Characteristics of Soil Macrofauna and Its Coupling Relationship with Environmental Factors in the Loess Area of Northern Shaanxi

Yongwei Zhou,Rui Gao,Ning Ai,Changhai Liu,Caixia Yuan,Xianghui Tuo,Jiafeng Qin,Zhiyong Zhang

doi:10.3390/su14052484

Abstract

Even with the in-depth implementation of forestry ecological projects, such as restoring farmland to forest (grass) in the loess area of northern Shaanxi, the characteristics of soil macrofauna communities and their coupling relationship with environmental factors after vegetation restoration in the study area are yet obscure. However, the soil macrofauna community characteristics are of great significance for evaluating the effectiveness of vegetation restoration in the study area. Therefore, the study aims to reveal the characteristics of the soil macrofauna community and their coupling relationships with the environment in the loess area of northern Shaanxi. In this study, all organisms of the five typical vegetation types in the study area were collected by manual sorting (Armeniaca sibirica and Populus simonii mixed forest (M), Robinia pseudoacacia (P), Populus simonii (S), Populus hopeiensis (H) and Hippophae rhamnoides (R)), and the adjacent abandoned grassland (G) was used as a control group. The group number and the individual number of soil macrofauna of different vegetation types in the study area and their coupling relationships with environmental factors are studied, and the following conclusions were drawn. (1) The study shows that there are certain differences in the environmental factors of different vegetation types in the study area, which include the significant differences in the alkaline nitrogen content of various vegetation types (p < 0.05). (2) The effects of different vegetation on soil macrofauna community were different. There were no significant differences in the soil macrofauna community structure between Armeniaca sibirica and Populus simonii mixed forest, Robinia pseudoacacia, Populus simonii and Populus hopeiensis, but there was a large difference from that of the abandoned grasslands. The community density of soil macrofauna in Armeniaca sibirica and Populus simonii mixed forest and Populus simonii were significantly higher than that in the abandoned grassland (p < 0.05), but the other indexes showed no significant differences. The Shannon–Wiener index of Robinia pseudoacacia and Populus hopeiensis were much lower than that of the abandoned grassland (p < 0.05). (3) The diversity of soil macrofauna communities was mainly affected by pH, alkaline nitrogen, potassium available, vegetation coverage and litter production. (4) Different groups of soil macrofauna were closely related and reacted differently to environmental factors, and vegetation coverage, litter production and alkaline nitrogen content were the key factors affecting the composition of soil macrofauna communities.

Highlights

With social and economic development, the soil surface environment of the loess area in northern Shaanxi has witnessed big changes under the impact of climate change and human activities
There are significant differences in the alkaline nitrogen content of all vegetation types (p < 0.05), but there is no significant difference among non-capillary porosity
This study found that the community structure of Armeniaca sibirica and Populus simonii mixed forest, Populus simonii, Robinia pseudoacacia and Populus hopeiensis were significantly different from that of the abandoned grassland (Figure 2)

Summary

Introduction

With social and economic development, the soil surface environment of the loess area in northern Shaanxi has witnessed big changes under the impact of climate change and human activities. Environmental problems, such as of soil erosion, biodiversity loss, land degradation, and ecosystem destruction, are becoming more and more severe [1], Sustainability 2022, 14, 2484. In order to make sure that national ecological security is sustained and to achieve a sustainable development, the Chinese government implemented forestry ecological projects, such as restoring farmland to forest (grass) in 1999, which has helped to improve the ecosystem and the service functions in the study area [3]. The studies on soil faunas at home and abroad have mainly focused on the following aspects: the decomposition process of soil fauna litter and its role in community succession [8,9], the role of soil faunas in ecological restoration [10], the reaction of soil fauna to land use patterns [11]

Methods

Results

Discussion

Conclusion