Work

Multi-Scale Variations in Understory Community Diversity and Their Driving Mechanisms Under Urbanization Pressure: A Case Study of Shanghai, China

Year: 2026

Type: article

Abstract: Understory community diversity in urban forests is crucial for maintaining urban ecosystem functions and enhancing urban resilience, but it is threatened by rapid urbanization. Currently, there remains a knowledge gap regarding the multi-scale responses and driving mechanisms of understory community diversity along urbanization gradients, which hinders its scientific conservation and management. This study was conducted in Shanghai, a highly urbanized metropolis in China, at both plot and site scales. A total of 75 plots and 380 quadrats were established across 16 urban forest sites. Five key environmental factors were selected, including distance from the city center, visitor intensity, non-native species richness, overstory coverage, and forest area. Using taxonomic and phylogenetic diversity, regression models and null models were employed to analyze the multi-scale patterns and underlying assembly processes of understory plant communities. The results showed that the effects of environmental factors were scale-dependent, with environmental filtering as the core assembly mechanism. At the plot scale, the distance from the city center exhibited a U-shaped relationship with species richness (p = 0.005), while visitor intensity displayed a unimodal pattern with both species richness (p < 0.001) and Faith’s phylogenetic diversity (PD, p = 0.029). Increased non-native species richness intensified phylogenetic clustering (p < 0.05), and environmental filtering was the dominant process of community assembly. At the site scale, the β-diversity of non-native species drove the increase in phylogenetic the β-diversity of understory communities (p < 0.001); geographical distance had a significant positive effect on βMNTD (p = 0.002); and differences in non-native species could weaken biotic homogenization (p < 0.05). This study clarifies the multi-scale response patterns and driving mechanisms of understory community diversity and structure, providing a scientific basis for optimizing the conservation and management of understory vegetation in urban forests and enhancing urban ecosystem stability. Future work calls for long-term monitoring and broader environmental indicators.

Source: Diversity

DOI: 10.3390/d18050265

Authors: Kang Xu, Yeqian Chen, Ruisen Lu, Guiwu Zou, Zhi Peng, Shanshan Xu

Institutions: Wuxi University, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangxi Agricultural University, Shanghai Science and Technology Museum

Language: English

Topic: Ecology and Vegetation Dynamics Studies

Subfield: Nature and Landscape Conservation

Field: Environmental Science

Domain: Physical Sciences

SDGs: Sustainable cities and communities, Life on land

Open Access status: gold

Estimated APC paid: $2,534