短期增温对亚热带常绿阔叶林林下植被物种多样性的影响

Effects of Short-term Warming on Species Diversity of Understory Vegetation in Subtropical Evergreen Broad-leaved Forest

摘要:

为了解气候变暖对亚热带常绿阔叶林林下植被物种多样性的影响，采用土壤增温方式，研究短期4年增温（4℃）对亚热带常绿阔叶天然林林下植被物种多样性的影响。结果表明，短期增温对林下植被物种组成影响不显著（P>0.05），增温和对照样地林下植被共有植物38科59属77种，其中增温样地37科53属65种，对照样地36科52属63种。短期增温使乔木盖度增加了22.61%，草本和灌木盖度分别降低4.97%和21.75%；增温使草本、灌木和乔木的高度分别降低21.64%、3.37%和5.59%。草本植物中的蕨类重要值排名在增温后呈下降趋势，乔木重要值呈上升趋势（P>0.05）。虽然植物物种多样性指数在增温后差异不显著（P>0.05），但随温度增加均呈递减的趋势。因此，林下植被物种组成对短期增温响应不敏感，增温使草本植物中的蕨类重要值下降，对植物多样性指数产生一定负面影响，但这种响应并不敏感，预计长期增温将可能导致整个群落从草本向灌木和乔木方向演替。

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.