百山祖国家公园植物群落α和β多样性对海拔梯度的响应

αandβdiversity patterns of woody plant communities along an elevation gradient in Baishanzu National Park

物种多样性对海拔梯度的响应是全球气候变化背景下生态学研究的热点。为探究钱江源-百山祖国家公园百山祖园区(以下简称百山祖国家公园)内的植物群落物种多样性沿海拔梯度的变化规律,采用样带法在百山祖国家公园设置一组三条连续海拔梯度样带,连续海拔垂直样带相较非连续海拔分布的样地具有更多的优势,它具有更精确的检测能力和更灵敏的检测手段,能够更好的对任意海拔位置上物种、群落和生物多样性的变化及其机制进行研究。所建设样带宽30 m,总长3210 m,海拔范围为636.3—1928.04 m,总面积为9.63 hm^(2),在样带中进行植物群落每木调查。调查样带内所有胸径≥1 cm的木本植物个体,记录种名、胸径等,分析植物群落α和β多样性对海拔梯度的响应。结果表明:在三条样带上,共记录木本植物260种、69914个个体,隶属于55科109属。物种丰富度、Shannon-Wiener指数、Simpson指数、Pielou指数与海拔梯度均呈显著负相关关系。地形因子中海拔对物种α多样性影响最大,坡度次之,坡向对α多样性影响较小。随着样地间海拔距离的增大,样地间β多样性指数(Jaccard相似性指数)都与样地间海拔距离呈显著的负相关关系,即群落的Jaccard相似性指数随着样地间海拔距离的增大而减小,植物群落β多样性与海拔、坡度、坡向均呈显著的相关关系,其中海拔的影响最大,坡度次之,坡向的影响较小。在海拔梯度上物种β多样性的周转组分占主导地位,各植物群落物种组成差异由物种更替控制。研究结果为今后百山祖国家公园及其他亚热带山地生物多样性保护、山地生态系统多样性和稳定性维持政策制定提供了科学依据。

The response of species diversity to elevation gradients is a hot topic in ecological research under global climate change.The objective of this study is to investigate the variation of plant community species diversity along the elevation gradient in the Baishanzu Park Area of Qianjiangyuan-Baishanzu National Park(hereinafter referred to as Baishanzu National Park).The study adopted the transect method and set up a group of three continuous elevation gradient transects in Baishanzu National Park.Continuous vertical transects had more advantages than discontinuous elevation distribution.With more accurate detection capabilities and more sensitive detection methods,we could better study the changes and mechanisms of species,community and biodiversity at any altitude.The three transect-zones covered typical ecosystem types at various elevations in the park,while avoiding areas with frequent human and animal activities and areas with unstable soil matrix.In order to facilitate long-term monitoring in the future,the transshipment was constructed in accordance with domestic and foreign norms of forest dynamic monitoring sampling survey.The bandwidth of the constructed sample was 30 m,the total length was 3210 m,the elevation was 636.3 m to 1928.04 m,and the total area was 9.63 hm^(2).The responses ofαandβdiversity of plant communities to the elevation gradient were analyzed through the species names and diameter at breast height(DBH)of all woody plants≥1 cm in the transect.The results showed that a total of 69914 individuals of woody plants belonging to 260 species,109 genera,and 55 families were recorded in the three transects.Species richness,Shannon-Wiener diversity index,Simpson dominance index and Pielou evenness index were negatively correlated with elevation.Among topographic factors,elevation had the greatest effect onαdiversity,followed by slope,and aspect had little effect onαdiversity.The Jaccard similarity index was significantly negatively correlated with the elevation distance between sample plots,that is,the Jaccard similarity index of the community decreased with the increase in the elevation distance between sample plots,whileβdiversity was significantly correlated with elevation,slope and aspect,in which elevation had the greatest effect,followed by slope,and aspect had little effect.The turnover component of speciesβdiversity(Jaccard dissimilarity index)was larger than the nested component on the elevation gradient,that is,the turnover component was dominant on the elevation gradient,and the differences in species composition among plant communities were controlled by species replacement.The results provide a scientific basis for the future policy formulation of biodiversity conservation and stability maintenance of mountain ecosystems in Baishanzu National Park and other subtropical mountainous areas.