北京市湿地入侵植物群落与本地植物群落的生物多样性比较

Comparisons of the biodiversity of invasive alien plant community and native plant community in Beijing wetlands

为明确外来入侵植物对本地湿地植物多样性的影响,在北京市湿地选择23个样地共245个样方进行物种多样性调查,并从不同植物性状数据库获取样方中所有植物的株高、叶长、叶宽、叶面积和比叶面积等10个功能性状数据,对比分析入侵群落与本地群落的物种多样性、系统发育多样性和功能多样性特征。结果显示,在北京市湿地共记录到26种外来入侵草本植物,隶属10科19属,其中,菊科外来入侵植物种类最多,有10种。除比叶面积、叶片碳含量和株高的系统发育信号显著外,其余7种植物功能性状的系统发育信号均不显著,表明大多数功能性状未表现出系统发育保守性。入侵群落所有物种的物种多样性指标Shannon-Wiener多样性指数、物种丰富度指数和Simpson优势度指数以及系统发育多样性指标谱系多样性和平均最近谱系发育距离均显著高于本地群落和入侵群落本地物种,而入侵群落本地物种的功能分散指数和Rao′Q二次熵指数均显著高于本地群落,表明外来物种入侵改变了湿地植物的生物多样性,且外来物种入侵后群落谱系多样性趋于发散,说明与本地植物亲缘关系越远的入侵物种越容易在湿地群落中建立种群,符合达尔文归化假说。

To clarify the impacts of invasive alien plants on the diversity of native plants in wetland,245 plots in 23 sites were investigated for the plant biodiversity in Beijing wetlands,and ten plant functional traits data such as plant height,leaf length,leaf width,leaf area,and specific leaf area of all plants were collected from different plant trait databases.Taxonomic diversity,phylogenetic diversity,and functional diversity of both invasive alien and native plant communities were analyzed.The resulted showed that a total of 26 invasive alien plants were recorded belonging to 19 genera,ten families.Among them,Asteraceae had the highest number with ten species.Only specific leaf area,leaf carbon content and plant height showed significant phylogenetic signals,and the other seven plant functional traits were not significant,indicating that most functional traits did not exhibit phylogenetic conservatism.In terms of taxonomic diversity,the Shannon-Wiener diversity index,species richness index,and Simpson dominance index of all plants in invasive community were significantly higher than native community and native plants in invasive community.In terms of phylogenetic diversity,phylogenetic diversity and the mean nearest taxon distance metrics of all plants in invasive community were significantly greater than native community and native plants in invasive community.Regarding functional diversity,both the functional dispersion index and Rao′Q quadratic entropy index demonstrate higher values for native plants in invasive community when compared with native community.Moreover,the community phylogenetic diversity tends to diverge after the invasion of alien species,indicating that invasive alien species with farther distance relative to native plants are more likely to establish populations in wetland communities,which is in line with the Darwin naturalization hypothesis.