Data from: Leaf trait variations associated with habitat affinity of tropical karst tree species

1. Karst hills, i.e., jagged topography created by dissolution of limestone and other soluble rocks, are distributed extensively in tropical forest regions, including southern parts of China. They are characterized by a sharp mosaic of water and nutrient availability, from exposed hilltops with poor soil development to valleys with occasional flooding, to which trees show species specific distributions. Here we report the relationship of leaf functional traits to habitat preference of tropical karst trees.
2. We described leaf traits of 19 tropical tree species in a seasonal karst rainforest in Guangxi, China, 12 species in-situ and 13 ex-situ in a non-karst arboretum, which served as a common garden, with six species sampled in both. We examined how the measured leaf traits differed in relation to species’ habitat affinity and evaluated trait consistency between natural habitats vs. the arboretum.
3. Leaf mass per area (LMA) and optical traits (light absorption and reflectance characteristics between 400 and 1050 nm) showed significant associations with each other and habitats, with hilltop species showing high values of LMA and low values of photochemical reflectance index (PRI).
4. For the six species sampled in both the karst forest and the arboretum, LMA, leaf dry matter content, stomatal density and vein length per area showed inconsistent within-species variations, whereas some traits (stomatal pore index and lamina thickness) were similar between the two sites.
5. In conclusion, trees specialized in exposed karst hilltops with little soils are characterized by thick leaves with high tissue density indicative of conservative resources use, and this trait syndrome could potentially be sensed remotely with PRI.

1. 喀斯特丘陵（Karst hills）指由石灰岩及其他可溶性岩石经溶蚀作用形成的崎岖地貌，广泛分布于包括中国南方在内的热带森林区域。该类生境的核心特征为水分与养分有效性的剧烈镶嵌格局：从土壤发育极度匮乏的裸露山顶，到偶发洪涝的河谷地带，生境间差异显著，而林木类群在此类生境中呈现出物种特异性的分布特征。本研究旨在阐明热带喀斯特林木的叶片功能性状与其生境偏好之间的关联。
2. 我们在中国广西一处季节性喀斯特雨林中，针对19种热带林木开展了叶片性状测定：其中12个物种的样本采自原生境，13个物种的样本采自非喀斯特树木园（作为同质园（common garden）），另有6个物种在两类生境中均完成采样。本研究解析了所测定的叶片性状如何随物种生境亲和性发生分化，并评估了自然原生境与树木园之间的性状一致性差异。
3. 叶面积干质量（LMA）与光学性状（400~1050 nm波段的光吸收与反射特性）二者间及与生境均存在显著关联：山顶物种的LMA值较高，而光化学反射指数（PRI）值较低。
4. 对于6种同时在喀斯特森林与树木园采样的物种而言，其LMA、叶片干物质含量、气孔密度及单位面积叶脉长度在种内存在不一致的变异；而部分性状（气孔孔隙指数与叶片厚度）在两个生境间则无显著差异。
5. 综上，特化于土壤极少的裸露喀斯特山顶的林木，其叶片特征表现为叶肉厚实、组织密度较高，这指向保守型资源利用策略；且该性状组合可通过光化学反射指数（PRI）实现遥感监测。