黄淮海平原矿区采煤沉陷湿地生境演化轨迹研究

    Study on the habitat evolution pathways of coal mining subsidence wetlands in the Huang-Huai-Hai Plain

    • 摘要: 黄淮海平原作为典型煤粮复合主产区,采煤沉陷积水形成湿地,然而新成湿地易面临农业废水威胁,生态系统敏感且不稳定。本文基于黄淮海平原现场踏勘采样和室内测试数据,以江苏省徐州市、山东省邹城市、安徽省淮北市和淮南市的6个采煤沉陷湿地和1个自然湿地为研究对象,解析湿地生境演变特征,探索采煤沉陷湿地演变规律与形成机理。研究结果表明,沉陷湿地的植物物种组成随生境同步演变,从最初的旱生杂草向湿生草本及湿生灌木发展,植物生物量呈现快速增长、稳定维持、缓慢分化的规律。水体特性亦是随恢复时长逐步向自然湿地演化。不同恢复时长湿地的水体理化性质存在显著性差异(P<0.05),其中,化学需氧量(COD)、溶解性总固体(TDS)和电导率(EC)均呈现初期较高、中期达峰、后期递减并稳定的演化特征。底泥理化性质、酶活性、微生物多样性及物种组成符合扰动-退化-恢复-趋近自然的演替逻辑。有机碳(SOC)、可溶性有机碳(DOC)、微生物碳(MBC)、颗粒有机碳(POC)四个有机碳组分含量在恢复初期有小幅波动,后续逐渐增加至稳定。不同恢复年限的采煤沉陷湿地底泥细菌和真菌α多样性存在显著差异(P<0.05),且呈现出随恢复时长先下降后增加最终趋稳的变化趋势。此外,不同恢复时长湿地微生物群落组成呈现显著分异,且细菌群落与真菌群落的响应规律存在明显差异。细菌群落中,恢复时长在30 a以下的湿地细菌优势菌门为绿湾菌门(Chloroflexota)、酸杆菌门(Acidobacteriota)、放线菌门(Actinomycetota)、厚壁菌门(Bacillota)和假单胞菌门(Pseudomonadota)。而子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、被孢霉门(Mortierellomycota)是不同恢复时长湿地的优势真菌菌门,但随着恢复时长增长呈现出子囊菌门(Ascomycota)逐渐增加、担子菌门(Basidiomycota)逐渐减少并趋于稳定的总体趋势。总体上,采煤沉陷湿地恢复30 a以上时,在植被群落层面、水体环境层面、土壤环境层面及微生物群落层面,均恢复到或无限趋同于原生湿地水平。

       

      Abstract: The Huang-Huai-Hui Plain is a typical coal-grain composite production area, where coal mining subsidence creates wetlands through water accumulation. However, these newly formed wetlands are susceptible to threats from agricultural wastewater, resulting in sensitive and unstable ecosystems. Based on field surveys, sampling, and laboratory testing data from the Huang-Huai-Hai Plain, this study selects six coal mining subsidence wetlands and one natural wetland in Xuzhou City (Jiangsu Province), Zoucheng City (Shandong Province), and Huaibei City and Huainan City (Anhui Province) as research subjects to analyze the evolution characteristics of wetland habitats and explore the evolutionary patterns and formation mechanisms of coal mining subsidence wetlands. The study finds that plant species composition in subsidence wetlands evolves synchronously with habitat conditions, progressing from initial xerophytic weeds to hygrophytic herbs and shrubs, with plant biomass following a pattern of rapid growth, stable maintenance, and gradual differentiation. Significant differences in water physicochemical properties are observed among wetlands with varying restoration durations (P<0.05), with chemical oxygen demand, total dissolved solids, and electrical conductivity all exhibiting an evolutionary pattern characterized by initially high values, mid-term peaking, and subsequent decline and stabilization. The physicochemical properties of wetland sediments, enzyme activities, microbial diversity, and species composition follow a succession logic of disturbance-degradation-restoration-convergence toward natural conditions. The contents of soil organic carbon, dissolved organic carbon, microbial biomass carbon, and particulate organic carbon show minor fluctuations during the early restoration stage, followed by a gradual increase to stability. Also, significant differences in bacterial and fungal α-diversity are detected in subsided wetland sediments under different restoration years (P<0.05), displaying a temporal trend of initial decline, subsequent increase, and ultimate stabilization with prolonged restoration duration. Furthermore, microbial community composition varies significantly across restoration durations, with distinct response patterns observed between bacterial and fungal communities. Within bacterial communities, Chloroflexota, Acidobacteriota, Actinomycetota, Bacillota, and Pseudomonadota dominate in wetlands with restoration durations of less than 30 years. Ascomycota, Basidiomycota, and Mortierellomycota are the dominant fungal phyla across different restoration durations. However, a general trend of increasing Ascomycota and decreasing Basidiomycota with prolonged restoration is observed, ultimately approaching stability. Overall, coal mining subsided wetlands restored for over 30 years achieve or asymptotically converge to native wetland levels in terms of vegetation communities, aquatic environments, soil environments, and microbial communities.

       

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