全球变暖对植物群落结构及其功能有重要影响.草地生态系统的植物群落对变暖响应极为敏感,但其响应却表现出极大的不确定性.本文通过开顶式气室(Open top chamber,OTC)模拟增温实验,系统研究了科尔沁沙质草地植物群落对增温的响应.结果表明:(1)增温使黄蒿(Artemisia scoparia)和糙隐子草(Cleistogenes squarrosa)的比重分别显著增加了 0.04和0.14,使狗尾草(Setaria viridis)的比重显著降低了 0.12,改变了植物群落组成;(2)增温显著降低沙质草地植物物种丰富度、Simpson指数、Shannon-Wiener指数,且使植物群落、一年生和多年生草本植物的地上生物量分别显著减少22.71％、26.37％和20.10％;(3)增温改变沙质草地的关键类群和主要植物种间关系,使主要科植物间的相互作用减弱、连通性增加,导致植物群落结构稳定性下降;(4)沙质草地植物物种丰富度、Shannon-Wiener指数、生物量与土壤温度呈显著负相关,与土壤湿度呈显著正相关.总之,沙质草地植物群落对增温响应十分敏感,增温驱动的土壤水分及温度变化不仅降低了植物多样性,导致生物量下降,还会加剧沙质草地退化及其生态功能的下降.
Response of plant community to experimental warming in Horqin Sandy Land
Climate warming has important implications for plant community structure and function.Sandy grass-lands are particularly vulnerable to global warming in arid and semi-arid regions.Here,we investigated the ef-fects of experimental warming on plant communities in Horqin Sandy Land of Inner Mongolia,northern China.The results showed that experimental warming had significant impacts on plant community composition.Experi-mental warming caused a rapid increase in the proportion of Artemisia annua and Cleistogenes squarrosa,but a decrease in that of Setaria viridis.The warming significantly reduced species richness,Shannon-Wiener diversity index and Simpson diversity index,as well as the aboveground biomass of entire plant communities,annual and perennial herbs by 22.71％,26.37％and 20.10％,respectively.Network complexity of plant communities de-creased under warmed conditions.In conclusion,plant communities are very sensitive to global warming in Horqin sandy land.The declines in plant diversity and vegetation biomass caused by climate warming likely exac-erbate the degradation of sandy grassland and the decline of ecological functions.
NETL
NSTL
万方数据
维普
