Decades of research suggest that species richness depends on spatial characteristics of habitat patches, especially their size and isolation. In contrast, the habitat amount hypothesis predicts that (1) species richness in plots of fixed size (species density) is more strongly and positively related to the amount of habitat around the plot than to patch size or isolation; (2) habitat amount better predicts species density than patch size and isolation combined, (3) there is no effect of habitat fragmentation per se on species density and (4) patch size and isolation effects do not become stronger with declining habitat amount. Data on eight taxonomic groups from 35 studies around the world support these predictions. Conserving species density requires minimising habitat loss, irrespective of the configuration of the patches in which that habitat is contained.

中文翻译：

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全球物种密度研究综合报告支持栖息地数量假说。

数十年的研究表明，物种丰富度取决于栖息地斑块的空间特征，尤其是其大小和隔离度。相反，栖息地数量假说预测到：（1）固定大小（物种密度）的样地中物种丰富度与样地周围的生境量相比，与斑块大小或隔离度之间有更强的正相关；（2）栖息地数量比斑块大小和隔离的总和能更好地预测物种密度；（3）栖息地破碎本身对物种密度没有影响；（4）斑块大小和隔离的影响不会随着栖息地数量的减少而增强。来自全球35个研究的8个分类学类别的数据支持了这些预测。保护物种密度需要最大程度地减少栖息地损失，