山东刺槐林对林下植物物种多样性及谱系多样性的影响

Impacts of black locust forest on understory plant species diversity and phylogenetic diversity in Shandong Province

刺槐(Robinia pseudoacacia)是一种广泛分布的外来植物,通常认为外来物种会对自然生态系统造成一定影响。然而,刺槐对当地植物多样性的影响仍存在争议。本研究的主要目的是比较刺槐群落和以麻栎(Quercus acutissima)或栓皮栎(Q.variabilis)为优势种的本地落叶栎群落林下植物物种组成、物种多样性、谱系多样性及群落谱系结构的差异,探究刺槐林对当地森林生态系统可能造成的影响。在山东丘陵区设置17个刺槐群落和17个相应的落叶栎群落样方(样方大小为20 m×30 m),调查每个样方内林下植物物种组成和多样性情况。研究发现,刺槐群落与落叶栎群落林下植物物种和谱系α多样性并无显著差异,而刺槐群落林下物种和谱系β多样性显著低于落叶栎群落,且刺槐群落植物谱系距离随环境距离的变化速率低于落叶栎群落,刺槐各样方间共有物种比例较大,物种的生态位较为相似,表明刺槐导致了植物群落的均质化。另外,刺槐群落较落叶栎群落具有较高的外来物种丰富度。可见,山东刺槐林虽然对植物物种数量没有显著影响,但却改变了群落的组成和结构。应对刺槐林进行长期监测,有效防控外来植物对当地生态系统造成的威胁。

Black locust is a widespread alien species,which is considered to influence natural ecosystems.However,its effects on plant species diversity in forests are still controversial.Here,we compared species composition,species diversity,phylogenetic diversity and phylogenetic structure between black locust community and native deciduous oak community dominated by Quercus acutissima or Q.variabilis,to clarify the impacts of black locust.A total of 17 black locust communities and 17 corresponding native oak communities(with plot size of 20 m×30 m for each)were selected in the hilly areas of Shandong Province,China.We measured understory plant species composition and diversity.There was no significant difference in species and phylogeneticαdiversity between black locust community and native oak community.The species and phylogeneticβdiversity in black locust community were lower than that in deciduous oak community.The decay rate of phylogenetic similarity was lower in black locust community than in deciduous oak community,indicating that plant species had close phylogenetic relationships in black locust communities.Black locust led to more homogenous understory communities.In addition,black locust community had higher alien species richness than native oak community.While black locust did not affect plant species richness,it changed the structure and composition of plant community.Long-term monitoring of black locust forests should be carried out to effectively control the threat from exotic plants to local ecosystems.