Here, we examine the influence of the spatial distribution of open white‐sand campina (WSC) in the Amazon on the species richness and beta diversity of their vascular plants. It is well known that beta diversity tends to increase with geographical distance, but the influence of habitat insularity on floristic composition and endemism is still unclear. We surveyed WSC in central and southwestern Amazon, generating lists of species occurrences by rapid‐inventory techniques to evaluate the influence of island area and connectivity on alpha and beta diversity among five landscapes in the Amazon Basin. Effects of insularity were assessed by comparing alpha and beta diversity within and among landscapes. A high proportion of species (~74%) and genera (~50%) were restricted to only one of the five landscapes and only three species and 28 genera were shared among all landscapes. At the regional scale, beta diversity increased significantly with distance. Partitioning of beta diversity showed that landscapes of higher connectivity have greater turnover and lower nestedness. We conclude that the flora of WSC is highly structured at regional scales, while at the local scale structure is evident only in low connectivity landscapes. Landscape metrics apparently play an important role in shaping patterns of diversity regionally as a result of processes operating at larger geographical scales. This emphasizes that conservation policy should not be local in its geographical focus and should account for connectivity at larger scales. This study is the first to empirically and explicitly evaluate the pattern of endemism in lowland WSC in the Amazon.

中文翻译：

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绿色海洋中的岛屿：亚马逊白沙植被的空间结构性特有性

在这里，我们研究了亚马逊开放式白沙坎皮纳（WSC）的空间分布对其维管植物物种丰富度和β多样性的影响。众所周知，β多样性会随着地理距离的增加而增加，但是生境孤立对植物组成和特有性的影响仍然不清楚。我们对亚马逊中部和西南部的WSC进行了调查，通过快速清点技术生成了物种发生清单，以评估岛屿面积和连通性对亚马逊盆地五种景观中α和β多样性的影响。通过比较景观内部和景观之间的alpha和beta多样性，评估了岛屿的影响。很大比例的物种（〜74％）和属（〜50％）仅限于五个景观之一，并且所有景观中只有三个物种和28个属共享。在区域范围内，β多样性随着距离的增加而显着增加。对β多样性的分区显示，具有较高连通性的景观具有较高的营业额和较低的嵌套度。我们得出的结论是，WSC的植物区系在区域尺度上是高度结构化的，而在局部尺度上，结构仅在低连通性景观中才明显。由于在较大的地理尺度上进行的过程，景观指标显然在塑造区域多样性格局中起着重要作用。这强调了保护政策在其地理重点上不应局限于本地，而应在更大范围内说明连通性。