Association distribution characteristics of natural and artificial Larix gmelinii forests along environmental gradients in northeast China
Abstract Background: Larix gmelinii forest is one of coniferous forests in cold-temperate zone, which is a vital part of national strategic landscape of ecological security of China. Plant association distribution is different in natural and artificial Larix gmelinii forests, meanwhile, determining mechanisms in typical associations of Larix gmelinii forests still need to be explored. The study focused on which environmental factors actuated association distribution of natural and artificial Larix gmelinii forests in northeast China. Two-way indicator species analysis (TWINSPAN) and canonical correspondence analysis (CCA) were used to classify plant associations and explored the relationship between species and environment. Results: All the plots (n=175, size=30 m×30 m) of Larix gmelinii forests were classified into 6 plant associations by TWINSPAN. Species diversity in natural forests were higher than that in artificial forests. Ass.III and Ass.IV only appeared in natural forests, meanwhile, Ass.VI only appeared in artificial forests. The primary environmental drivers of species diversity patterns in natural forests were annual mean temperature, followed by annual precipitation, elevation, slope aspect, and canopy density. However, elevation and annual precipitation had strong effects in determining association distribution in artificial forests. Conclusions: Plant association distribution showed habitat preferences, besides, natural forests had higher species diversity and more resistance than artificial forests. The study can be used as a reference for Larix gmelinii forest ecosystem protection in northeast China and a theoretical basis for scientific management in similar areas.