Canopy gaps are widely recognized as being crucial for maintaining the diversity of forest tree communities. But empirical studies have found mixed results because the differences in diversity between individual gaps and non‐gaps are often small and statistically undetectable. One overlooked factor, however, is how small individual gap versus non‐gap differences may accumulate across sites and potentially have a large effect on forest diversity at the plot scale. Our study investigated sapling richness, density, and composition in 124 treefall gaps, and 200 non‐gap sites in the 50‐ha tropical forest plot at Barro Colorado Island (BCI), Panama. Additionally, we analyzed species accumulation curves to understand how species richness increases with increasing stem numbers. We observed that sapling richness and density were only slightly higher in gaps 7 years after formation and statistically indistinguishable from non‐gaps after 12 years. However, species accumulation curves across multiple gaps were substantially higher than those across non‐gaps. Species composition showed small differences between individual gaps and non‐gaps but differed significantly between collections of gaps and non‐gaps. Specifically, 55 species specialized in 7‐year‐old gaps compared with 24 in non‐gaps; of these, 23 gap‐specialized species and zero non‐gap species were pioneers. Our results indicate that tree species richness is higher in gaps because of both higher stem density and the presence of gap‐specialized species. Our study has finally provided compelling evidence to support the idea that gaps enhance the overall diversity of tropical forest tree communities.

中文翻译：

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林隙的高 beta 多样性有助于热带森林中地块级树木的多样性


树冠间隙被广泛认为对于维持森林树木群落的多样性至关重要。但实证研究发现结果喜忧参半，因为个体差距和非差距之间的多样性差异通常很小，并且在统计上无法察觉。然而，一个被忽视的因素是，微小的个体差距与非差距差异如何在地点之间累积，并可能对样地尺度上的森林多样性产生重大影响。我们的研究调查了巴拿马巴罗科罗拉多岛 （BCI） 的 124 个树木落下间隙和 200 个非间隙地点的树苗丰富度、密度和组成。此外，我们分析了物种积累曲线，以了解物种丰富度如何随着茎数量的增加而增加。我们观察到，树苗的丰富度和密度在形成后 7 年在间隙中仅略高，并且在 12 年后与非间隙在统计学上没有区别。然而，跨多个间隙的物种积累曲线远高于跨非间隙的物种积累曲线。物种组成在单个间隙和非间隙之间表现出微小差异，但在间隙和非间隙集合之间差异显著。具体来说，55 个物种专门研究 7 年生的间隙，而 24 个物种专门研究非间隙;其中，23 种间隙特化物种和 0 种非间隙物种是先驱。我们的结果表明，由于较高的茎密度和间隙特化物种的存在，林窗中的树种丰富度更高。我们的研究终于提供了令人信服的证据来支持差距增强了热带森林树木群落整体多样性的观点。