哀牢山湿性常绿阔叶林木质藤本植物地上部分生物量及其对人为干扰的响应

ABOVEGROUND BIOMASS OF LIANAS AND ITS RESPONSE TO ANTHROPOGENIC DISTURBANCES IN MOIST EVERGREEN BROAD-LEAVED FORESTS IN THE AILAO MOUNTAINS OF SOUTHWESTERN CHINA

木质藤本植物是森林,尤其是热带和亚热带森林中的重要组分。由于野外调查的困难,对其生态学的研究相对较少。对哀牢山原生山地湿性常绿阔叶林和4类次生林中的藤本植物进行了调查,利用48株藤本植物样木实测数据,采用样本回归分析法,选取藤本植物的不同参数作为自变量,分别对冠层和林下两类藤本混合种生物量模型进行了拟合比较,结合样地内长度≥50cm的所有藤本植物的调查资料估算了各森林群落藤本植物地上部分生物量,探讨了原生林中藤本植物地上部分生物量的组成与分布特征,以及人为干扰对藤本植物地上部分生物量的影响。结果表明:1)以藤本基径为自变量建立幂函数回归模型,其相关系数较高,具有较高的实用价值;2)该区山地湿性常绿阔叶林中藤本植物地上部分生物量为9.82×103kg·hm–2,其中冠层藤本(基径≥1.0cm,长度≥5.0m)生物量占藤本植物总生物量的99.70%,林下藤本(基径<1.0cm,长度<5.0m)的地上部分生物量很低;3)人为干扰后林下藤本植物的生物量相对增加,而冠层藤本植物的地上部分生物量显著减少;经过约100年恢复演替的老龄栎类萌生林藤本植物地上部分生物量才达到接近原生林的水平。

Aims Lianas （woody vines） are important floristic and ecological elements in forests throughout the world,especially in tropical and subtropical areas. However,ecological studies on lianas are relatively scarce because field research is difficult. Our objectives were to develop liana biomass regression models,examine liana biomass composition and distribution in a natural moist evergreen broad-leaved forest,and assess the effects of anthropogenic disturbances on the biomass of lianas. Methods We compared power functional models for biomass of canopy lianas （length ≥5.0 m） and understory lianas （length 〈5.0 m） based on 48 samples of lianas, using variables of basal diameter, length, and squared basal diameter × length. In the Ailao Mountains of southwestern China, we established three 20 × 20 m sample plots in each of a natural undisturbed moist evergreen broad-leaved primary forest and four secondary forests： old （100 a） and younger （50 a） secondary Lithocarpus forests, a Populus bonatii secondary forest and an Alnus nepalensis secondary forest. In each plot, we enumerated all liana stems ≥0.5 m in length （from the roots） and measured their basal diameters （30 cm along the stem from roots）. Important findings The regression model developed by liana basal diameters had the highest correlation coefficients and is preferred for practical use because measurement of liana basal diameter is easyand accurate. The total aboveground biomass of lianas in the natural moist evergreen broad-leaved fo est was 9.82×10^3 kg.hm-2, 99.70% of which was canopy lianas. Anthropogenic disturbances result in the decrease of liana biomass. The biomass of understory lianas was relatively greater in younger secondary forests, but the biomass of lianas （especially large canopy lianas） was significantly lower. The aboveground biomass of lianas in the old secondary Lithocarpus forest was 91.03% of that of the natural moist evergreen broad-leaved forest, after about 100 years of restoration succession.