不同林地清理和培肥措施对桉树人工林植物多样性的影响

【目的】探讨不同林地清理方式下不同培肥措施对植物多样性的作用规律,为桉树人工林的可持续经营提供理论依据。【方法】基于两种不同林地清理(火烧清理和人工清理)和3种不同培肥措施(加炭C、加氮N和套种绿肥)处理试验,比较研究不同林地清理和培肥措施的独立和交互作用对桉树人工林下植物多样性的影响。【结果】火烧清理和人工清理4年后,火烧清理林地的物种丰富度显著低于人工清理林地(P0.001);两种清理方式下加C、加N和套种绿肥均明显改变植物群落的组成和结构,但优势种保持不变,均为蔓生莠竹、弓果黍、小花露籽草和五节芒(套种绿肥中的小花露籽草除外),显著降低植物多样性指数(包括Shannon-Wiener指数、Simpson指数和Pielou均匀度指数);两种清理方式各处理林下植物功能群谱完全相同,均表现为禾草植物木本植物蕨类植物藤本植物杂草植物入侵植物;两因素方差分析表明,火烧清理和人工清理条件下,加C、加N、套种绿肥处理均极显著影响林下植物多样性指数,林地清理方式与不同处理的交互作用也对林下植物多样性指数产生极显著的影响。【结论】火烧和人工清理林地及加C、加N、套种绿肥等培肥措施对林下植物多样性存在显著影响。从维护生物多样性的视角出发,在桉树人工林的经营中应尽量减少加C、加N和套种绿肥等培肥措施的应用。

Effects of Different Ground Clearance and Fertilizing Treatments on Plant Diversity of Eucalyptus Plantations in Subtropical China

[Objective] To explore the effects of different fertilization measures on plant diversity under different ground clearance methods, and to provide theoretical basis for sustainable management of Eucalyptus plantations.[Methods] Based on two different ground clearance methods (fire and manual ground clearance) and three different fertilization measures (C addition, N addition and green manure plant interplantation), tests were conducted to compare and study the independent and interactive effects of different fertilization measures on plant diversity of Eucalyptus plantations.[Results] After 4 years of fire and manual ground clearance, the species richness in plantations with fire ground clearance method was significantly lower than that in plantations with manual ground clearance method (P < 0.001).C addition, N addition and manure plant interplantation significantly changed the composition and structure of the plant community under two types of ground clearance methods and significantly reduced the plant diversity index (including the Shannon-Wiener index, Simpson index and Pielou''s evenness index).While the dominant plants remained unchanged, all of them were Microstegium vagans, Cyrtococcum patens, Ottochloa nodosa and Miscanthus floridulus, except for Ottochloa nodosa in manure plant interplantation treatments.The plant functional groups spectrum in different ground clearance and treatments were identical with the trend of graminoids > woody > ferns > vines > herbaceous > invasive functional groups.The result of two-way ANOVAs revealed that treatments and the interaction between ground clearance and different treatments significantly influenced understory diversity index.[Conclusion] Fire ground clearance, manual ground clearance, C addition, N addition and manure plant interplantation had significant influence on understory diversity index.In order to maintain biodiversity, the application of fertilization measures such as adding C, adding N, and interplanting green manure should be minimized in the management of Eucalyptus plantations.