生长季封育和氮添加对退化高寒沼泽湿地土壤水分状况的影响

Responses of Soil Water Content of Degraded Alpine Wetland to Growing-Season Fencing and Nitrogen Addition

为探讨封育和氮添加对退化高寒湿地恢复的影响,本研究在青藏高原东部轻中度退化高寒湿地设置生长季禁牧和氮添加处理试验,并测定了群落结构和生产力、物种丰富度、土壤水分和氮、磷元素含量等指标。结果表明生长季禁牧能够显著提高退化湿地土壤水分含量、土壤速效氮含量和群落净初级生产力,提高禾草类物种在群落中的占比,而降低杂类草物种的占比;氮添加及二者的交互作用对退化湿地植物群落上述指标的影响不显著,但是氮添加处理有增加地上生物量和提高土壤含水量的趋势。本研究还提出了一个围栏封育和氮添加对退化高寒湿地恢复(以土壤水分含量为指标)影响的概念模型。生长季禁牧和氮添加有助于高寒退化湿地的恢复,因此在未来高寒湿地的保护和修复中应该考虑适度禁牧和养分添加。

In order to understand the effects of fencing and nitrogen addition on restoration of alpine wetlands,we conducted an experiment in a moderate degraded alpine wetland,located at eastern part of Qinghai-Tibetan Plateau.The structure,species richness and productivity of community,as well as soil properties were measured.Our results showed that growing season fencing could significantly increase soil water content(SWC),soil available nitrogen(AN)content,community net primary productivity(NPP)and proportion of grass species,while decrease proportion of forbs.There were no significant effects of nitrogen addition and its interaction with fencing on these indices of soil and community,similar patterns were also found for effects of nitrogen addition on NPP and SWC.A simple framework model was proposed to explain how fencing and nitrogen addition directly or indirectly affected the restoration of degraded alpine wetland(indicated by SWC).Our finding suggested that both growing season fencing and nitrogen addition could promote restoration processes of degraded alpine wetland,implying that these management strategies should been considered for protection and restoration of alpine wetland in the context of future climatic and anthropogenic environment changes.