8月8日,，從中科院西雙版納熱帶植物園獲悉，該園的博士研究生Gbadamassi G. O. Dossa等沿不同海拔高度對印度尼西亞龍目島的林加尼火山進行植物樣品的采集發(fā)現(xiàn),，海拔是決定群落組成的重要影響因素,。該研究成果在國際知名雜志《公共科學圖書館·綜合》上發(fā)表。
熱帶火山是一個還有待研究的重要生態(tài)系統(tǒng),，由于土壤更加低齡和均勻,，植物物種多樣性、植物組成變化與海拔的關系都與其他隆起山脈不同。
“我們采用小區(qū)和小區(qū)之間多樣性模型和協(xié)變量方法對林加尼火山的植物組成變化,、生物量,、海拔進行分析，同時,，根據(jù)海拔梯度對植物譜系結(jié)構(gòu)進行了調(diào)查,。”Gbadamassi G. O. Dossa告訴記者，他們共調(diào)查了92個物種的樹木和902棵灌木以及67個物種的地被植物,。發(fā)現(xiàn)隨著海拔高度的增加,，林下層、中層和冠層植物的小區(qū)多樣性呈下降趨勢,，而地被植物則呈現(xiàn)駝峰型模式,。
研究人員認為海拔是決定所有植物組成小區(qū)多樣性的最重要因素。地被植物的小區(qū)多樣性與葉面積指數(shù)呈負相關,，這說明低海拔地區(qū)的林下層植物多樣性受低光條件限制,。地被植物的小區(qū)之間多樣性隨海拔高度的增加而增加，而其他植物的物種組成則相反,。
“地表以上生物量與海拔高度沒有顯著的模型相關,，與小區(qū)多樣性模型也沒有顯著相關。低海拔地區(qū)的群落呈隨機譜系結(jié)構(gòu),，但海拔1600米以上的群落屬于聚集譜系結(jié)構(gòu),。”Gbadamassi G. O. Dossa解釋說。 研究表明,，在高海拔地區(qū)存在較強的環(huán)境篩選作用,，從而為植物物種多樣性隨海拔增加而減少提供了合理解釋。（生物谷 Bioon.com）
生物谷推薦的英文摘要
PLoS ONE doi:10.1371/journal.pone.0067720
Factors Determining Forest Diversity and Biomass on a Tropical Volcano, Mt. Rinjani, Lombok, Indonesia
Gbadamassi G. O. Dossa, Ekananda Paudel, Junichi Fujinuma, Haiying Yu, Wanlop Chutipong, Yuan Zhang, Sherryl Paz, Rhett D. Harrison
Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversity (Fisher's alpha), compositional change, and biomass against elevation and selected covariates. We also examined community phylogenetic structure across the elevational gradient. We recorded 902 trees and shrubs among 92 species, and 67 species of ground-cover plants. For understorey, subcanopy and canopy plants, an increase in elevation was associated with a decline in alpha-diversity, whereas data for ground-cover plants suggested a hump-shaped pattern. Elevation was consistently the most important factor in determining alpha-diversity for all components. The alpha-diversity of ground-cover vegetation was also negatively correlated with leaf area index, which suggests low light conditions in the understorey may limit diversity at lower elevations. Beta-diversity increased with elevation for ground-cover plants and declined at higher elevations for other components of the vegetation. However, statistical power was low and we could not resolve the relative importance to beta-diversity of different factors. Multivariate GLMs of variation in community composition among plots explained 67.05%, 27.63%, 18.24%, and 19.80% of the variation (deviance) for ground-cover, understorey, subcanopy and canopy plants, respectively, and demonstrated that elevation was a consistently important factor in determining community composition. Above-ground biomass showed no significant pattern with elevation and was also not significantly associated with alpha-diversity. At lower elevations communities had a random phylogenetic structure, but from 1600 m communities were phylogenetically clustered. This suggests a greater role of environmental filtering at higher elevations, and thus provides a possible explanation for the observed decline in diversity with elevation.
