VERTICAL-DISTRIBUTION IN THE SEDIMENT IN THE COOCCURRING BENTHIC AMPHIPODS PONTOPOREIA-AFFINIS AND PONTOPOREIA-FEMORATA
VERTICAL-DISTRIBUTION IN THE SEDIMENT IN THE COOCCURRING BENTHIC AMPHIPODS PONTOPOREIA-AFFINIS AND PONTOPOREIA-FEMORATA
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DOI：
10.2307/3566029
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发表时间：
1987-06-01
期刊：
影响因子：
3.4
通讯作者：
ELMGREN, R
中科院分区：
文献类型：
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作者：
HILL, C;ELMGREN, R
在野外和室内研究了两种食性双足类Pontoporeia affinis和P.femorata在沉积物中的深度分布。在田间夜间，股斑潜蝇发生的深度明显比慈竹大。在沉积物均一的水族箱中，我们发现了与野外相似的深度分布，无论是白天还是夜间，股骨水母都明显比亲缘水母更深，不仅在共生中，在异地也是如此。因此，部分垂直分离可能至少部分是由于这两个物种不同的先天偏好。然而，在共域种群中，深度分布的差异通过交互分离而增强。在共生体中，在夜间发现的亲缘关系比在异地生物中更接近沉积物表面，而在沉积物中(白天和夜间样品汇集时)股骨生物的位置明显更深。我们认为，所展示的互动隔离本身并不意味着发生了种间竞争。还需要其他类型的数据来显示这两个物种之间是否存在真正的竞争。通过在沉积物中挖掘更深的洞穴，股骨松可能会经历更小的捕食压力，从而能够与原本相似、繁殖能力更强的慈竹共存。
The depth distribution in the sediment of the two deposit-feeding amphipods Pontoporeia affinis and P. femorata were investigated in the field and in laboratory experiments. At night in the field, P. femorata occurred significantly deeper than P. affinis. In aquaria with homogenized sediment, we found depth distributions similar to those in the field, with P. femorata occurring significantly deeper than P. affinis, both day and night, not only in sympatry but also in allopatry. The partial vertical separation may thus be at least partly due to different innate preferences of the two species. The difference in depth distribution is, however, enhanced in sympatric populations by interactive segregation. In sympatry, P. affinis was found significantly closer to the sediment surface at night and P. femorata significantly deeper in the sediment (when day and night samples were pooled) than in allopatry. We argue that the interactive segregation demonstrated does not, by itself, imply that interspecific competition occurs. Other types of data are needed to show the presence of real competition between the two species. By burrowing deeper in the sediment, P. femorata may experience reduced predation pressure, and thus be able to coexist with the otherwise similar, and more fecund P. affinis.