增温对东北温带次生林草本群落季节动态的影响

Effects of simulated warming on seasonal dynamics of herbaceous diversity in temperate secondary forests in Northeast China

主要由人类活动造成的气候变暖导致陆地植物多样性和群落结构发生改变,森林草本层作为森林生态系统植物多样性的主要贡献者,对气候变暖的响应十分显著,而目前仍缺乏相关研究。本研究基于中国科学院清原森林生态系统观测研究站搭建的红外线模拟增温平台,分析了表层土壤(0–10cm)增温2℃条件下林下草本层群落在生长季受到的影响。结果表明:增温第4–5年间,对照和增温处理下的草本植物多样性无显著差异,但增温处理下各季节的多样性指数均较对照处理呈现减小趋势;对照和增温处理下的草本层群落总体盖度和多度无显著差异,但群落组成及结构发生显著改变。不同优势种对增温的响应趋势不同。年优势种中,山茄子(Brachybotrys paridiformis)的响应最显著,其重要值、多度和盖度在各季节均显著增加,而龙头草(Meehania henryi)在各季节显著减少,白花碎米荠(Cardamineleucantha)和荷青花(Hylomeconjaponica)的响应不显著;季节优势种中,春季优势种单花韭(Allium monanthum)重要值显著降低,五福花(Adoxa moschatellina)重要值显著增加,夏季优势种珠芽艾麻(Laportea bulbifera)无显著响应。综上,增温对该区森林草本植物多样性无明显影响,但可能导致某些物种物候期提前,改变群落内物种对光等资源的竞争关系,或者影响某些物种的功能性状,显著改变不同季节部分优势种的重要值、多度和盖度,导致草本层群落组成和结构发生变化。

Aims:Climate warming mainly caused by human activities has led to changes in terrestrial plant diversity and community structure.Forest herb layer,as the main contributor of plant diversity in forest ecosystem,has a significant response to climate warming,however,relevant studies are still lacking.This study explores the changes of herbaceous community in temperate forests in the context of climate warming,including diversity,community structure,and species composition,in order to provide scientific basis for the response of forest herbaceous layer to climate warming.Method:This experiment was carried out in 2021 and 2022 on a simulated warming platform built by Qingyuan Forest Ecosystem Research Station of Chinese Academy of Sciences,which used an infrared ray to warm the surface soil by 2℃during the growing season.Results:The results showed that there was no significant change in herbaceous diversity under warming conditions,but the community diversity index of each season showed a decreasing trend.After warming,the overall coverage and abundance of the herbaceous community did not change significantly,but the composition and structure of the herbaceous community changed significantly.Specifically,the response trend of different dominant species to warming was different.Among the dominant species throughout the year,the response of Brachybotrys paridiformis was the most obvious,as its importance value,abundance,and coverage increased significantly,while that of Meehania henryi decreased significantly.Cardamine leucantha and Hylomecon japonica had no significant response.Lastly,the importance value of Allium monanthum,which is the seasonal dominant species,was significantly decreased,while that of Adoxa moschatellina was significantly increased.Conclusion:Warming has no significant effect on herbaceous diversity in the forest in this study,but it may lead to the advancement of the phenological period of some species,change the competition between species in the community for resources such as light,or affect the development of functional traits of some species.Furthermore,it may change the importance value,abundance,and coverage of dominant species in different seasons,and lead to significant changes in the composition and structure of the herbaceous community.