低丘人工林林下植被物种多样性初步研究

选取江西省泰和县狗丝茅岭低丘荒山人工造林l0a的人工生态系统中8种人工林主要类型和1个对照区，通过比较这些类型林下植被的物种多样性(物种丰富度和Shannon-Wiener指数)和相关的环境因子，揭示林下植被物种多样性的差异及其与环境因子之间的关系。结果显示：人工林类型(造林树种)、林分组成(纯林或混交林)和林分密度对物种多样性的影响较为明显，其中林分密度的影响最为显著：各人工林类型林下植被的Shannon—Wiener指数与物种丰富度具有大体相似的规律，即在相近造林密度下，不同造林树种其林下植被物种多样性以针叶纯林稍占优势，针阔混交林次之，而阔叶纯林相对较低：针叶林林下植被物种多样性虽然最高，但针叶林土壤的持水力相对较差，有机质含量也较低，而阔叶纯林相对较好，针阔混交林则最佳。

Species Diversity in Undergrowth of Artificial Forests on Lower Hilly Land

Artificial pure forests of Pinus rigida var. serotina, P. elliottii,Eucalyptus robusta,Schima superba, Liquidambar formosana,and mixed forests of L. formosana / P. massoniana or P. elliottii,which were planted in 1991 in seriously disturbed lower hilly land in Taihe county, Jiangxi Province, were investigated after 10 years. Changes of species diversity in the restored vegetation were measured. Before afforestation there were only 7 species such as Setaria viridis,Arundinella hirta,Rosa laevigata and Smilax china. In 1993 and 2001, the number of species increased to 21 and 58, respectively. In condition of the same density of plantation, the species diversity in the vegetation of the plantations was high in pure conifer forest, followed by conifer broadleaved mixed forest and broadleaved pure forest. The effects of afforestation species, stand structure (pure or mixed) and especially stand density on species diversity were obivious. However, conifer forest was poor in water holding, the soil under which had lower content of organic matters. Conifer broadleaved mixed forest is best for maintenance and restoration of species diversity and for improvement of soil and ecological environment.