滇西北高原纳帕海湿地植物多样性与土壤肥力的关系

采用植物群落研究法与原状土就地取样技术,研究了滇西北高原典型退化湿地纳帕海植物多样性、土壤养分、酶活性格局特征及其相互关系.随着湿地原生沼泽向沼泽化草甸、草甸的演替,湿地植物群落盖度增加、物种组成增多,群落优势种优势度减小,伴生种数量增加,植物多样性呈增加趋势;湿地土壤有机质、全氮含量不断减少,过氧化氢酶、蛋白酶、蔗糖酶活性增加,脲酶活性降低.植物α多样性指数(辛普森、香浓-维纳指数)与湿地土壤有机质、全氮含量呈负相关,与土壤过氧化氢酶、蛋白酶、蔗糖酶活性呈正相关,与脲酶活性呈负相关;土壤有机质、全氮含量与过氧化氢酶、蛋白酶、蔗糖酶活性呈一致负相关,与脲酶活性则成正相关.湿地景观在一定程度上反映了人为生产活动干扰的类型与强度,其植物多样性、土壤养分和酶活性特征及其相互关系是湿地生态系统演替过程中时空间体现,研究结果揭示了人为干扰下湿地退化的生态学过程及机理,可为我国高原湿地生物多样性保护,退化湿地生态恢复与湿地资源可持续利用提供一定的理论依据.

Relationship between plant diversity and soil fertility in Napahai wetland of Northwestern Yunnan Plateau

To understand the interactions among soil nutrients, enzyme activities and aquatic plant diversity in a wetland landscape under human disturbances, a three-year study was carried out in the Napahai wetland, a typical degraded plateau wetland in the northwestern Yunnan, China. The plant community composition changed and the community coverage increased over the wetland succession from primary swamp, through swampy meadow, to meadow. The number of associated species increased, while the dominant species abundances decreased. Through succession, the content of soil organic matter and total nitrogen declined. In contrast, the soil enzyme activity of catalase, protease and invertase increased; however urase declined. The Simpson and Shannon-Weiner indices of aquatic plant diversity were both significantly positively correlated with catalase, protease and invertase, and negatively correlated with urase, soil organic matter and total nitrogen. Similarly, soil organic matter and total nitrogen were negatively correlated with catalase, protease and invertase but positively correlated with urase. This wetland succession is thus related to the type and intensity of human disturbances, the characteristics of plant diversity, soil fertility and soil enzyme activity. The results from this study will facilitate understanding of the ecological processes and mechanisms contributing to degraded wetlands subject to anthropogenic pressure, and provide guidelines for the assessment of wetland health, sound environmental management and restoration.