Edaphic fauna and soil properties under different managements in areas impacted by natural disaster in a mountainous region

ABSTRACT Soil invertebrate fauna plays a major role in several environmental processes, and its absence can negatively impact ecosystem health. This study aimed to assess the recovery of epigeal and edaphic invertebrate faunal communities following an environmental disaster, with landslides, mudflow, and river floods, in sites under different management systems, the effects of cover crops on invertebrate fauna, and their relationship with soil physical and chemical properties in the mountainous region of Rio de Janeiro State, Brazil. The following sites were evaluated: CF, a site under conventional farming without any record of natural hazard events; LS, a site impacted by an intense landslide event that left the area buried by mudflow; RO1, a site affected by river overflow and treated with NPK fertilizer and poultry litter; RO2, a site affected by river overflow and subjected to liming and heavy fertilization with NPK; and RO3, a site affected by a less intense river overflow and subjected to fertilization with poultry litter and NPK fertilizer. At each site, epigeal and edaphic fauna were sampled using pitfall traps and a monolith sampler, respectively. Physical (soil temperature, moisture, aggregate stability, and density) and chemical (pH in water, Ca2+, Mg2+, Al3+, K+, P, cation-exchange capacity, and total organic carbon) properties were determined in the 0.00-0.05 and 0.00-0.10 m layers. The predominant epigeal faunal groups were Entomobryomorpha, Poduromorpha, Diptera, and Coleoptera; and the predominant edaphic faunal groups, Coleoptera and Oligochaeta. There was a positive correlation between Coleoptera larvae, Hymenoptera, and species richness with total organic carbon. Coleoptera larvae were positively associated with biogenic aggregate stability, whereas Coleoptera was positively associated with physicogenic aggregate stability. Oligochaeta showed a positive correlation with soil moisture. Cover crops favored the development of epigeal and edaphic faunal groups that enhance soil properties through organic matter fragmentation and decomposition, and structural engineering. The strong correlation between soil chemical, physical, and biological properties demonstrate the importance of monitoring these components to assess the recovery of disaster-affected areas.

摘要
土壤无脊椎动物区系在诸多环境过程中发挥关键作用，其缺失会对生态系统健康产生负面影响。本研究旨在评估巴西里约热内卢州山区发生滑坡、泥石流及河流洪水等环境灾害后，不同管理体系样地的表栖与土栖无脊椎动物群落恢复情况，同时探究覆盖作物对无脊椎动物区系的影响，以及其与土壤理化性质的关联。
本次评估共设置5类样地：CF为采用常规耕作且无自然灾害记录的样地；LS为受强烈滑坡事件影响、区域被泥石流掩埋的样地；RO1为受河流泛滥影响，施用NPK肥料与家禽垫料的样地；RO2为受河流泛滥影响，施石灰并大量施用NPK肥料的样地；RO3为受轻度河流泛滥影响，施用家禽垫料与NPK肥料的样地。
在每处样地中，分别采用地面陷阱法（pitfall traps）与土柱采样器（monolith sampler）采集表栖与土栖动物样本。于0~5 cm及0~10 cm土层测定土壤物理性质（土壤温度、含水量、团聚体稳定性、容重）与化学性质（水提pH、Ca²+、Mg²+、Al³+、K+、磷、阳离子交换量、总有机碳）。
优势表栖动物类群为长角跳虫亚目(Entomobryomorpha)、短角跳虫亚目(Poduromorpha)、双翅目(Diptera)与鞘翅目(Coleoptera)；优势土栖动物类群为鞘翅目与寡毛纲(Oligochaeta)。
研究发现，鞘翅目幼虫、膜翅目(Hymenoptera)与物种丰富度均与总有机碳呈正相关；鞘翅目幼虫与生物成因团聚体稳定性呈正相关，而鞘翅目与物理成因团聚体稳定性呈正相关；寡毛纲与土壤含水量呈正相关。
覆盖作物可促进通过有机质破碎分解及土壤结构营建改善土壤性状的表栖与土栖动物类群的发育。土壤化学、物理与生物学性质间的强相关性，证实了监测这些组分对评估灾害受损区域恢复状况的重要性。