探究库布齐沙漠黄河沿岸不同防护林配置模式对林下植被多样性的影响,为优化沙区植被配置、提升人工林管理效果及巩固防沙治沙成效提供参考依据。以库布齐沙漠黄河沿岸的5种防护林配置模式[小叶杨+樟子松混交林(XZ)、小叶杨+柠条混交林(XN)、小叶杨+羊柴混交林(XY)、小叶杨+花棒混交林(XH)、小叶杨+花棒+沙柳混交林(XHS)]为研究对象,通过对林下植被群落物种组成的实地调查,应用丰富度指数(R)、Shannon-Wiener多样性指数(H')、Simpson优势度指数(D)和Pielou均匀度指数(J)分析不同配置模式下林下植被多样性特征。结果表明:1)研究区植物种类相对有限,共记录到8科18属20种植物,其中豆科、禾本科和苋科植物占主导地位;2)XN和XH配置模式显著促进林下灌木群落的演替; XHS配置模式对林下草本层的演替更为有利;3)XZ配置模式下的生物量最高,而XHS配置模式的生物量最低,表明不同配置模式对群落有机质积累和生产力具有显著影响,其中XZ模式在提升群落生产力方面更为有效;4)乔木胸径、树高、冠幅等林分因子与林下灌木和草本植物的多样性指数、盖度及密度之间存在显著相关性。通过合理调整乔木层结构,可有效改善林下植被的生长状况和多样性,从而进一步优化人工林的生态功能。

To investigate the effects of different protection forest allocation modes on the diversity of understory vegetation along the Yellow River in the Hobq Desert,in order to provide a reference basis for optimising the planting patterns,improving the management effect of plantation forests in sandy areas,and consolidating the effectiveness of sand prevention and sand control.Five types of planting patterns of forest shelterbelts along the Yellow River in the Hobq Desert were used as the research objects[Populus simonii+Pinus sylvestris var.mongholica mixed forest(XZ),Populus simonii+Caragana korshinskii mixed forest(XN),Populus simonii+Corethrodendron lignosum mixed forest(XY),Populus simonii+Corethrodendron scoparium mixed forest(XH),and Populus simonii+Corethrodendron scoparium+Salix psammophila mixed forest(XHS)],and the under-forest vegetation communities were surveyed for species compositions by the application of the richness index(R),Shannon-Wiener diversity index(H'),Simpson dominance index(D)and Pielou evenness index(J)to analyse the diversity characteristics of the under-forest vegetation under different planting patterns.1)Plant species were relatively limited in the study area,with a total of 20 plant species in 8 families and 18 genera recorded,of which Fabaceae,Poaceae and Amaranthaceae dominated.2)The XN and XH modes significantly promoted the succession of under-forest shrub communities;XHS mode was more conducive to the succession of under-forest herbaceous layer.3)The highest biomass was found in the XZ mode,whereas the lowest was found in the XHS mode.This indicated that different configuration modes had significant effects on the organic matter accumulation and productivity of the community,with the XZ mode being more effective in improving the productivity of the community.4)There were significant correlations between stand factors,such as tree diameter at breast height(DBH),tree height(TH),crown spread(CR),and the diversity indices,cover,and density of the shrubs and herbaceous plants.By reasonably adjusting the structure of the tree layer,the growth and diversity of under-forest vegetation can be effectively improved,thus further optimising the ecological function of plantation forests.