Both perceived green and blue space were significantly associated with lower levels of depression, with perceived biodiversity fully mediating the relationship between perceived green space quantity and depression and partially mediating the effect of perceived blue space quality.
Key Findings
Results
Perceived green space was significantly associated with lower levels of depression.
Data were obtained from the 2021 Chinese General Social Survey (CGSS), a cross-sectional study.
Ordered logistic regression was used to analyze the associations of perceived green and blue space with depression.
Both perceived green space quantity and quality showed significant associations with depression outcomes.
Green space quality and quantity exerted effects through different pathways (direct vs. mediated).
Results
Perceived blue space was significantly associated with lower levels of depression.
Both perceived blue space quantity and quality were significantly associated with lower levels of depression.
Perceived blue space quality and quantity operated through different mechanisms — quality through partial mediation by perceived biodiversity, quantity through direct pathways.
Analysis was conducted using ordered logistic regression on CGSS 2021 data.
Results
Perceived biodiversity fully mediated the relationship between perceived green space quantity and depression.
Mediation analysis was conducted to test whether perceived biodiversity exerted indirect effects on depression.
Perceived biodiversity acted as a full mediator between perceived green space quantity and depression, meaning the effect was entirely indirect.
This positions perceived biodiversity as a cultural ecosystem service linking nature exposure to mental health outcomes.
Results
Perceived biodiversity partially mediated the relationship between perceived blue space quality and depression.
In contrast to the full mediation observed for green space quantity, perceived biodiversity only partially mediated the effect of perceived blue space quality on depression.
This indicates that perceived blue space quality had both direct effects on depression and indirect effects operating through perceived biodiversity.
Mediation analysis was used to test these indirect pathways.
Results
Perceived green space quality and perceived blue space quantity exerted their effects on depression primarily through direct pathways.
Unlike green space quantity and blue space quality, perceived green space quality and perceived blue space quantity did not rely primarily on perceived biodiversity as a mediator.
These dimensions operated largely through direct associations with depression rather than indirect pathways.
This finding highlights differential mechanisms through which various dimensions of green and blue space influence mental health.
Discussion
The study integrated subjective perceptions of green and blue space with perceived biodiversity as a cultural ecosystem service to examine mechanisms linking nature and mental health.
The study used data from the 2021 Chinese General Social Survey (CGSS), situated in the context of rapid urbanization in China.
Cultural ecosystem services framework was employed to conceptualize perceived biodiversity as a mediating mechanism.
Cross-sectional study design was used, limiting causal inference.
The findings suggest urban planning should prioritize 'high-quality and biodiverse green and blue infrastructure as part of broader strategies to enhance mental health in rapidly urbanizing societies.'
Guo Z, Lu C, Fan L, Chen Y. (2026). Perceived green and blue space, perceived biodiversity, and depression: Empirical evidence from China based on cultural ecosystem services.. Public health. https://doi.org/10.1016/j.puhe.2026.106215