洞庭湖滩地杨树造林与草本植物物种多样性研究

Study on the afforestation of Poplus and the species diversity of herb in beach of Dongting Lake

对同一滩地杨树人工林草本植物层的物种组成和多样性进行了8年动态监测。随林龄增加,草本层的物种丰富度降低、个体总数增加;部分喜光性物种为更加耐荫的植物种类所更替,其β多样性增加;原有物种和优势种的保持率分别为56.3%和66.7%,草本层组成保持相对稳定。与造林前期比较,主伐阶段林下草本层α多样性变化不大;相似立地条件的林地与非林地草本层物种丰富度和组成有所不同,但α多样性仍非常接近。随滩地高程增加、淹水时间减少,草本植物层的物种丰富度和个体数增加,优势种优势度下降,α多样性增加。受淹水时间因素的制约,草本植物层的主要优势种群在湖区滩地常沿等高线呈环带状分布。

The species construction and diversity of the herb layer of Poplus artificial forest in same beach of lake were dynamic monitored in eight years. With the increase of the tree＇s age, the abundance of the species of the herb layer were decreased and the quantifies of the individual were increased, The lightloving plant species were instead by more shade tolerance species, and the β diversity was increased. The construction of the herb layer was stabilized, and the conservation rates of inhere species and superiority species was 56.3 % and 66.7 % separately. There was little obvious difference in a diversity of the herb layer which under the tree in cuttage period compared with the period before afforestation. There was obvious difference in the abundance and construction of the species of herb layer of forest land or non-forest land in similar site, and the u diversity in those areas were closely, With the increase of the altitude and the decrease of the flood time, the abundance and uruts of the herb layer were increased, the superiority rate of the superiority species were increased, and the α diversity were decreased. Due to the restriction of the different flood duration, the main superiority species groups of herb layer were districted as circularity with the altitude of beach of lake.