模拟N沉降对太岳山油松人工林和天然林草本群落的影响  

Effect of simulation N deposition on herbaceous vegetation community in the plantation and natural forests of Pinus tabulaeformis in the Taiyue Mountain

作　　者：李化山[1] 汪金松[2] 刘星[1] 王娜[1] 赵博[1] 张春雨[1] 赵秀海[1] 

机构地区：[1]北京林业大学森林资源与生态系统过程北京市重点实验室,北京100083 [2]中国林业科学研究院森林生态环境与保护研究所,北京100091

出　　处：《生态学报》2015年第11期3710-3721,共12页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31340022);国家林业公益性行业科研专项(201104009)

摘　　要：由于人类活动氮沉降呈逐年增加的趋势,进而增加了陆地生态系统氮的输入,从而影响陆地生态系统多样性、物种组成和功能。为揭示氮沉降增加对油松林草本群落的影响,于2009年7月在太岳山油松人工林和天然林,设计4个施氮水平:对照(CK,0 kg N hm-2a-1),低氮(LN,50 kg N hm-2a-1),中氮(MN,100 kg N hm-2a-1)和高氮(HN,150 kg N hm-2a-1),研究草本群落的生物多样性、生物量以及草本元素含量对模拟N沉降的响应。研究结果表明:模拟N沉降未能显著影响人工林草本群落的生物多样性(P>0.05),而中氮、高氮显著降低了天然林草本群落的生物多样性(P<0.05);从Jaccard指数和Sorensen指数分析得出人工林不同氮水平之间草本群落差异性较小,而天然林不同氮水平之间草本群落差异性较大。模拟N沉降没有显著改变人工林草本群落生物量(P>0.05),而高氮明显促进天然林草本群落生物量的增加(P<0.05)。与对照相比,模拟N沉降提高了人工林和天然林羊胡子苔草叶根中的全N含量(P<0.05),而降低了全Mg的含量(P<0.05),并且根部元素含量变化与土壤养分含量变化较为一致。施氮提高了N/K、N/Ca、N/Mg(P<0.05)的比值。说明油松林下草本群落对氮沉降的响应因林分土壤N饱和程度以及林地利用历史的不同而产生差异,其中天然林响应最为敏感。Human activities have significantly altered global and regiona1 cycles of nitrogen（ N） in the last several decades due to combustion of fossil fuels,intensive agriculture and stock breeding. The amount of human-made reactive N which is more than the natural production,released into the atmosphere. Nitrogen（ N） deposition has been widely considered as an environmental problem that leads to destruction of ecological balance such as biodiversity loss,base cation loss,soil acidification,but increases net primary productivity of N-limited forest ecosystems. Greater N deposition has a significantly effect on productivity,plant diversity and biomass allocation of forest ecosystem. To determine the influence of N deposition on species diversity,biomass and nutrients of herbaceous vegetation community,for this： 12,20 m × 20 m plots,respectively,distributed in the plantation and natural forest of Pinus tabulaeformis were established in the Taiyue Mountain,Shanxi Province,since July,2009. Within each stand,equal numbers of 20 m × 20 m plots were treated with four nitrogen fertilization levels： control（ CK,0 kg N hm^-2a^-1）,low nitrogen（LN,50 kg N hm^-2a^-1）,moderate nitrogen（MN,100 kg N hm^-2a^-1） and high nitrogen（HN,150 kg N hm^-2a^-1）,the different levels of N were added at the middle of each month in growing season Since 2009. Herb samples were collected and investigated in August in 2012,and the soil samples were collected in August of 2009 and 2012. The coverage,diversity indices,above- ground biomass,underground biomass,total biomass and element contents of herbaceous vegetation community and soil physical and chemical characteristics of different nitrogen levels were analyzed. Results showed that： Nitrogen additions did not significantly（ P 〉0. 05） affect diversity indices of herbaceous vegetation community in the plantation forest,however,MN and HN treatments significantly decreased the diversity indices（ P〈0. 05） of herbaceous vegetation community in the natural forest.

关 键 词：N沉降 草本 生物多样性 生物量 元素含量 油松 

分 类 号：Q948[生物学—植物学]