放牧和土壤水分对温性草甸草原群落结构及植被碳库的影响

Effects of Grazing and Soil Moisture on Community Structure and Vegetation Carbon Pool in Warm Meadow Steppe

以辉河保护区天然牧草地、盐碱地和沼泽草地为对象,通过野外调查采样结合室内分析研究放牧影响下不同土壤水分梯度草地的植物群落结构、生物量及碳储量变化。结果显示:植被群落结构受放牧影响较小,放牧与围封条件下的草地物种数相差甚微,群落结构与土壤水分关系密切,物种数随土壤水分增加而减少;放牧、土壤水分和二者的交互作用对地上生物量及其碳储量影响不显著,但对地下生物量及其碳储量产生了显著影响(P<0.05),放牧、土壤水分和二者的交互作用极显著影响0~10 cm地下生物量及其碳储量(P<0.01),土壤水分和二者的交互作用极显著影响10~20 cm地下生物量及其碳储量(P<0.01),土壤水分显著影响20~30 cm地下生物量及其碳储量(P<0.05);不同样地地上生物量碳储量在23.52~70.47 g C/m^(2)之间,地下生物量碳储量在143.30~1750.07 g C/m^(2)之间,地下生物量碳储量远高于地上生物量碳储量,说明地下植被碳库占据植被碳库的主导地位,放牧对植被碳库的影响会在土壤水分条件变化的情况下发生转变。

In this study,the changes of vegetation community characteristics,biomass and carbon storage in natural grassland,saline-alkali grassland and swamp grassland of Huihe Nature Reserve under the influence of different soil moisture gradients and grazing were studied by field survey and sampling combined with laboratory analysis methods.The results showed that the vegetation community structure was less affected by grazing,and there was little difference in the number of species between grazing and enclosure.The community structure was closely related to soil moisture,and the number of species decreased with the increase of soil moisture.Grazing,soil moisture and their interaction had little effect on aboveground biomass and carbon storage,but had significant effect on underground biomass and carbon storage(P<0.05).Grazing,soil moisture and their interaction had a significant impact on underground biomass and carbon storage in 0~10 cm soil layers(P<0.01),and soil moisture and their interaction had a significantly impact on underground biomass and carbon storage in 10~20 cm soil layers(P<0.01),soil moisture significantly affected the underground biomass and carbon storage in 20~30 cm soil layer(P<0.05).The carbon storage of aboveground biomass was 23.52~70.47 g C/m^(2),and the carbon storage of underground biomass was 143.31~1750.07 g C/m^(2).The carbon storage of underground biomass was much higher than that of aboveground biomass,indicating that the carbon pool of underground vegetation played a dominant role in the carbon pool of vegetation,and the effect of grazing on the carbon pool of vegetation would change with the change of soil moisture.