西南喀斯特高原盆地石漠化环境植物群落结构与物种多样性时空动态

为阐明西南典型喀斯特石漠化类型——喀斯特高原盆地石漠化植物群落结构和物种多样性特征及其演变规律,科学支撑喀斯特石漠化治理,选取了喀斯特高原盆地典型石漠化区贵州清镇簸箩小流域为研究区域,对其植被进行广泛的野外勘察,设置典型样方研究其植物群落结构和物种多样性特征;运用空间替代时间方法,研究石漠化演变过程中植物群落结构和物种多样性变化;基于2013—2015连续3 a的监测数据,研究其年际变化。结果表明:研究区群落结构简单,共记录到的植物分布58种,其中草本层18科24属28种、木本层17科25属30种;单种属的比例很高,为82.86%。不同等级石漠化环境植物群落高度、平均地径、平均冠幅、草本层生物量和灌木层生物量均具有显著差异;植物种群密度在不同等级石漠化环境变化依次为轻度石漠化中度石漠化潜在石漠化无石漠化。不同等级石漠化环境植物多样性指数、均匀度指数、丰富度指数和优势度指数均偏低,而且4种指数均与石漠化等级演替无明显耦合关系。不同年份植物群落高度、平均地径、种群密度和灌木层生物量随着时间的推移均呈增加趋势,但相邻年份增加不显著。研究区生态系统人为干扰逐渐减弱,植被呈现出正向演替的趋势,优势种的重要性趋于降低。该研究结果对我国西南喀斯特盆地生态功能恢复和石漠化植被重建具有一定的理论意义和实践指导价值。

Temporal-spatial dynamics for plant community structure and species diversity of rocky desertification ecosystem in karst plateau basin, southwest China

Karst rocky desertification has become a very serious eco-environment issue in southwest China, severely hindering the local sustainable development of economy and society. Vegetation restoration is key to the rehabilitation of karst rocky desertification and a series of comprehensive controls for rocky desertification have been carried out in karst areas. But there are very short of the studies on plant community structure and species diversity of karst plateau basin ecosystem in southwest China. And the responses of plant community structure and species diversity to the succession of rocky desertification are still unclear. All these seriously hinder the control of rocky desertification. In the present study, a typical rocky desertification ecosystem of karst plateau basin, Boluo small watershed in Qingzhen City of Guizhou Province, was selected as experiment site. And five sample plots were set up for each degree of karst rocky desertification, namely, nil, potential, slight, and moderate. Then, the plant community structure and species diversity were investigated by ecological survey method from 2013 to 2015. The results showed that the plant community structure of rocky desertification ecosystem was very simple, only 58 plant species including 28 herbaceous species(belonging to 18 families, 24 genera)and 30 shrub species(belonging to 17 families, 25 genera)were recorded, and 82.36% of them belong to monotypic genus. There are obvious differences of plant community structure between different degrees of rocky desertification, and the plant population density among different degrees of rocky desertification also varies obviously, with the order of slight > moderate > potential > nil. The indices of plant diversity, evenness, richness and dominance all are low, and each of them has no coupling relationship with the rocky desertification. Along with the increase of the years, the plant community height, ground diameter, population density, and shrub biomass show an increasing trend, but there are not significant differences between adjacent years. The human disturbances on the ecosystem in study area getting weaker, the importance of dominant species tends to decrease, and the vegetation shows a trend of positive succession. The results have important values for the restoration of rocky desertification in karst plateau basin, southwest China.