In the past few years, the development discourse in Nagpur has assumed ‘development vs environment’ debate, thanks to gaps in understanding of the intricate relationship between urban planning and greenspaces. Against this backdrop, an interesting study conducted at global level has recorded an important finding, “Urban greenspaces are important hotspots of local soil microbial taxonomic and functional diversity and also support a global homogenization in the structure and function of the soil microbiome.” The study titled ‘Global homogenization of the structure and function in the soil microbiome of urban greenspaces’ published as research article in Science Advances, represents ‘the first global assessment’ of the issue.

 

It covered a global field survey in urban greenspaces and neighbouring natural ecosystems across 56 cities in 17 countries (including India) in six continents. In India, researchers from Banaras Hindu University joined the global study and looked at the urban greenspaces in Durgapur, Agra, and Mirzapur. Though Nagpur was not a part of it, the study records some interesting observations that may be applicable to the city and also expand the horizons of understanding, as far as looking at the urban greenspaces is concerned in the given push for development. The study’s lead author is Manuel Delgado-Baquerizo. The study found that the urban soils were ‘important hotspots’ for soil bacterial, protist, and functional gene diversity and also supported ‘highly homogenized microbial communities worldwide’. Summarising the findings, the authors of the study from various countries noted, “These urban ecosystems also showed higher proportions of genes associated with human pathogens, greenhouse gas emissions, faster nutrient cycling, and more intense abiotic stress than natural environments.

 

City affluence, management practices, and climate were fundamental drivers of urban soil communities.” The urban greenspaces studied were located mostly in ‘public parks and large residential gardens and comprised a mixture of open areas with lawns, scattered trees, patches of shrubs, and associated flowerbeds’. After conducting the field survey, the authors analysed the observations, and recorded the findings. According to the authors, the study indicates that urban greenspaces support a higher proportion of fungal parasites and plant pathogens ‘that are often economically important pests’. Of course, the researchers found that there were several factors that could influence the soil microbiome of urban greenspaces. They have listed socio-economic and climatic factors like ‘GDP per capita and high temperatures’. These factors influence the soil microbiome by ‘increasing environmental stress’ associated with ‘disturbance, pollution, and climatic stress’.

 

At the same time, the study found that urban greenspaces had ‘a higher proportion of plant and human pathogens, greenhouse gas emission, and nitrogen and phosphorus cycle genes’. The authors have mentioned about higher proportion of genes associated with ‘Mycobacterium virulence’, and Listeria and Diphtheria toxins, and ‘key antibiotic resistance genes’. Also, it found higher proportions of ‘viral genes’ in urban greenspaces than in natural ecosystems, ‘particularly in fertilized greenspaces’. At the same time, the researchers have made it clear that “extrapolating and linking the occurrence of particular soil microbial genes to human health needs to be further investigated in the future to better understand how those microbes found in urban soils may affect human health”. Some more important observations in the study are as follows: Urban soils across the globe harbor more similar microbiomes than would be expected from comparable analyses of soils from adjacent natural ecosystems; soils from urban greenspaces have higher proportions of fast-growing bacteria, algae, nitrifiers, and important plant pathogens, ‘which were particularly dominant in the warmer, more affluent, and more intensively managed greenspaces etc. As is part of general environmental awareness, apart from animals and plants, micro-organisms also form a critical part of the ecosystem on Earth. The study adds a new dimension of understanding of the ecosystem, especially greenspacesin urban areas in India including Nagpur, which are under threat in the name of development. It is for the policymakers and urban planners, environmentalists, and the society to take note of in the interest of sustainability. 

 

May it be Bharat Van, Ajni Vann, or Seminary Hills, Wardha Road, or any other greenspace in the city of Nagpur, everything appears to be under threat. For, several projects have either been planned or are at concept level, to destroy these urban greenspaces to replace these with development that includes cement-concrete structures. Against this backdrop, the study comes as an eye-opener. There are umpteen number of greenspaces in Nagpur, as has been shown by ‘The Hitavada’ through a series of photo-essays recently. Also, the society has shown its unwillingness to part with these greenspaces by way of filing more than 7,500 objections on record with Nagpur Municipal Corporation (NMC) registering protest against felling of trees in ‘Ajni Vann’. In response, some of the policymakers had said that there was no animal or wildlife in these urban forests. As has been pointed out in the new study, even the smaller urban greenspaces, public parks, and large residential gardens, are ‘important hotspots’ of local soil microbial diversity. Compared to parks and gardens, the greenspaces in Nagpur mentioned above are too large. Just imagine, how rich biodiversity do these greenspaces in Nagpur represent. There are trees, shrubs, bushes, grass, climbers, creepers, birds, flowers, and the whole invisible world of microbiome, which together influence the human life around.