Abstract:In order to understand the impact of climate warming on species diversity of understory vegetation, the effects of short-term 4-year warming (4℃) on understory vegetation diversity in subtropical evergreen broad-leaved natural forest were studied by means of soil warming. The results showed that short-term warming had no significant effect on the species composition of understory vegetation (P>0.05). There were 77 common species in understory vegetation, belonging to 38 families and 59 genera, including 65 species 53 genera and 37 families in warming plot and 63 species 52 genera and 36 families in control plot. Short-term warming increased the coverage of trees by 22.61%, and decreased the coverage of herbs and shrubs by 4.97% and 21.75%, respectively, and warming reduced the height of herbs, shrubs and trees by 21.64%, 3.37% and 5.59%, respectively. The ranking of importance value of ferns in herbaceous plants decreased after warming, and the importance value of trees increased (P>0.05). Although there was no significant difference in species diversity indexes after warming (P>0.05), they all decreased with warming. Therefore, the species composition of understory vegetation was not sensitive to short-term warming, which decreased the importance value of ferns in herbaceous plants and negatively affected the species diversity indexes. However, this response was not sensitive, and it was predicted that long-term warming might lead to the succession of the whole community from herbaceous to shrub and tree.