We introduce and test the subhabitat dependence hypothesis (SDH) in biogeography. This hypothesis posits that biogeographic pattern within a region differs when determined with species abundance data from different subhabitat types. It stems from the notion that the main abiotic factors that drive species distribution in different subhabitat types across a biogeographic region often vary differently across space. To test the SDH, we measured the abundance of algae and sessile invertebrates in two different subhabitats (high intertidal zone and mid-intertidal zone) at eight locations along the Atlantic Canadian coast. We conducted multivariate analyses of the species abundance data to compare alongshore biogeographic pattern between both zones. For both subhabitat types, location groupings based on community similarity not always responded to geographic proximity, leading to biogeographic patchiness to some extent. Nonetheless, both biogeographic patterns were statistically unrelated, thus supporting the SDH. This lack of concordance was most evident for southern locations, which clustered together based on high-intertidal data but showed considerable alongshore patchiness based on mid-intertidal data. We also found that the ordination pattern of these eight locations based on sea surface temperature data was significantly related to biogeographic pattern for the mid-intertidal zone but not for the high intertidal zone. This finding supports the rationale behind the SDH due to the longer periods of submergence experienced by the mid-intertidal zone. Overall, we conclude that biogeographic pattern within a region can depend on the surveyed subhabitat type. Thus, biological surveys restricted to specific subhabitats may not properly reveal biogeographic pattern for a biota as a whole or even just for other subhabitats. As many studies generate biogeographic information with data only for specific subhabitats, we recommend testing the SDH in other systems to determine its domain of application.

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生物地理格局的亚生境依赖性

我们介绍并检验了生物地理学中的亚生境依赖假设 (SDH)。该假设假定，当使用来自不同亚生境类型的物种丰度数据确定时，一个区域内的生物地理模式会有所不同。它源于这样一种观念，即推动物种分布在不同亚生境类型的生物地理区域的主要非生物因素通常在空间上不同。为了测试 SDH，我们测量了加拿大大西洋沿岸八个地点的两个不同亚生境（高潮间带和中潮间带）中藻类和无柄无脊椎动物的丰度。我们对物种丰度数据进行了多变量分析，以比较两个区域之间的沿岸生物地理模式。对于两种亚生境类型，基于社区相似性的位置分组并不总是对地理邻近性做出反应，从而在一定程度上导致生物地理斑块状。尽管如此，两种生物地理模式在统计上都不相关，因此支持 SDH。这种缺乏一致性在南部地区最为明显，这些地区基于高潮间带数据聚集在一起，但基于潮间带数据显示出相当大的沿岸斑块。我们还发现，基于海面温度数据的这八个位置的排序模式与中潮间带的生物地理模式显着相关，但与高潮间带的生物地理模式无关。这一发现支持了 SDH 背后的基本原理，因为中潮间带经历了更长的淹没时间。全面的，我们得出结论，一个区域内的生物地理格局可能取决于所调查的亚生境类型。因此，仅限于特定亚生境的生物调查可能无法正确揭示整个生物群甚至其他亚生境的生物地理模式。由于许多研究仅使用特定亚生境的数据生成生物地理信息，我们建议在其他系统中测试 SDH 以确定其应用领域。