贵州喀斯特石漠化地区植物多样性与土壤理化性质

以贵州典型喀斯特石漠化生态系统环境为研究对象,运用野外取样调查和实验室检测分析方法,研究不同等级石漠化环境植物多样性和土壤理化性质特征及其相关性;运用空间替代时间方法,探讨石漠化演替过程中植物多样性和土壤理化性质的响应,旨在为贵州乃至整个中国西南喀斯特森林生态保护和石漠化生态系统恢复重建提供理论支撑。结果表明:1)石漠化环境植物群路组成简单,物种丰富度也很低,且随着石漠化程度增加,植被物种组成呈递减趋势;不同等级石漠化环境植物多样性具有显著差异,均匀度指数变化与石漠化等级演替明显耦合,显示了随石漠化程度增加而减小的变化趋势。2)不同等级石漠化环境土壤理化性质存在显著差异,随着石漠化程度增加,土壤理化性质显示了先退化后改善的响应过程。土壤有机质、氮素、毛管持水量、容重和孔隙度与植物多样性具有明显的相关性,在改善土壤理化性质和促进植物多样性恢复方面起着关键作用。3)主成分分析表明,土壤有机质、氮素、钾素、持水状况、孔隙度和植物多样性均匀度指数等是基于土壤理化性质和植物多样性评价石漠化程度的关键指标。基于上述结果,进一步阐述了石漠化演替过程中植物多样性和土壤理化性质的变化规律和响应机制。研究结果对我国西南喀斯特森林生态保护和石漠化生态系统恢复重建具有一定的理论意义和实践指导价值。

Plant diversity and soil physical-chemical properties in karst rocky desertification ecosystem of Guizhou, China

Karst rocky desertification has been an important ecological issue hindering the economy and society development of South China Karst region, and the control of rocky desertification has been clearly listed in the national projects of economy and society development.. But there are highly short of plant diversity and soil science researches in karst rocky desertification ecosystem, and the successions of plant diversity and soil physical-chemical properties are still unclear in the process of rocky desertification, all which hardly hinders the control of rocky desertification well work.Based on these problems, in this study, firstly, three typical rocky desertification regions, that is, Yachi, Hongfenghu, and Huajiang of Guizhou Province, representing three different typical karst landforms of plateau mountain, plateau basin, and plateau gorge, respectively, were selected as experiment areas, and 45 sample plots with area of 20 m × 20 m, respectively, were set up for the 5 typical degrees of rocky desertification surrounding, that is, nil, potential, low, middle, and high, in these three experiment areas. Then, the plant diversity and soil physical-chemical properties were surveyed and analyzed by methods of ecological survey, chemical determination, and mathematical statistics. Results show that 1) the vegetation is very simple with extreme low richness in rocky desertification surroundings, and with the increased degree of rocky desertification, the plant diversity appear remarkable change, for example, species is more few, importance value of dominant species is more high, and structure of plant community and ecological niche is more confusion. 2) There are significance differences of soil physical-chemical properties between different degrees of rocky desertification, and there is remarkable correlation between soil physical-chemical properties and plant diversity in rocky desertification ecosystem. 3) Principal component analysis show that the evenness index of plant diversity together with its correlative soil physical-chemical factors can represent the degradation degree of karst ecosystem. Results have important values in the protection of karst forest ecosystem and the control of rocky desertification.