南方稀土尾矿苔藓结皮过程及其生态效应

The ecological restoration of the rare earth tailings in South China has been an intractable problem in the restoration of mine environment, and it is important to explore new ways during ecological restoration. The moss crust can effectively fix and improve the soil, and promote the positive succession of vegetation. It was found that the moss crust was widely distributed in the rare earth tailings of south China, but the establishment and mechanism of the moss crust were still unclear, which restricted its application in the mine ecological restoration. This project takes the moss crust on rare earth tailing in south Jiangxi as the research object, employing field investigation and artificial cultivation, combined with the focus on: 1) the distribution characteristics of tailings moss crust, species composition and dominant species; 2) succession of moss crusts; 3) effect of moss crust in the ecological restoration of mining; 4) exploration of artificial breeding and artificial moss crust. Expounding the structure of the moss crust in rare earth tailings, and revealing its establishment and mechanism, can provide scientific basis for exploring new methods for the ecological restoration of the mine.

南方稀土尾矿生态修复一直是矿山环境恢复治理的难点，研究发掘新的生态恢复途径十分重要。苔藓结皮具有效固定和改良土壤，促进植被正向演替的功能。调查发现，苔藓结皮在南方稀土尾矿广泛存在，但其结皮过程和机理仍不清楚，制约了其在矿山生态恢复中的应用。本项目以赣南稀土尾矿苔藓结皮为研究对象，运用野外调查、人工培育相结合的方法，重点研究：1）尾矿苔藓结皮的分布特征、物种组成结构及优势种群；2）苔藓结皮的演替过程；3）苔藓结皮在矿山恢复中的生态效应；4）优势结皮苔藓的人工繁育及人工结皮的探索。阐明南方稀土尾矿苔藓结皮的结构，揭示其形成过程与机理，研究成果可为矿山生态修复实践探索新的途径提供科学依据。

一、项目背景.南方稀土尾矿的生态修复是亟待解决的重大问题。修复过程中水土留存和土壤改良又是解决问题的关键，生物土壤结皮（BSCs)可在这两个方面发挥重要作用。.二、研究内容、重要结果及关键数据.1. 结皮苔藓的分布特征、物种组成结构及优势种群.在原矿、果林、堆浸地、原位浸地和农田5种生境中，鉴定苔藓植物36科66属118种，优势苔藓植物为各生境共有种。土壤水含量和坡位直接影响稀土矿区苔藓植物多样性。土壤因素对苔藓植物分布的影响最大，其中，土壤水含量对苔藓植物分布的影响最重要。.2. 土壤结皮的演替过程.研究了裸土、藻结皮、藻-藓结皮、地衣结皮、地衣-藓结皮、苔藓结皮和草本维管植物7个阶段生物多样性及其相互关系。随着BSCs 的演替，微生物群落多样性和丰度显著提高；BSCs 演替增强了细菌、真菌和藻类群落物种间的相互作用。.3. 苔藓结皮的生态效应.BSCs 演替显著改善离子型稀土矿尾矿的土壤理化性质；BSCs显著提高了截流降水能力和持水能力；苔藓结皮显著提高萌发的物种数和萌发率；马唐在矿区植被修复中具有较好的应用前景。.4. 优势结皮苔藓的人工繁育及人工结皮的探索。.尿素0.3g/L时，小球藻生长最佳；不添加6-BA的培养基有利东亚小金发藓发育；藻—藓混合培养的正交试验显示pH和起始藻浓度对于东亚小金发藓生长有显著影响。.三、科学意义.1. 揭示南方稀土尾矿苔藓结皮过程关键环境因子。水分制约了矿区苔藓植物多样性及其分布，充足的水分供应是保障采后植被原生演替的关键。合理改造地形可提高修复效率。.2. 揭示苔藓结皮的物种组成及其相互作用机制。微生境影响裸土到藻结皮阶段的发育，环境胁迫和土壤资源竞争共同作用驱动了藻结皮以后的演替发生。细菌群落丰度对真菌和藻类群落丰度具有正影响，其中对真菌影响极显著；真菌群落丰度对藻类丰度有负影响。细菌群落在土壤结皮的演替过程中发挥着先导性和基础性的作用。