滇南喀斯特地区不同石漠化程度下优势灌木生物量及分配特征

Biomass and distribution characteristics of dominant shrubs under varying degrees of rocky desertification in the karst region of southern Yunnan

灌木在喀斯特石漠化区植被恢复过程中具有重要作用,其生物量大小直接决定了石漠化修复与碳收支情况。为探究喀斯特地区优势灌木树种响应石漠化演替的生物量特征及分配格局,以滇南喀斯特地区不同石漠化程度下3种优势灌木树种华西小石积(Osteomeles schwerinae)、沙针(Osyris lanceolata)和车桑子(Dodonaea viscosa)为研究对象,通过分析其冠幅、树高、基径、各器官(根、茎、叶和花/果)生物量和根冠比等响应特征,并构建各器官、地上和总生物量的异速生长模型。结果表明:(1)不同石漠化梯度下,华西小石积和车桑子的平均生物量呈现“倒V”趋势,而沙针则与前两者不同;(2)不同石漠化梯度下,3种优势灌木各器官生物量的分配大小顺序为茎>根>叶>花/果;(3)3种灌木生物量估测效果较好的是线性函数和幂函数,最佳预测变量以基径(D)、基径平方和树高乘积(D^(2)H)为主。本研究为喀斯特石漠化地区的植被恢复和生态系统碳收支功能的研究提供基础数据。

Shrubs play a crucial role in vegetation restoration in karst rocky desertification areas,with their biomass directly influencing the restoration of rocky desertification and the carbon budget.To explore the biomass characteristics and distribution patterns of dominant shrub species in response to rocky desertification succession,this study focused on three dominant shrub species in the karst areas of southern Yunnan:Osteomeles schwerinae,Osyris lanceolata and Dodonaea viscosa.We analyzed their crown width,tree height,basal diameter,and the biomass of various organs(roots,stems,leaves,and flowers/fruits).The results showed that:(1)Under different rocky desertification gradients,the average biomass of Osteomeles schwerinae and Dodonaea viscosa exhibited an“inverted V”trend,while Osyris lanceolata showed a different pattern.(2)The order of biomass allocation among the organs of the three dominant shrubs under various rocky desertification gradients was:stems>roots>leaves>flowers/fruits.(3)The biomass estimation for the three shrubs was best described by linear and power functions,with the best predictive variables being basal diameter(D)and the product of basal diameter squared and tree height(D^(2)H).This study provides fundamental data for vegetation restoration and ecosystem carbon budget research in karst rocky desertification areas.