Impacts of restoration on the physico-chemical and microbiological properties of soil along restoration transects in a moorland ecosystem

In the UK, upland moorland soils of the Southern Pennines serves as a major terrestrial carbon sink with an estimated 16 to 20 million tonnes of carbon reserve. Historical land management practices coupled with the deposition of anthropogenic pollutants, fire and climate change have led to the severe degradation of this ecosystem leaving significant areas devoid of vegetation and characterised by unconsolidated bare peat. Severe peat erosion has expose the underlying mineral soil and led to the loss of stored carbon. Major restoration projects which involve liming and fertilization followed by nurse grass seeding have successfully revegetated areas of bare peat , but the effects on vegetation succession and particularly the below-ground ecosystems properties remain poorly understood. Thus, this research was aimed at preliminary understanding of the impacts of restoration on soil physico-chemical and microbiological properties in a moorland undergoing restoration at Holme Moss in the Southern Pennines. Soils were sampled (line transects) in vegetation mosaics representing the various stages of moorland plant community re-establishment. Integrated soil microbiological and physico-chemical analyses (pH, SOM, N, P, K and heavy metals) generated information on vegetation-dependent relationships. The study site was highly acidic (pH 3.7- 4.1), low in K+ and high in concentrations of N, P, Zn and Pb (in the vegetated sites). Statistically significant difference (p ≤ 0.05) between culturable soil microbial population in the restored and non-restored sites were identified, but a highly significant correlation observed between the microbial species and some heavy metals suggests that the microbial species in the site are tolerant to metal toxicity. The study concluded that vegetative conditions and restoration treatments clearly affected the physico-chemical and microbiological properties of soils which consequently influenced the rates of nutrients cycling and mobility of metals.

英国南奔宁山脉的高地沼地土壤是重要的陆地碳汇，其碳储量预估为1600万至2000万吨。历史土地管理实践叠加人为污染物沉降、野火与气候变化，导致该生态系统严重退化，大片区域植被消失，地表呈现松散裸露泥炭的特征。严重的泥炭侵蚀暴露了下层矿质土壤，并造成储存碳的流失。采用石灰改良、施肥后播撒保育草种的主流修复项目已成功让裸露泥炭区域恢复植被，但这类修复对植被演替，尤其是地下生态系统特性的影响仍不甚明晰。为此，本研究旨在初步探究南奔宁山脉霍尔莫斯沼地的修复工程对土壤理化及微生物特性的影响。研究人员在代表沼地植物群落重建不同阶段的植被镶嵌区域中，采用样线法采集土壤样品。通过整合土壤微生物与理化分析（pH、土壤有机质（SOM）、氮、磷、钾及重金属），获取了植被依赖性关系相关数据。研究样地呈强酸性（pH 3.7~4.1），钾离子（K+）含量较低，而植被覆盖区域的氮、磷、锌（Zn）与铅（Pb）浓度较高。研究发现修复与未修复样地的可培养土壤微生物种群数量存在显著统计学差异（p ≤ 0.05）；而微生物物种与部分重金属间存在极强相关性，表明样地内的微生物物种具备金属毒性耐受性。本研究结论指出，植被状况与修复措施显著影响了土壤理化及微生物特性，进而对养分循环速率与金属迁移能力产生作用。