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），即由石灰岩及其他可溶性岩石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。其核心特征为水、养分可利用性的高度异质镶嵌格局：从土壤发育极差的裸露山顶，到间歇性洪涝频发的河谷，不同生境间差异显著，树木类群亦呈现出物种特异性的生境分布偏好。本研究聚焦热带喀斯特树木的叶片功能性状与生境偏好之间的关联。
2. 本研究以中国广西一处季节性喀斯特热带雨林为研究对象，共测定了19种热带树木的叶片性状：其中12个物种在原生境（in-situ）取样，13个物种在非喀斯特树木园（作为同质种植园）进行迁地（ex-situ）取样，另有6个物种在两类生境中均完成采样。本研究旨在探究测定的叶片性状如何随物种生境偏好发生差异，并评估自然生境与树木园之间的叶片性状一致性。
3. 比叶重（Leaf mass per area, LMA）与光学性状（400~1050 nm波段的光吸收与反射特征）彼此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（photochemical reflectance index, PRI）值较低。
4. 对于在喀斯特森林与树木园均完成采样的6个物种而言，其比叶重、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显著的生境差异，而气孔孔隙指数与叶片厚度两类性状在两个采样点间无显著差异。
5. 综上，特化于低土壤覆盖裸露喀斯特山顶的树木，通常具有叶片厚实、组织密度较高的特征，这反映了其保守型的资源利用策略；而此类性状组合可通过光化学反射指数（PRI）实现遥感监测。