Mental health is positively associated with biodiversity in Canadian cities

Abstract

Cities concentrate problems that affect human well-being and biodiversity. Exploring the link between mental health and biodiversity can inform more holistic public health and urban planning. Here we examined associations between bird and tree species diversity estimates from eBird community science datasets and national forest inventories with self-rated mental health metrics from the Canadian Community Health Survey. We linked data across 36 Canadian Metropolitan Areas from 2007-2022 at a postal code level. After controlling for covariates, we found that bird and tree species diversity were significantly positively related to good self-reported mental health. Living in a postal code with bird diversity one standard deviation higher than the mean increased reporting of good mental health by 6.64%. Postal codes with tree species richness one standard deviation more than the mean increased reporting of good mental health by 5.36%. Our results suggest that supporting healthy urban ecosystems may also benefit human well-being.

Keywords: Environmental sciences; Geography.

Fig. 1. Bird species diversity and tree species richness were significantly related to self-rated mental health.

Number represent parameter estimates of generalized additive models exploring the association between biodiversity variables and self-rated mental health from the Canadian Community Health Survey (CCHS). Grayed out values were not statistically significant (95% confidence intervals around parameter estimates overlapped with zero). In “biodiversity” models, only species diversity and greenspace and bluespace variables were included, “socio-dem” models added socio-demographic variables, and “health” models added health behavior and socio-demographic variables. All data were included, and data were stratified by neighborhoods with high socio-economic status (low marginalization) and low socio-economic status (high marginalization). Icons from the Noun Project.

Fig. 2. Higher bird species diversity and tree species richness was associated with better self-rated mental health.

The association between the probability of good self-rated mental health in the Canadian Community Health Survey and tree species richness (left panel) and bird Shannon diversity (right panel) predicted from generalized additive models. Shading represents standard error. In “biodiversity” models, only species diversity and greenspace and bluespace variables were included, “sociodem” models added socio-demographic variables, and “health” models added health behavior and socio-demographic variables. All data were included, and data were stratified by neighborhoods with high socio-economic status (low marginalization) and low socio-economic status (high marginalization). Icons from the Noun Project.

Fig. 3. Bird species diversity and tree species richness had a similar independent effect on self-rated mental health as the amount of fruit and vegetables consumed.

Odds ratio of each biodiversity and greenspace and bluespace, socio-demographic, and health behavior variable in a generalized additive model predicting good self-rated mental health of respondents in the Canadian Community Health Survey. Error bars represent standard error. The inset shows a closer view of biodiversity and greenspace and bluespace covariates. Icons from the Noun Project.