有机肥和植被去除管理对人工林土壤节肢动物多样性的影响

Abstract

施用有机肥和林下抚育（植被去除）是人工林重要的管理措施；土壤节肢动物物种丰富，是土壤生态系统的重要组成成分，对环境变化敏感，可以作为森林管理的指示生物。人工林植被去除和施肥管理影响土壤性质、资源输入量及微生物多样性，从而影响土壤节肢动物多样性，但是相关研究还十分缺乏。以沿海地区杨树人工林为对象，研究了施用有机肥和林下植被去除对土壤节肢动物的数量和多样性的影响。结果表明，有机肥和植被去除管理对不同土壤层土壤节肢动物的数量和多样性指标影响不一致。有机肥增加0-10 cm深度土壤节肢动物总数量、蜱螨目数量，降低土壤节肢动物群落物种丰富度、均匀度和Shannon多样性指数；植被去除减少0-10 cm深度土壤节肢动物总数量和弹尾目数量，降低均匀度指数。两种处理对10-20 cm深度土壤节肢动物群落的数量和各多样性指标影响不显著。总体来说（0-20 cm），有机肥处理土壤节肢动物的数量显著增加，优势类群前气门亚目（Prostigmata）的数量增长为对照的4倍，但是土壤节肢动物群落的均匀度和Shannon多样性指数显著降低，这可能是土壤节肢动物优势类群前气门亚目密度急剧增加，而物种丰富度没有变化所导致；此外，施用有机肥增加了土壤有机质、总氮、有效磷的含量，降低土壤pH值，并且与前气门亚目密度显著相关。林下植被去除没有影响0-20 cm深度土壤节肢动物的数量和各多样性指标。;Plantations provide important wood resources and also play an important role in mitigating climate change. Establishing poplar plantations is a common practice for improving the quality of reclaimed coastal saline soils in Eastern China. Organic fertilizer application and understory plant removal are two common management practices to promote plantation growth. Soil arthropod is a critical component in the ecosystem processes of organic matter decomposition and nutrient cycling. The abundance and diversity of arthropods can reflect changes in soil quality and ecosystem functionality. Studies have demonstrated that the abundance and diversity of soil arthropods might be impacted by changes in the quality and quantity of forest understory plant materials, as well as soil chemical and physical properties. However, the extent to which intensive forest management practices to alter soil arthropod communities remains elusive. In this study, we examined the effects of applying organic fertilizers (OF) and removing understory plants (UP), on the abundance and diversity (i.e. richness, evenness, and Shannon's index) of soil arthropods of poplar plantations in a reclaimed coastal area of northern Jiangsu Province, China. We found that Acari and Collembola were the two of the most abundant soil arthropod groups. The OF application significantly increased the total abundance of soil arthropod and the abundance of Acari, significantly decreased diversity index while UP removal decreased the total abundance of soil arthropod, the abundance of Collembola, evenness in 0-10 cm soil. Both of the two practices had no impact on the total abundance and diversity index at 10-20 cm soil. As a whole 0-20 cm depth of the soil, the application of the OF significantly increased the total abundance of soil arthropods, while it decreased the evenness and Shannon's index. The abundance of Prostigmata mites increased almost four folds with the application of the OF treatment in contrast to the control. The increased abundance of dominant groups led to the decrease in the arthropod evenness and Shannon's index based on the Order level. In addition, it was also presumably a consequence of reduced soil pH and improved soil properties (e.g., OM, TN, AP) with the application of the OF in this reclaimed coastal saline soil. The removal of understory plants did not significantly influence the abundance, richness, evenness and Shannon's index of soil arthropods in 0-20 cm depth of soil. Our results suggested that the organic fertilizers application is a preferable management practice to understory plant removal in order to elevate the abundance of soil arthropods while promoting poplar plantation productivity.