-0706.2002.960113.x
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发表时间：
2002
期刊：
影响因子：
3.4
通讯作者：
L. Eby
中科院分区：
文献类型：
--
作者：
David B. Lewis;L. Eby
栖息地结构对捕食者和猎物之间相互作用的影响可能在空间上有所不同。在河口盐沼，避难所质量的异质性来自于植被结构和潮汐淹没的空间变化。我们调查了是否捕食的蓝蟹长春花蜗牛的盐沼的向海边缘的距离和主要栖息地结构的特点，光滑的灯心草（互花米草）的影响。大米草可以为蜗牛提供避难所，并干扰螃蟹的觅食。此外，捕食的风险应下降，距离向海边缘，因为向陆地的地区需要更多的旅行时间的螃蟹在潮汐淹没。我们通过对蜗牛和栖息地特征的比较调查、评估螃蟹种群并测量捕食风险的实验以及估计遭遇率的尺寸结构模型来研究这些过程。两者合计，这些方法表明，捕食蜗牛的风险是较低的米草是本和较低的向陆方向。此外，米草的结构和距离向海边缘相互作用。大米草高大或密集的湿地，向海和向陆区域之间的捕食梯度的强度更大。这些捕食梯度的出现，因为植被和距离内陆减少螃蟹和蜗牛之间的相遇率。这项研究表明，栖息地的修改，一个过程并不罕见的盐沼，可能会产生后果的潮间带动物之间的相互作用。
The effect of habitat structure on interactions between predators and prey may vary spatially. In estuarine salt marshes, heterogeneity in refuge quality derives from spatial variation in vegetation structure and in tidal inundation. We investigated whether predation by blue crabs on periwinkle snails was influenced by distance from the seaward edge of the salt marsh and by characteristics of the primary habitat structure, smooth cordgrass (Spartina alterniflora). Spartina may provide refuge for snails and interfere with foraging by crabs. Furthermore, predation risk should decline with distance from the seaward edge because landward regions require more travel time for crabs during tidal inundation. We investigated these processes using a comparative survey of snails and habitat traits, an experiment that assessed the crab population and measured predation risk, and a size-structured model that estimated encounter rates. Taken together, these approaches indicated that predation risk for snails was lower where Spartina was present and was lower in a landward direction. Furthermore, Spartina architecture and distance from the seaward edge interacted. The strength of the predation gradient between seaward and landward regions of the marsh was greater where Spartina was tall or dense. These predation gradients emerge because vegetation and distance inland decrease encounter rates between crabs and snails. This study suggests that habitat modification, a process not uncommon in salt marshes, may have consequences for interactions among intertidal fauna.