在發(fā)現(xiàn)氮沉降可能降低熱帶亞熱帶地區(qū)“富氮”森林植物多樣性現(xiàn)象的基礎(chǔ)上（詳見Global Change Biology, 2010, 16: 2688–2700），中科院華南植物園生態(tài)系統(tǒng)管理研究組魯顯楷博士等在莫江明研究員的指導(dǎo)下,，通過在鼎湖山國家級(jí)自然保護(hù)區(qū)6年多野外試驗(yàn)觀察和分析比較,，發(fā)現(xiàn)再造林（reforested forests）植物多樣性對(duì)模擬氮沉降的響應(yīng)格局因土地利用歷史不同而異,。該研究在國際上首次揭示了熱帶亞熱帶區(qū)域氮沉降與土地利用歷史變化對(duì)森林植物多樣性的影響具有“交互作用”。
該研究表明了土地利用歷史變化是決定森林植物多樣性對(duì)氮沉降響應(yīng)的重要因素,，研究結(jié)果對(duì)于評(píng)估當(dāng)前人類活動(dòng)和大氣氮沉降不斷加劇的背景下森林植物多樣性的變化具有重要的意義,。（生物谷Bioon.com）
生物谷推薦原文出處：
Environmental Pollution doi:10.1016/j.envpol.2010.10.037
Effects of experimental nitrogen additions on plant diversity in tropical forests of contrasting disturbance regimes in southern China
Xiankai Lua, Jiangming Moa, , , Frank S. Gilliamb, Guirui Yuc, Wei Zhanga, Yunting Fanga and Juan Huanga
a Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510160, China
b Department of Biological Sciences, Marshall University, Huntington, WV 25755-2510, USA
c Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
Abstract
Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (with harvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha?1 yr?1, and 100 kg N ha?1 yr?1. Nitrogen additions did not significantly affect understory plant richness, density, and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in this forest. In the rehabilitated forest, species richness and density showed no significant response to N additions; however, understory cover decreased significantly in the N-treated plots, largely a function of a significant increase in canopy closure. Our results suggest that responses of plant diversity to N deposition may vary with different land-use history, and rehabilitated forests may be more sensitive to N deposition.
Research highlights
? Nitrogen addition had no significant effect on understory plant diversity in the disturbed forest. ? Nitrogen addition significantly decreased understory plant cover. ? Nitrogen addition had no effect on richness and density in the rehabilitated forest. ? The decrease is largely a function of a significant increase in canopy closure. ? Land-use practices may dominate the responses of plant diversity to N addition.
Research in disturbed forests of southeastern China demonstrates that land-use history can substantially alter effects of excess nitrogen deposition on plant diversity of tropical forest ecosystems.
Keywords: Nitrogen deposition; Biodiversity; Tropical reforestation; Land-use history; Light limitation
