黔中喀斯特石漠化区不同小生境常见木本植物水分来源特征  

CHARACTERISTICS OF WATER SOURCES OF COMMON PLANT SPECIES IN VARIOUS MICROHABITATS IN KARST ROCKY DESERTIFICATION AREA IN CENTRAL GUIZHOU PROVINCE

作　　者：杜雪莲[1,2] 王世杰[2,3] 罗绪强[2,4] 

机构地区：[1]贵州财经大学资源与环境管理学院,贵州贵阳550025 [2]中国科学院地球化学研究所环境地球化学国家重点实验室,贵州贵阳55002 [3]中国科学院普定喀斯特生态系统观测研究站,贵州普定562100 [4]贵州师范学院地理与旅游学院,贵州贵阳550018

出　　处：《长江流域资源与环境》2015年第7期1168-1176,共9页Resources and Environment in the Yangtze Basin

基　　金：国家自然科学基金项目(41203063;31100187);国家重点基础研究发展规划(973)项目(2013CB956700)

摘　　要：选择黔中清镇市王家寨小流域内不同石漠化植物群落,通过分析测定喀斯特小生境内5种常见木本植物,鼠李、火棘、烟管荚蒾、圆果化香和云贵鹅耳枥与其潜在水源稳定性氢氧同位素组成,研究植物水分来源特征,并通过线性混合模型确定水源贡献比,探讨喀斯特小生境植物水分利用对石漠化过程的适应与响应。结果表明:多数情况下,研究区不同小生境内各植物种在雨季同时利用土壤水和表层岩溶带水,对土壤水的利用比例大于表层岩溶带水。各植物种对表层岩溶带水的利用比例随着石漠化的进行而减小。常绿灌木火棘、鼠李和烟管荚蒾在轻度、无石漠化样地同时利用土壤水和表层岩溶带水,但在中、强度石漠化则多利用土壤水,落叶小乔木圆果化香和云贵鹅耳枥在无石漠化同时利用土壤水和表层岩溶带水,而在轻度石漠化样地仅利用土壤水,这跟不同样地植被类型、干扰方式、土壤情况及裂隙发育等不同有关。Stable isotope analysis can be used to investigate water sources of plants because of no isotopic fractionation during water uptake by terrestrial plants.Ecosystems in the karst region of southwest China are very fragile due to the thin soil layer and intensive infiltration capacity of rock fracture,which result in a very limited amount of water storage for plant uptake.Water retention in the soil zone and shallow fractured rock zone（subcutaneous）is a key factor for plant growth.However,the source of water for plant growth in karst region remains unclear.Distinction of water sources taken by karst plants is a challenging task for botanists and hydrologists, and has important implications for ecosystem management.In this study,we selected 5dominant plant species grown in various micro-habitats in the Wangjiazhai catchment,a typical karst desertification area in Guizhou Province.The spatial heterogeneity of plant water sources at niche scale and the response of the heterogeneity to different karst rocky desertification degree were studied.Proportions of water sources for plant uptake were determined by theδD and δ18 O values of plant stem water,and the water taken from different soil layers and the subcutaneous zone.The following conclusions were drawn from the analysis：（1）TheδD andδ18 O values of soil water were significantly different among various micro-habitats,stony surface had the most positiveδD andδ18 O values,stony crevice had the most negativeδD andδ18 O values,the others had the mediumδD andδ18 O values.TheδD andδ18 O values of soil water were significantly different in soil profile and theδD andδ18 O values of soil water in the 0-10 cm layer were more positive than those in the 10-30 cm layer.（2）The plant species absorbed water from both soil layers and subcutaneous zone and these plant species extracted more water from soil layers than subcutaneous zone in rainy seasons in general.The proportion of plants water use from the subcutaneous zone decreased with increasing degree

关 键 词：喀斯特石漠化 小生境 水分来源 稳定氢氧同位素 

分 类 号：X142[环境科学与工程—环境科学] X171.1