Purpose of Review

Tropical Montane Cloud Forest (TMCF) is a highly vulnerable ecosystem, which occurs at higher elevations in tropical mountains. Many aspects of TMCF vegetation functioning are poorly understood, making it difficult to quantify and project TMCF vulnerability to global change. We compile functional traits data to provide an overview of TMCF functional ecology. We use numerical models to understand the consequences of TMCF functional composition with respect to its responses to climate and link the traits of TMCF to its environmental conditions.

Recent Findings

TMCF leaves are small and have low SLA but high Rubisco content per leaf area. This implies that TMCF maximum net leaf carbon assimilation (A_n) is high but often limited by low temperature and leaf wetting. Cloud immersion provides important water and potentially nutrient inputs to TMCF plants. TMCF species possess low sapwood specific conductivity, which is compensated with a lower tree height and higher sapwood to leaf area ratio. These traits associated with a more conservative stomatal regulation results in a higher hydraulic safety margin than nearby forests not affected by clouds. The architecture of TMCF trees including its proportionally thicker trunks and large root systems increases tree mechanical stability.

Summary

The TMCF functional traits can be conceptually linked to its colder and cloudy environment limiting A_n, growth, water transport and nutrient availability. A hotter climate would drastically affect the abiotic filters shaping TMCF communities and potentially facilitate the invasion of TMCF by more productive lowland species.

中文翻译：

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气候如何影响热带山地云雾森林的功能

审查目的

热带山地云雾森林（TMCF）是一个高度脆弱的生态系统，发生在热带山区的较高海拔。对TMCF植被功能的许多方面了解甚少，因此难以量化和预测TMCF对全球变化的脆弱性。我们收集功能性状数据以提供TMCF功能生态学概述。我们使用数值模型来了解TMCF功能组成对气候响应的后果，并将TMCF的特性与其环境条件联系起来。

最近的发现

TMCF叶片小，SLA低，但每叶面积的Rubisco含量高。这意味着TMCF的最大净叶片碳同化度（A _n）高，但通常受低温和叶片润湿的限制。浸云为TMCF植物提供了重要的水和潜在的养分输入。TMCF物种的边材比电导率较低，这可以通过较低的树高和较高的边材与叶面积比得到补偿。这些特性与更保守的气孔调节相关，从而导致水力安全裕度高于不受云层影响的附近森林。TMCF树木的体系结构（包括成比例的较粗的树干和较大的根系）提高了树木的机械稳定性。

概要

TMCF的功能性状可以在概念上与其较冷和多云的环境联系起来，从而限制A _n，生长，水的运输和养分的利用率。较热的气候将严重影响塑造TMCF群落的非生物滤池，并可能促进生产力更高的低地物种对TMCF的入侵。