太行山森林群落物种多样性空间格局及其影响因素

Spatial patterns of and factors influencing species diversity in the forest communities of China’s Taihang Mountains

探索物种多样性的地理分布格局一直是生物地理学和宏观生态学的核心议题之一.以太行山为研究区域,基于309个植物群落的野外调查数据,分析不同生活型植物物种多样性随海拔和纬度的变化规律及其影响因素.结果显示:(1)太行山森林群落以草本植物物种多样性占绝对优势,而乔木植物的均匀度指数最高;(2)随海拔的升高,物种丰富度指数和多样性指数呈显著上升趋势,其中草本植物和乔木植物与总物种变化趋势一致,灌木植物无显著变化,而均匀度指数则无明显的海拔格局;(3)在纬度格局方面,随纬度的升高群落总物种和草本植物的丰富度指数呈先减后增的变化趋势,草本植物的物种多样性指数和均匀度指数均呈增加的趋势,而灌木植物和乔木植物无明显的纬度格局;(4)地形因素中的海拔因子和气候因素中的年平均温度因子是影响群落物种丰富度的关键因子,且不同生活型植物的主要影响因子有一定差异,而干扰因子对各生活型物种丰富度的影响均不显著.方差分解结果显示地形、气候和干扰因子整体上对群落物种丰富度具有较高的解释率,对草本、灌木、乔木和所有物种的总解释率分别是61.6%、32.9%、40.6%和50.5%,其中气候因子和地形因子是影响不同生活型物种丰富度的主要解释变量.本研究表明气候和地形是影响区域尺度森林群落物种多样性空间格局的主要成因,但对不同生活型物种的影响仍存在一定差异.(图5表2参48)

Exploring the geographic distributions of species has long been a challenge in biogeographical and macroecological research.Previous field surveys have shown that the Taihang Mountains of northeastern China support 309 plant communities.We used data from these surveys to analyze changes in plant diversity at various altitudes and latitudes,and to identify the primary factors determining species distributions within the mountain range.The results of this analysis showed that(1)forest communities in the Taihang Mountains are dominated by herbaceous plant species,with tree evenness the highest of all plant types.(2)Species richness and diversity increased significantly with altitude;herbaceous plants and arbors exhibited the same overall trend as that for all species combined,whereas no significant changes were detected for shrubs.Moreover,no clear trends were observed in species evenness at different altitudes.(3)Total and herb species richness initially decreased but then increased with increasing latitude.Among herbs,species diversity and evenness increased with latitude,but no clear pattern was observed for shrubs and arbors.(4)Altitude and annual mean temperature were found to be the key topographical and climatic factors influencing forest species richness,respectively,and the main factors determining differences in plant life forms.However,disturbance factors had no significant impacts on plant life-form richness.Variance breakdown revealed that topographical,climatic,and disturbance factors primarily accounted for whole-community species richness,with total explanatory rates for herbs,shrubs,arbors,and all species of 61.6%,32.9%,40.6%,and 50.5%,respectively.Climatic and topographical factors were the main variables affecting life-form richness.Overall,the results of this study reveal climatic and topographical factors to be the primary drivers of species diversity spatial patterns in forest communities at the regional scale,but impacts vary considerably among different life forms.