摘要
群落谱系结构是了解群落聚群过程的一个基础研究内容。但是现有大部分研究内容集中在群落组成和结构的时空差异,对谱系结构的动态变化研究较少。以浙江省清凉峰国家级自然保护区的国家二级保护植物台湾水青冈(Fagus hayatae)林为研究对象,利用2006年、2011年、2016年3次群落动态调查数据,从10、20、50m的3个空间尺度上研究该群落在10a间的谱系结构动态变化,分析时空尺度对台湾水青冈群落谱系结构的影响,探究调控台湾水青冈群落动态变化的主要因子,为后期台湾水青冈林的保护提供理论基础。研究发现(1)在10a森林动态变化过程中,群落的MPD指数下降,MNTD指数增加。NRI和NTI指数在大尺度上随时间显著增加,但在小尺度上无显著变化。(2)随着空间尺度的增加,上述指数的动态变化趋势均不断增强。以上结果表明,2006—2016年间台湾水青冈群落总体谱系结构表现出不断聚集的趋势,而近缘种的谱系关系则不断疏远;群落谱系结构的聚集趋势随空间尺度的增加而增强。大尺度上的环境过滤和小尺度上的随机过程和种间竞争作用可能是导致该地区台湾水青冈群落谱系结构动态变化的主要生态学过程。
The phylogenetic structure of communities is a fundamental component in our ability to understand community assembly processes and species coexistence. However, although there have been many studies of the spatial and temporal variation in community structure, few have applied these observations to the dynamics of phylogenetic structure. Here, we performed such an analysis to study temporal and spatial variations in the phylogenetie structure of Fagus hayatae communities, Class II protected plant, in China. In 2006, all free-standing woody stems with a diameter at breast height （DBH） ≥1cm were tagged, mapped, identified, and measured for DBH, and height in a 1 hm2 forest dynamic plot in Qingliangfeng National Nature Reserve, China. This was followed by re-censuses in 2011 and 2016, in which we recorded the survival status and DBH for previously recorded stems and documented new stems with DBH ≥1cm. On the basis of these three censuses spread across a decade （2006, 2011, 2016）, we measured the dynamics of the phylogenetic structure at three spatial scales （ 10m, 20m, and 50m）. We used global seed plant phylogenetic data to construct a phylogenetic tree of F. hayatae communities, and selected the mean phylogenetic distance （MPD）, mean nearest taxon distance （MNTD）, net relatedness index （NRI）, and nearest taxon index （NTI） to describe the phylogenetic structure of F. hayatae communities. Additionally, we randomly resampled 999 plots at 10m, 20m, 50m scales using a moving split-window technique to create plots at different spatial scales. Analysis across spatial and temporal scales produced the following results. （ 1 ） On decadal time scales, the species richness and abundance of F. hayatae communities both decreased. MPD decreased, whereas MNTD increased. NRI and NTI both significantly positively increased at large scales, but did not change at small scales. （2） As the spatial extent of analyses increased, so did the strength of the trends observed. Thus, the phylogenetic structure of F. hayatae communities showed a clustering pattern and was spatial scale dependent. The largest variation in the phylogenetic structure across time was found at the 50m scale. We concluded that from 2006 to 2016, the phylogenetic structure of F. hayatae communities was clustering, whereas the phylogenetic relationships between nearest species became more distant. Moreover, the effects of environmental filtering dominated the phylogenetic structure dynamics of F. hayatae communities at large scales. This is in contrast to the effects of stochastic processes and interspecific competition, which dominated at small scales. Against a background of global climate change and forest degradation, further studies on scale dependence are needed to gain a better understanding of the mechanisms of community assembly, and to protect these endangered species.
出处
《生态学报》
CAS
CSCD
北大核心
2018年第4期1320-1327,共8页
Acta Ecologica Sinica
基金
浙江理工大学科研启动项目(13052168-Y)
浙江理工大学"521"人才项目
关键词
浙江清凉峰国家级自然保护区
台湾水青冈
谱系结构
尺度
环境过滤
Zhejiang Qingliangfeng National Nature Reserve
Fagus hayatae
phylogenetic structure
scale
environmentalfiltering
