Exploring biodiversity's impact on mental well-being through the social-ecological lens: Emphasizing the role of biodiversity characteristics and nature relatedness

The benefits of nature on mental well-being are extensively acknowledged, yet the role of biodiversity is often overlooked, with nature being treated as a homogeneous entity. Recognizing the complexity of perception and experiential processes, our study, grounded in a social-ecological framework, explores how various biodiversity characteristics shape its perception and subsequently contribute to mental well-being, uncovering pivotal environmental and individual factors. Spanning 21 varied green spaces in Chengdu, ranging from urban centers to nature conservation areas, our study encompassed a wide array of park areas, types, locations, and maintenance levels. We measured in-situ biodiversity, including the richness and abundance of bird, tree, shrub, and grass species, along with other green space characteristics such as tree cover, height, diameter, colorful foliage plant species, and native tree species. Data from 1124 green space visitors were collected on-site, encompassing perceived biodiversity, mental well-being, nature relatedness, and socio-demographic variables. Employing a multilevel regression model to account for the nested structure of individual and environmental data, our study reveals significant correlations between perceived biodiversity and species richness, as well as colorful foliage plants. Contrarily, tree abundance and cover, rather than species richness, emerged as a significant factor. Unexpectedly, native tree species exhibited a negative correlation with perceived biodiversity. Furthermore, we found mental well-being to be correlated only with perceived species richness, indicating that perceptions of species richness, rather than mere quantity, predominantly influence mental well-being. Additionally, nature relatedness was found to moderate the relationship between perceived biodiversity and mental well-being, underscoring the importance of individual characteristics in perceiving and experiencing biodiversity and deriving mental well-being. Our study contributes to understanding the complex interplay between biodiversity perception, individual nature relatedness, and mental well-being. These insights are vital for guiding environmental design and public health policies.