Geekiyanage Nalaka, Goodale Uromi Manage, Cao Kunfang, Kitajima Kaoru
Division of Forest and Biomaterial Science Graduate School of Agriculture Kyoto University Kyoto Japan.
Department of Plant Science Faculty of Agriculture Rajarata University Anuradhapura Sri Lanka.
Ecol Evol. 2017 Nov 28;8(1):286-295. doi: 10.1002/ece3.3611. eCollection 2018 Jan.
Karst hills, that is, 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. We described leaf traits of 19 tropical tree species in a seasonal karst rainforest in Guangxi Province, 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 . the arboretum. Leaf mass per area (LMA) and optical traits (light absorption and reflectance characteristics between 400 and 1,050 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). 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. 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.
喀斯特丘陵，即由石灰岩和其他可溶岩溶解形成的锯齿状地形，广泛分布于热带森林地区，包括中国南部。其特点是水分和养分可利用性差异明显，从土壤发育不良的裸露山顶到偶尔发洪水的山谷，树木呈现出特定物种的分布。在此，我们报告热带喀斯特树木叶片功能性状与栖息地偏好的关系。我们描述了中国广西一个季节性喀斯特雨林中19种热带树种的叶片性状，其中12种在原地，13种在非喀斯特树木园异地，该树木园作为一个共同花园，有6种在两地都有采样。我们研究了所测叶片性状在与物种栖息地亲和力方面的差异，并评估了自然栖息地与树木园之间性状的一致性。单位面积叶质量（LMA）和光学性状（400至1050纳米之间的光吸收和反射特性）相互之间以及与栖息地都显示出显著关联，山顶物种的LMA值高，光化学反射指数（PRI）值低。对于在喀斯特森林和树木园都有采样的6个物种，LMA、叶片干物质含量、气孔密度和单位面积叶脉长度在种内表现出不一致的变化，而一些性状（气孔孔隙指数和叶片厚度）在两个地点相似。总之，适应于土壤稀少的裸露喀斯特山顶的树木，其特征是叶片厚且组织密度高，表明资源利用保守，这种性状综合征可能可以通过PRI进行遥感探测。
