Leaf phenology based classification of woody species into discrete evergreen and deciduous categories is widely used in ecology, but these categories hide important variation in leaf phenological behaviour. Few studies have examined the continuous nature of deciduousness and our understanding of variation in quantitative estimates of leaf shedding behaviour and the causes and consequences of this is limited. In this study we monitored leaf phenology in 75 woody species from a seasonally dry tropical forest to quantify three quantitative measures of deciduousness, namely: maximum canopy loss, duration of deciduousness, and average canopy loss. Based on proposed drought tolerance and drought avoidance strategies of evergreen and deciduous species, respectively, we tested whether the quantitative measures of deciduousness were related to leaf functional traits. Additionally, to understand the functional consequences of variation in deciduousness we examined relationships with the timing of leaf flushing and senescing. We found wide and continuous variation in quantitative measures of deciduousness in these coexisting species. Variation in deciduousness was related to leaf function traits, and the timing of leaf flushing. Along a continuous axis ranging from evergreen to deciduous species, increasing deciduousness was associated with more acquisitive leaf functional traits, with lower leaf mass per area and leaf dry matter content, and greater leaf nitrogen content. These results indicate that the continuous nature of deciduousness is an important component of resource acquisition strategies in woody species from seasonally dry forests.

中文翻译：

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季节性干燥热带森林中木本物种落叶性的定量估计与叶片功能性状和叶片潮红的时间有关

在生态学中广泛使用基于叶片物候分类的木本物种分类为离散常绿和落叶类别，但是这些类别掩盖了叶片物候行为的重要变化。很少有研究检查落叶性的连续性，并且我们对叶片脱落行为的定量估计变化的理解以及这种现象的原因和后果是有限的。在这项研究中，我们监测了季节性干燥热带森林中75种木本植物的叶片物候，以定量分析落叶性的三种定量度量，即：最大冠层损失，落叶持续时间和平均冠层损失。根据分别提出的常绿和落叶树种的耐旱性和避免干旱策略，我们测试了落叶性的定量测量是否与叶片功能性状有关。另外，为了了解落叶性变化的功能后果，我们检查了与叶片潮红和衰老的时间之间的关系。在这些共存物种中，我们发现了落叶性定量测量方法的广泛而连续的变化。落叶性的变化与叶片功能性状和潮红的时间有关。沿着从常绿到落叶树种的连续轴，落叶性的增加与更易获取的叶片功能性状有关，单位面积的叶片质量和叶片干物质含量较低，而叶片氮含量较高。