海南文昌滨海台地不同森林林下灌草多样性及其与土壤因子关联分析

采用典型抽样法，选取海南岛滨海台地3种典型热带森林类型（椰子林、人促更新次生林、次生林），对林下物种多样性及其土壤理化性质进行调查研究，并探讨物种多样性与土壤因子的相关性。 结果表明：灌木层中东风桔(Atalantia buxifolia)、 琼崖海棠(Calophyllum inophyllum)是3种森林类型的共有物种，其中在椰子林和人促更新次生林林型下占有较大优势；草本层中牛膝(Achyranthes bidentata)和地桃花(Urena lobata)是3种森林类型共有草本植物，但并非是优势种。次生林和人促更新次生林林下灌木层的多样性指数与均匀度指数都较高，林下物种组成相对复杂，共有树种有11种，相似系数高达45％。次生林林下植物多样性与土壤全氮、全磷、有效磷、速效钾及铵态氮之间达极显著正相关关系；人促更新次生林植物多样性与土壤全钾、全氮、速效钾、无机氮及铵态氮之间达极显著正相关；椰子林林下植物多样性与土壤各养分含量之间的相关性不明显。经多元逐步回归分析证实：滨海台地热带林土壤pH、全磷、全钾、速效钾、有效磷、铵态氮及无机氮共7个土壤因子对林下植物多样性具有显著影响。

Associated Analysis Between Forest Understory Vegetation Diversity and Soil Factors in Hainan Wenchang Coastal Platform

Understory plant species diversity and physicochemical properties of soil were researched at three types of typical tropical forest(Coconut Grove, secondary forest, Artificial regeneration forest)in the coastal terrace of the Hainan Island by typical sampling method, also discussed the correlation of the species diversity with the soil factors. The results showed that Atalantia buxifolia and Calophyllum inophyllum wre the common species of the three forest types in the shrub layer, in which had a large advantage in coconut forest and artificial regeneration forest; Achyranthes bidentata and Urena lobata were the common species of the three forest types in Herbage layer, but were not the dominant species. The diversity index and evenness index were higher, plant species composition was relatively complex and the total number of common species was 11 and the similar coefficient was as high as 45% of the secondary forest and artificial regeneration forest in the shrub layer. The plant species diversity had significantly positively correlated between soil total N, total P, available P, available K and ammonium nitrogen in the secondary forest, and had a significantly positively correlated between soil total K, total N, available K, nitrate nitrogen and ammonium nitrogen in the artificial regeneration forest, but had not obvious correlation in the coconut forest. Stepwise multiple regression analysis showed that the soil pH, total phosphorus, total potassium, effective phosphorus and potassium, ammonium nitrogen and inorganic nitrogen of seven soil factor had significant influence to the understory plant diversity in the Coastal terrace of the Hainan Island.