QUESTION: Land‐use change and intensification are currently the most pervasive threats to tropical biodiversity. Yet, their effects on biodiversity change with elevation are unknown. Here, we examine how tree diversity and community composition vary with elevation and how the effects of forest use intensity on tree diversity and community composition change within elevations. LOCATION: Eastern slopes of the Cofre de Perote mountain, state of Veracruz, Mexico. METHODS: We assessed tree diversity and composition using a sampling design in which elevation was crossed with three levels of forest use intensity: old‐growth, degraded, and secondary forests. We established 120 20 m × 20 m forest plots, located at eight sites between 0 m and 3,545 m. At each site, five replicate plots were inventoried for each level of forest use intensity. RESULTS: Our analyses revealed an interactive effect between elevation and forest use intensity affecting tree diversity and community composition along the elevational gradient. Contrasting effects of forest use intensity within elevation resulted in tree diversity following a low‐plateau pattern for old‐growth and a bimodal pattern for degraded and secondary forests. Along the entire elevational gradient, there were 217 tree species distributed within 154 genera and 80 families. Species accumulation curves revealed that forests at 0 m and 1,500 m elevation showed differences in species richness among forest use intensities. In contrast, species richness did not differ between old‐growth forest and the other forest use intensities in five of the eight studied elevations. In terms of community composition, secondary forests differed from old‐growth and degraded forests. CONCLUSION: Our results suggest that the interactive effects of elevation and forest use intensity change tree diversity patterns and community composition along a tropical elevational gradient. Degraded forests were similar to old‐growth forests in terms of species diversity and composition, suggesting that they may act as a safeguard of tree diversity in human‐dominated tropical landscapes.

中文翻译：

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热带海拔梯度上树木多样性和群落组成对森林利用强度的响应

问题：土地利用的变化和集约化是目前热带生物多样性最普遍的威胁。然而，它们对生物多样性随海拔变化的影响尚不清楚。在这里，我们研究了树木多样性和群落组成如何随海拔变化以及森林利用强度对树木多样性和群落组成的影响在海拔高度内如何变化。位置：墨西哥韦拉克鲁斯州 Cofre de Perote 山的东坡。方法：我们使用抽样设计评估树木的多样性和组成，其中海拔与森林利用强度的三个水平交叉：老林、退化林和次生林。我们建立了 120 个 20 m × 20 m 的林地，位于 0 m 和 3,545 m 之间的八个地点。在每个地点，针对每个森林利用强度水平编制了五个重复样地。结果：我们的分析揭示了海拔和森林利用强度之间的相互作用影响沿海拔梯度的树木多样性和群落组成。高程内森林利用强度的对比效应导致树木多样性遵循老林的低高原模式和退化和次生林的双峰模式。沿整个海拔梯度分布有217种树种，分布在154属80科。物种积累曲线显示，0 m和1,500 m海拔的森林在森林利用强度之间表现出物种丰富度的差异。相比之下，在所研究的八个海拔中的五个海拔中，原始森林和其他森林利用强度之间的物种丰富度没有差异。在社区构成方面，次生林不同于原始森林和退化林。结论：我们的研究结果表明，海拔和森林利用强度的相互作用会沿热带海拔梯度改变树木多样性模式和群落组成。退化森林在物种多样性和组成方面与原始森林相似，表明它们可以作为人类主导的热带景观中树木多样性的保护措施。