生态学报2017，Vol.37Issue(7)：2290-2299,10.DOI:10.5846/stxb201512072446
亚高寒草甸植物群落种多度分布关系及相似性对氮磷添加的响应
Responses of species abundance distribution and community similarity to nitrogen and phosphorus additions in a subalpine meadow
摘要
Abstract
Nitrogen (N) and phosphorus (P) addition can cause species richness loss in grassland ecosystems.However,few studies have reported the changes in species abundance distribution (SAD) patterns and the development direction of plant communities after fertilization.In the present study,for 4 years,a randomized block design experiment,using N and/or P fertilizers at different concentrations,was conducted in a subalpine meadow in Qinghai-Tibet.With data from the fourth year observation,we analyzed the effects of N,P,and N+P additions on species richness,SAD,and community similarity.We also evaluated the contributions of species richness and plant growth form on community structure and species abundance.Results indicated that within the N or N + P addition treatments,community species richness significantly decreased (P＜0.001),the slope of SAD patterns tended to be steeper with higher levels of N addition after four years of treatment.The community species richness and SAD curve responses were more significant in treatments with combined N+P addition than in those with only N addition.For example,in plots with N supply,mean species richness was 44 at an N level of 5 g/m2,33 at 10 g/m2,and 30 at 15 g/m2.In contrast,in plots with N+P supply,mean species richness values were 37,29,and 16 at the three N+P addition levels,respectively.Plots with 15 g/m2 N+P addition showed the largest extent in species richness loss,which could be 65.5％ of the mean control plot species richness.Another result was that in plots with the same resource (single N or combined N+P) addition,vegetation composition diverged among treatments with different N concentrations,whereas vegetation composition converged between treatments with the same N concentrations (stress level =0.152).Furthermore,in the N and N+P addition plots,gramineous plants with brushy roots and caespitose stems gradually became dominant.In contrast,plants with the characteristic of rosette-like leaves,and straight branches,stems,rhizomes,and roots gradually decreased in the plant community.In addition,the responses of community species richness,SAD curves,and community similarity to P addition were not significant (P＞ 0.05).Finally,56.97％ of SAD could be explained by differences in plant growth forms and changes of species richness,induced by the different treatments.Species richness was positively related to plants with rosette-like leaves and rhizomes,but a remarkable negative correlation existed between species richness and plants with brushy roots and caespitose stems.These results suggest that N addition induces a series of changes in plant community composition.These changes include species loss and rearrangement,dominant species turnover and changes of relative abundance of community species (i.e.,a change in the slope of the SAD curve).Furthermore,communities tend to be more similar at the same level of N supply,and more divergent at different levels of N addition.Under the condition of N accumulation,P addition could promote the use efficiency of N,and this effect can be amplified with increasing concentrations of N supply.Overall,the community structure was affected by multiple resources and resource supply levels in this subalpine meadow.关键词
青藏高原/氮磷添加/物种丰富度/生物多样性/群落结构/生长型Key words
Qinghai-Tibetan Plateau/N, P additions/species richness/biodiversity/community structure/growth forms引用本文复制引用
杨莹博,白荣,李爽,李忠明,李海伟,沈禹颖..亚高寒草甸植物群落种多度分布关系及相似性对氮磷添加的响应[J].生态学报,2017,37(7):2290-2299,10.基金项目
国家自然科学青年基金项目(31601984,41101524) （31601984,41101524）
国家公益性行业科研专项(201203006) （201203006）
教育部长江学者和创新团队发展计划资助项目(IRT13019) （IRT13019）
中央高校基本科研业务费专项资助项目(lzujbky-2012-08,lzujbky-2015-191) （lzujbky-2012-08,lzujbky-2015-191）
