离子型稀土矿堆浸场地不同恢复年限植被多样性

生物群落多样性是判断生态系统稳定的重要指标,为了解人工建植对稀土矿废弃地生态系统的影响,以福建省长汀县离子型稀土矿堆浸废弃地为研究对象,利用植被恢复固定监测点,选取植被恢复5、8、11 a废弃地为样点,调查不同恢复年限样地物种种类和数量,分析稀土矿废弃地物种多样性随恢复时间的变化规律。结果表明:随植被恢复年限的增加,前期人工种植的植物逐渐被本土野生植物取代,增加物种以禾本科和菊科植物为主。乔木层、草本层植物种类和数量随恢复年限的增加而增加;随着植被恢复年限的增加,稀土矿废弃地乔木层物种丰富度(Gleason指数、Margalef指数)、Shannon指数逐渐增加,而乔木层、草本层Pielou均匀度指数则呈先增加后下降趋势;植被恢复8与11 a植被相似度最高,其次是植被恢复5与8 a,其中植被恢复11 a与对照样地植被相似度最低;Margalef指数、Simpson指数与Shannon指数呈显著相关。因此,随着植被恢复年限的增加,稀土矿生态退化区植被恢复前期人工干涉效应在逐渐降低,后期演变为自然演替,物种群落结构和种类发生变化,但与当地本土植物群落仍存在一定差异,表明生态退化区植被演替仍处于动态变化阶段。

Plant species diversity in different ecological recovery years of a heap leaching wasteland of a rare earth mining area

Biodiversity is an important indicator of ecosystem stability.To understand the impacts of artificial planting on rare earth mine wastelands,the Changting Fujian ionite rare earth mine heap leaching wasteland was examined.Fixed monitoring points were selected from within the abandoned land(5,8,and 11 a)as sampling points for vegetation restoration.We investigated the different species and numbers of plants across different recovery years and analyzed the changes in the species diversity of abandoned rare earth mine land with recovery time.The results showed that with the increasing vegetation restoration period,the artificially planted species were gradually replaced by native wild plants,of which the main species were mainly Gramineae and Asteraceae.The species and number of plants in the tree and herb layers increased with the increasing restoration period.With the increase in the vegetation restoration years,the species richness(Gleason and Margalef)and Shannon indices of the arbor layer in the abandoned land of rare earth mines gradually increased,while Pielou’s evenness index of the arbor and herb layers showed an increasing trend and then decreased.The vegetation restorations at 8 and 11 a were the most similar concerning vegetation,followed by 5 and 8 a.Regarding similarities in the vegetation,the vegetation restoration at 11 a was the least similar to the control plot.The Margalef and Simpson indices were significantly correlated with the Shannon index.In conclusion,with the increase in the vegetation restoration time,the artificial interference effect of vegetation restoration in the rare earth ecological degradation zone gradually decreased in the early stage,and evolved into natural succession in the later period,causing the species and community structure to change.However,there were still some differences relative to the local native plant community,indicating that vegetation succession in the ecologically degraded area was still in a dynamic stage.