为了探究若尔盖高原湿地水质演变特征及氮磷累积效应,2016—2018年以若尔盖高原湿地植被多样性为基础数据,通过野外调查和室内化验相结合的模式,并结合冗余分析(RDA)的方法研究了植被多样性、氮磷累积特征与水质之间的关系。结果 表明:(1)2016—2018年若尔盖高原湿地植被Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数和Simpson优势度指数随季节均表现为先增加后降低趋势,夏季和秋季明显高于春季和冬季。(2)若尔盖高原湿地不同年份水质中TN、NH+4-N、TP、高锰酸钾指数、BOD5和CODcr浓度总体变化趋势相一致,均为秋季最高,夏季次之,春季最低,随季节变化呈先增加后降低趋势。TN、NH+4-N、高锰酸钾指数、BOD5和CODcr浓度均值在不同年份差异均显著(p<0.05),而TP浓度在不同年份和不同季节差异均不显著(p>0.05)。(3)若尔盖高原湿地植被N,P积累量随季节变化呈先增加后降低趋势。2016—2018年N,P累积量均值呈增加趋势,其中N累积量均值在不同年份差异均显著(p<0.05),而P累积量在不同年份和不同季节差异均不显著(p>0.05)。(4)若尔盖高原湿地植被N,P积累量分别与生物量、N、P含量呈显著的线性关系(p<0.05),由此可知,可以通过植被N,P含量和生物量评价湿地植被的N,P累积作用。RDA排序图显示BOD5浓度、CODcr浓度是若尔盖高原湿地植物多样性的主要影响因素。
In order to explore the water quality evolution and effect of nitrogen and phosphorus accumulation in wetland of Ruoergai Plateau, the evolution characteristics of water quality and the accumulation effect of nitrogen and phosphorus were studied by field survey and laboratory test from 2016 to 2018, and the relationship between vegetation diversity and water quality was studied by using the method of redundant analysis(RDA). The results showed that:(1)the Margalef richness index, Shannon Wiener diversity index, Simpson dominance index and Pielou evenness index firstly increased and then decreased with the change of seasons, and those indices in autumn and summer were significantly higher than those in spring and winter(p<0.05);(2)TN, NH+4-N, TP, potassium permanganate index, BOD5 and CODcr concentrations in water quality showed the consistent change trend with seasons, which were the highest in autumn, followed by summer, and the lowest in spring; TN, NH+4-N, potassium permanganate index, BOD5 and CODcr concentrations showed thesignificant differences in different years (p<0.05), while TP had no significant differences in different years and seasons (p>0.05);(3)the accumulation of N and P had the obvious consistent patterns, which were the highest in autumn, followed by summer, and the lowest in spring; the mean accumulation of N and P showed an increasing trend from 2016 to 2018, and the mean accumulations of N were significantly different in different years (p<0.05), while the mean accumulations of P had no significantly difference in different years and seasons (p>0.05);(4)there was a significant linear relationship between the accumulations of N and P and the biomass, N and P contents, respectively (p<0.05); therefore, the accumulations of N and P could be evaluated through the biomass and N and P contents. RDA sequence diagram showed that BOD5 and CODcr concentrations were the main factors influencing wetland plant diversity in Ruoergai Plateau.
