神农架国家公园华山松退化群落生态位特征及种间关系

Niche Characteristics and Interspecific Relationships of Degenerated Pinus armandi Community in Shennongjia National Park

为研究神农架国家公园华山松退化群落不同层次的群落结构组成和种间关系,为华山松群落的植被恢复提供科学依据,以华山松大小蠹虫害2年的华山松群落为研究对象,采用重要值、生态位宽度、生态位重叠度等指标分析群落乔木层和灌木层物种组成特征,应用方差比率法、Pearson相关检验和Spearman秩相关检验研究群落总体联结性及种间关系。结果表明:华山松群落乔木层共有10科14属16种植物,灌木层共有23科30属35种植物;华山松、蓬藟分别是乔木层和灌木层的第1优势种。华山松和漆在乔木层中的生态位宽度较大,灌木层中蓬藟、南蛇藤和木姜子的生态位宽度较大,表明这些物种具有较强的生境适应性。乔木层和灌木层的生态位重叠指数分别为0~0.96和0~0.85,其中生态位重叠指数为0的种对数占总种对数的比例分别为32.50%和67.90%,说明各层次存在生态资源利用不充分的现象,在灌木层更为明显。乔木层和灌木层的总体联结性均表现为不显著正联结;群落中呈负联结的种对数多于正联结的种对数,显著或极显著负联结的种对数也高于显著或极显著正联结的种对数,说明群落种间竞争较为激烈;在乔木层,华山松与锐齿槲栎均呈显著正联结关系,与其他物种间多呈负联结关系。可见,华山松群落总体处于不稳定状态,种间关系多为负联结状态,在后期植被恢复过程中,可以自然恢复为主,适当选择生态位较宽、与优势树种呈正联结状态的树种进行人工补植以促进植被恢复;同时注重对可能成为特有种的物种生境进行保护,维持生物多样性。

Studying the community structure and interspecific relationship at different levels of degenerated Pinus armandii community in Shennongjia National Park ecosystem can provide theoretical basis for vegetation restoration.The P.armandi community was taken as the research subject in this study,which has experienced the pest infestation of Dendroctonus armandi for 2 years.The species composition characteristics of tree layer and shrub layer were analyzed by using the indexes such as importance value,niche width and niche overlapping.The variance ratio method,Pearson correlation test and Spearman rank correlation test were used to study the overall interspecific association and relationship of the community.The findings revealed that there were 16 species of plants belonging to 14 genera and 10 families in the arbor layer and 35 species belonging to 30 genera and 23 families in the shrub layer.P.armandi and Rubus hirsutus were the first dominant species in the arbor layer and shrub layer.P.armandi and Toxicodendron vernicifluum had wider niche width in the arbor layer.Rubus hirsutus had the widest niche width in the shrub layer,and followed by Celastrus orbiculatus and Litsea pungens,which indicated that these species have strong habitat adaptability.The niche overlap indices of arbor layer and shrub layer were 0-0.96 and 0-0.85,respectively,in which the proportion of species pairs without niche overlap in arbor layer and shrub layer accounted for 32.50%and 67.90%of the total species pairs.These results showed that ecological resources had not been insufficient utilized in each layers,and this condition was more obvious in the shrub layer.The overall associations of tree layer and shrub layer were not significant positive.The results of correlation test showed that the number of species pairs with negative association was more than that with positive association,and the number of species pairs with significant or extremely significant negative association was also higher than that with significant or extremely significant positive association,indicated that the competition of the relationship among species was fierce.In arbor layer,P.armandi was significant positive connected wtih Quercus aliena var.acutiserrat,while was negative connected wtih most other species.To conclude,the P.armandi community was generally in an unstable state,and the interspecific relationship was mostly in a negative connection state.In the later process of vegetation restoration,natural restoration can be the main method.Appropriate tree species with wide niche and positive association with dominant tree species shall be selected for artificial replantation to promote vegetation restoration.At the same time,attention shall be paid to the protection of species habitats that may become endemic species to maintain biodiversity.