长白山次生杨桦林树种多样性格局多尺度分析

Multi-scale analysis on tree diversity pattern in a secondary Populus davidiana-Betula platyhylla forest in Changbai Mountains,northeastern China

从植物种群角度出发研究物种对局域群落多样性格局的影响,有助于更好地揭示群落水平研究中易于被掩盖的种间互作等作用机制对群落组建过程的影响。研究了不同空间尺度上树种对局域多样性格局的影响,检验了促进种、中性种和抑制种在群落多样性格局组建中所起的作用。以长白山5.2 hm2次生杨桦林监测样地数据为基础,采用单物种-面积关系模型计算29个树种的ISAR和m ISAR曲线,并用完全空间随机化方法检验了单物种-面积关系偏离中性的显著性。研究结果表明,不同树种在不同空间尺度上对局域多样性格局影响不同;样地中臭松、簇毛槭、色木槭、山杨、水榆和紫椴为多样性促进种,白桦和春榆为多样性抑制种;水曲柳、蒙古栎、山丁子和暴马丁香在小尺度上为中性种,其他树种在小尺度上均表现为促进种。多样性促进种、中性种和抑制种对群落多样性格局组建的影响具有明显的尺度依赖性,多样性促进种在中小尺度（0-36 m）上比例最高,在群落多样性构建过程中起主导作用;而中性种在大尺度上比例最高,决定了群落多样性格局的构建过程。因此,多样性促进种和中性种共同影响着局域群落多样性格局构建,二者的相对作用大小取决于讨论问题的空间尺度。

Understanding the effects of species on diversity assembly of local community from the perspective of plant population contributes to revealing the effect of interspecific interactions on the community assemblage,which would be likely covered when discussing at the community levels. The effects of specific species on local diversity patterns were studied at different spatial scales. And the relative contributions of diversity accumulators,neutrals and repellers to community diversity assembly were also examined. On the basis of a 5. 2 hm2 research plot established in a secondary Populus davidiana-Betula platyphylla forest,individual species-area relationship model was used to calculate the ISAR and mI SAR curves of 29 tree species. The complete spatial randomness method was used to test the significance of deviation of individual species-area relationship from the neutral patterns. Our results indicated that the effects of different tree species on local community diversity differ at varying spatial scales. Abies nephrolepis,Acer barbinerve,Acer mono,Populus davidiana,Sorbus alnifolia and Tilia amurensis are diversity accumulators in the research plot. Betula platyphylla and Ulmus davidiana var. japonica arediversity repellers. Fraxinus mandshurica,Quercus mongolica,Malus baccata,Syringa reticulata var.mandshurica are neutrals while other tree species are diversity accumulators at small spatial scales. A significant scale-dependent effect was derived from the influences of diversity accumulators,neutrals and repellers on the assembly of community diversity. The largest proportion of diversity accumulators was found in the medium and small scales of 0- 36 m,and they determined the diversity assembly in forest community. In contrast, neutral species shared the highest proportion and dominated the diversity assembly of forest community at larger scales. Therefore,diversity accumulators and neutrals together spatially structured community diversity assembly; however,the relative effects of them depended on the spatial scales of discussed issues.