黄土高原东部山地林下不同植物功能群地上生物量对模拟增温的响应

Responses of aboveground biomass for different plant functional groups to experimental warming in a mountain forest in the eastern Loess Plateau,China

气候变暖在山地尤为明显,山地林下草本群落对气候变暖的响应成为草地生态系统研究的新方向。文中以黄土高原东部山地林下草本群落为研究对象,采用开顶式生长室进行模拟增温实验,设置对照、低度增温和高度增温3种实验处理,探究黄土高原东部山地林下草本群落水热因子和不同植物功能群地上生物量对模拟增温的响应。结果表明:1)在增温处理下,空气温度分别增加0.23℃和0.83℃,空气湿度分别增加1.06%和1.82%,土壤湿度分别减小0.54%和2.10%,但土壤温度在低度增温处理下减小0.10℃,在高度增温处理下增加0.09℃。2)莎草地上生物量分别增加7.34g/m^(2)和4.28g/m^(2),杂草地上生物量分别增加12.27g/m^(2)和10.34g/m^(2),但禾草地上生物量在低度增温处理下减小1.05g/m^(2),在高度增温处理下增加3.46g/m^(2)。3)不同植物功能群地上生物量与温度的相关系数绝对值分别增加105.92%和150.51%,与水分的相关系数绝对值分别增加20.73%和42.28%。综上,增温改变了黄土高原东部山地林下草本群落的水热条件,导致草本群落不同植物功能群发生改变,使之朝向杂草植物进行演替。研究有助于理解山地草地生态系统对气候变暖的响应机制,为黄土高原地区生态环境保护和可持续发展提供科技支撑。

Climate warming is particularly evident in mountainous areas,and the response of understory herbaceous communities to climate warming has become a new focus for grassland ecosystem research.In this research,the understory herbaceous communities in the Lvliang Mountains located in the eastern part of the Loess Plateau were taken as the research object,an open-top growth chamber was employed for a controlled warming experiment,three treatments were established:control,low,and high temperature warming scenarios.This set-up aimed to investigate how hydro-thermal conditions and the aboveground biomass of distinct plant functional groups in the understory of the eastern Loess Plateau’s mountainous regions respond to simulated temperature elevation.The results showed that:1)under the warming treatments,air temperature increased by 0.23℃and 0.83℃,respectively.The air humidity increased by 1.06%and 1.82%,respectively.Soil moisture decreased by 0.54%and 2.10%,respectively.The soil temperature decreased by 0.10℃under OTC1 treatment,but increased by 0.09℃under OTC2 treatment.2)Aboveground biomass of sedge increased by 7.34g/m^(2)and 4.28 g/m^(2),respectively.Aboveground biomass of weeds increased by 12.27g/m^(2)and 10.34g/m^(2),respectively.Aboveground biomass of grass decreased by 1.05g/m^(2)in OTC1 treatment,but increased 3.46g/m^(2)in OTC2 treatment.3)The absolute value of the correlation coefficient between aboveground biomass of different plant functional groups and temperature increased by 105.92%and 150.51%,respectively,as well as that between aboveground biomass of different plant functional groups and moisture correspondingly increased by 20.73%and 42.28%,respectively.In conclusion,warming changed the hydrothermal conditions of understory herbaceous communities in the eastern mountainous areas of the Loess Plateau,resulting in changes in different plant functional groups of herbaceous communities,leading to a succession towards weed species.This study is helpful to understand the response mechanism of mountain grassland ecosystem to climate warming,and provide scientific and technological support for ecological environment protection and sustainable development in the Loess Plateau.