Why the Future of Cities May Depend on Invisible Life Beneath the Grass

Nguyen Thi Nguyet Nuong

East Asian University of Technology

Contract: nuongntn@eaut.edu.vn

21-05-2026

© Wix

Cities are often seen as symbols of human progress. As urban areas continue to expand, they generate economic opportunities, innovation, and social development. Yet this growth also comes with environmental costs. Urbanization contributes to biodiversity loss, habitat fragmentation, pollution, and intensifying urban heat island effects. Together, these changes threaten not only ecological systems but also human well-being (Tong et al., 2022; Li et al., 2022).

To address these challenges, urban planners increasingly rely on green spaces as a form of natural infrastructure. Parks, urban forests, and green corridors help cool cities, filter pollutants, store carbon, support biodiversity, and create spaces where people can exercise, learn, and reconnect with nature (Hunter et al., 2019; Kraemer & Kabisch, 2022; Wang et al., 2024).

However, when people think about urban green spaces, they often focus on what they can see: trees, lawns, flowers, and landscapes. Much less attention is paid to what lies beneath the surface.

The ecological capacity of urban green spaces depends on their soils. Soil is not simply dirt holding plants in place. It is a complex living system filled with enormous microbial communities that perform essential ecological functions. These microscopic organisms decompose organic matter, recycle nutrients, stabilize soils, suppress pathogens, and regulate greenhouse gases (Wagg et al., 2014; Nugent & Allison, 2022). In many ways, soils act as invisible engines supporting urban ecosystems.

Yet urban soils often carry scars from the history of city development. Construction activities frequently remove nutrient-rich topsoil, compact the ground with heavy machinery, and replace natural soil with artificial fill materials low in organic matter and microbial diversity. Intensive maintenance practices, such as excessive mowing and pesticide use, can further disturb these systems. Consequently, urban soils are frequently viewed as biologically simplified and functionally degraded environments.

But this perspective may overlook an important possibility: cities may possess greater ecological potential than previously assumed.

A recent study published in Landscape and Urban Planning examined soil properties and microbial communities across 30 urban green spaces of different ages in Seoul, South Korea. The researchers found that older green spaces showed substantial ecological improvements. As sites aged, soil organic matter accumulated, microbial diversity increased, and soil functions became more complex. Older sites contained more beneficial plant-associated microbes and organisms involved in carbon decomposition, while microbes associated with pathogens and pollutants declined. The findings suggest that urban green spaces may not be static systems but developing ecosystems capable of gradual recovery (Yang et al., 2026).

Urban green spaces cannot be understood simply as collections of trees, grass, or soil particles. Their functions emerge from interactions among plants, microbes, management practices, human activities, climate conditions, and socioeconomic environments. Adding a tree to a city is not merely placing vegetation into a space. It introduces new relationships into an existing network of interactions (Khuc & Nguyen, 2026). Small changes—such as increasing organic matter in soils—can gradually reshape microbial communities, which may then alter nutrient cycles, improve soil structure, strengthen ecosystem resilience, and eventually influence broader ecological functions (Vuong, 2025).

The future of sustainable cities may therefore depend not only on what grows above ground, but also on understanding the hidden systems beneath our feet. After all, healthy cities may ultimately emerge from healthy relationships—many of which are too small for us to see (Nguyen & Ho, 2026).

References

Hunter, R. F., et al. (2019). Environmental, health, wellbeing, social and equity effects of urban green space interventions: A meta-narrative evidence synthesis. Environment International, 130, 104923. https://doi.org/10.1016/j.envint.2019.104923

Khuc, V. Q., & Nguyen, M. H. (2026). Cultural Additivity Theory. Available at SSRN 6767760. https://ssrn.com/abstract=6767760

Kraemer R. & Kabisch, N. (2022). Parks under stress: Air temperature regulation of urban green spaces under conditions of drought and summer heat. Frontiers in Environmental Science, 10, 849965. https://doi.org/10.3389/fenvs.2022.849965

Li, G., et al. (2022). Global impacts of future urban expansion on terrestrial vertebrate diversity. Nature Communications, 13(1), 1628. https://doi.org/10.1038/s41467-022-29324-2

Nguyen, M. H., & Ho, M. T. (2026). The absurdist approach to unveiling possible paradoxical thinking for innovative socio-psychological research. MethodsX, 16, 103910. https://doi.org/10.1016/j.mex.2026.103910

Nugent, A. & Allison, S. D. (2022). A framework for soil microbial ecology in urban ecosystems. Ecosphere, 13(3), 3968. https://doi.org/10.1002/ecs2.3968 

Tong, S., et al. (2021). Urban heat: An increasing threat to global health. BMJ, 375(2467), n2467. https://doi.org/10.1136/bmj.n2467 

Vuong, Q. H. (2025). Wild Wise Weird. AISDL. https://books.google.com/books?id=C5dDEQAAQBAJ

Wagg, C., et al. (2014). Soil biodiversity and soil community composition determine ecosystem multifunctionality. PNAS, 111(14), 5266-5270. https://doi.org/10.1073/pnas.1320054111

Wang, D. et al. (2024). Urban green infrastructure: Bridging biodiversity conservation and sustainable urban development through adaptive management approach. Frontiers in Ecology and Evolution, 12, 1440477. http://dx.doi.org/10.3389/fevo.2024.1440477

Yang, Y., et al. (2026). Increasing biodiversity and ecosystem functions along an age gradient of urban greenspaces. Landscape and Urban Planning, 273, 105672. https://doi.org/10.1016/j.landurbplan.2026.105672