Research Highlight

Urban greenspaces are sources of pathogens, greenhouse gases

doi:10.1038/nindia.2021.100 Published online 20 July 2021

A global survey has revealed that urban greenspaces, located mostly in public parks and residential gardens, harbour higher proportions of microorganisms tied to human diseases, greenhouse gas emission processes and nutrient cycling than the neighbouring natural environments1.

The survey also indicated that urban greenspaces in warmer cities supported a higher proportion of fungal parasites and plant pathogens that are often economically important pests.

The findings of the survey showed that irrigated and mowed greenspaces could potentially be important sources of greenhouse gases (methane and nitrous oxide) to the atmosphere.

To date, the make-up of soil microorganism communities in urban greenspaces had not been thoroughly examined. To address this gap, an international research team, including a scientist, from the Banaras Hindu University in Uttar Pradesh, India, carried out a field survey across 112 sites from 17 countries in six continents.

Comparing urban greenspaces with nearby natural sites, they found that urban greenspaces harboured communities of soil bacteria and other microorganisms that were, on average, more diverse than the adjacent natural ecosystems, with no significant differences in the richness of fungi.

Analysing genes of soil microorganisms in urban greenspaces, the researchers identified genes associated with pathogenesis, antibiotic resistance, greenhouse gas emissions, nutrient cycling and abiotic stress, with higher proportions related to plant and human pathogens. 

The researchers say that city affluence, park management practices and climate contributed to the diversity of soil microbial communities in urban greenspaces, setting them apart from natural ecosystems.


References

1. Delgado-Baquerizo, M. et al. Global homogenization of the structure and function in the soil microbiome of urban greenspaces. Sci. Adv. 7, eabg5809 (2021)