Species distribution patterns are constrained by historical and ecological processes in space and time, but very often the species range sizes are geographical sampling biases resulting from unequal sampling effort. One of the most common definitions of endemism is based on the “congruence of distributional areas” criterion, when two or more species have the same distributional limits. By acknowledging that available data of marine meiobenthic species are prone to geographical sampling bias and that can affect the accuracy of the biogeographical signals, the present study combines analyses of inventory incompleteness and recognition of spatial congruence of Gastrotricha, Kinorhyncha, meiobenthic Annelida and Tardigrada in order to better understand the large-scale distribution of these organisms in coastal and shelf areas of the world. We used the marine bioregionalization framework for geographical operative units to quantify the inventory incompleteness effect (by modelling spatial predictions of species richness) and to recognize areas of endemism. Our models showed that the difference between observed and expected species richness in the Southern Hemisphere is much higher than in the Northern Hemisphere. Parsimony Analysis of Endemicity delimited 20 areas of endemism, most found in the Northern Hemisphere. Distribution patterns of meiobenthic species are shown to respond to events of geographical barriers and abiotic features, and their distribution is far from homogeneous throughout the world. Also, our data show that ecoregions with distinct biotas have at least some cohesion over evolutionary time. However, we found that inventory incompleteness may significantly affect the explanatory power of areas of endemism delimitation in both hemispheres. Yet, whereas future increases in sampling efforts are likely to change the spatial congruence ranges in the Southern Hemisphere, patterns for the Northern Hemisphere may prove to be relatively more resilient.

中文翻译：

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海洋中小型底栖动物特有区域评估的地理抽样偏差

物种分布模式受到空间和时间上的历史和生态过程的限制，但物种范围大小通常是由于采样工作不均而导致的地理采样偏差。特有性最常见的定义之一是基于“分布区域的一致性”标准，当两个或多个物种具有相同的分布限制时。通过承认海洋小型底栖动物物种的可用数据容易出现地理采样偏差并可能影响生物地理信号的准确性，本研究将清单不完整性分析和胃毛、Kinorhyncha、小型底栖动物环节动物和缓步动物的空间一致性识别结合起来，按顺序排列更好地了解这些生物在世界沿海和大陆架地区的大规模分布。我们使用地理操作单元的海洋生物区划框架来量化清单不完整性效应（通过对物种丰富度的空间预测建模）并识别特有区域。我们的模型表明，南半球观察到的和预期的物种丰富度之间的差异远高于北半球。地方病的简约分析划定了 20 个地方病区域，大部分分布在北半球。小型底栖动物的分布模式显示出对地理障碍和非生物特征事件的反应，并且它们的分布在世界范围内远非均质。此外，我们的数据表明，具有不同生物群的生态区在进化过程中至少具有一定的凝聚力。然而，我们发现，清单的不完整性可能会显着影响两个半球特有区域划分的解释力。然而，尽管未来采样工作的增加可能会改变南半球的空间一致性范围，但北半球的模式可能被证明相对更具弹性。