JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2022, Vol. 46 ›› Issue (4): 144-152.doi: 10.12302/j.issn.1000-2006.202103014

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Spatial variability and influencing factors of plant diversity in the shrub layers of artificial forests in China

GUO Hongting1(), JI Xiaofang2, WANG Cheng3, ZOU Hanlu3, WANG Liyan4, JIANG Jiang1,*()   

  1. 1. Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
    2. Institute of Agricultural Resource and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    3. Yongfeng County Guanshan Forest Farm, Ji’an 331500, China
    4. Jiangxi Academy of Forestry, Nanchang 330032, China
  • Received:2021-03-05 Revised:2021-07-12 Online:2022-07-30 Published:2022-08-01
  • Contact: JIANG Jiang E-mail:1065339150@qq.com;ecologyjiang@gmail.com

Abstract:

【Objective】 The shrub layer is an important part of the forest ecosystem and plays a key role in maintaining the structure of the forest community and protecting biodiversity. The spatial variability and influencing factors of plant diversity in the undergrowth shrub layers of artificial forests in China were analyzed, providing a reference for regulation of plant diversity under plantations. 【Method】 In this paper, by establishing a database of plant diversity in undergrowth shrubs of artificial forests in China, structural equation modeling (SEM) was used to reveal the spatial variability and influencing factors of plant diversity in undergrowth shrubs in artificial forests. 【Result】 (1) Plant diversity in the forest shrub layer gradually decreased from south to north. (2) As the tree diameter at breast height increased, the plant diversity of the shrub layer gradually increased. However, the distribution uniformity tended to decrease. (3) As the canopy closure of the artificial forests increases, the plant diversity initially increased and then decreased. When the Shannon-Wiener diversity index reached its peak, the canopy closure was approximately 65.8%. (4) As the forest density increased, the plant diversity of the shrub layer gradually decreased. (5) Temperature, precipitation, canopy closure, diameter at breast height, tree height and stand density all had direct or indirect effects on the plant diversity of the understory shrub layer. The canopy closure had a threshold of 65.8%, and when it exceeded this threshold, temperature and precipitation were the dominant influencing factors. When the canopy closure was lower than this threshold, the weight of the influence of temperature decreased. The leading role of understory light was enhanced. 【Conclusion】 To explore the spatial variations and influencing factors of plant diversity in the understory shrub layer of artificial forests, it is necessary to consider various influencing factors, and evaluate the change in understory plant diversity with the help of the diversity index. The results of this study can provide a reference basis for regulating plant diversity in the understory shrub layer and the restoration of understory plants.

Key words: artificial forest, undergrowth shrub layer, biodiversity, structural equation model (SEM)

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