Soil organisms in parks and gardens

When we think of urban gardens and parks, we often think of the recreational services they provide that support our mental and physical health. However, these green spaces are semi-natural environments and a good ecological maintenance of them requires not only direct human care but also that offered by soil organisms.

The latter has been verified in a study carried out by a team that includes experts from the Higher Council for Scientific Research (CSIC) in Spain.

The team led by Manuel Delgado Baquerizo, head of the Biodiversity and Ecosystem Functioning Laboratory of the Institute of Natural Resources and Agrobiology of Seville (IRNAS), attached to the CSIC, has explored the role of soil biodiversity in maintaining the proper functioning of urban green areas.

Urban parks and gardens are home to a rich and diverse community of soil organisms, such as bacteria, fungi, protists, and invertebrates, that often go unnoticed in comparison to the showy plants and animals. “Soils with greater biodiversity also have more biogeochemical tools to allow the flow of energy and matter through the system. This biodiversity often goes unnoticed, but it plays a critical role in supporting One Health policies. in caring for the health of people, animals and the environment) and ecosystem services that are at the heart of the Sustainable Development Goals” explains Delgado Baquerizo.

soil genetics

The study provides novel evidence that soil taxonomic and genetic diversity is positively correlated with multiple dimensions of ecosystem functions in urban green spaces. This ranges from carbon sequestration and water regulation to control of plant pathogens and regulation of antibiotic resistance.

The authors of the study also show that the diversity of different types of organisms plays important roles in urban soils. For example, the biodiversity of soil invertebrates is especially important in supporting a large number of functions that work at high levels of functioning in urban green areas, while that of microbes helps to support basal levels of functioning.

“Considering their relatively larger body size and their ability to move about and process soil and litter, the biodiversity of soil invertebrates plays a fundamental role as engineers of the soil biome in parks and gardens,” explains researcher Haiyan Chu. from the Chinese Academy of Sciences (CAS).

The study also highlights the role of the most common species of our soils in supporting multiple functions. “Taking into account different aspects of soil biodiversity in urban planning is essential to ensure the sustainability of these ecosystems,” concludes Chu.

The new study has verified the fundamental role of soil biodiversity in maintaining the proper functioning of urban green areas. (Photo: Amazings/NCYT)

The importance of the soil biome

The main conclusion of the study is that soil biodiversity contributes to the performance of multiple ecosystem functions in urban green spaces.

But the study results also suggest that plant diversity has limited ability to influence soil ecosystem functions in parks and gardens. “Plants in urban green spaces are usually non-native species, coming from other places, often from other continents, and selected for their horticultural value rather than their ability to improve soils,” explains researcher Kunkun Fan, from CAS. .

Even so, “plant diversity is indispensable for other ecosystem services such as air purification, cooling, relaxation and beautification, in addition to basic ecosystem functions in natural ecosystems and, therefore, a fundamental component of green spaces. urban areas,” notes Professor Chu.

“Taking into account both plant and soil biodiversity in urban green spaces is key to supporting the sustainability of urban ecosystems and human well-being,” concludes Delgado Baquerizo.

An international investigation

To investigate the importance of soil biodiversity in maintaining urban green areas, the international team of scientists carried out the study in urban green areas of 56 municipalities on all continents and collected data on 18 ecosystem function surrogates and thousands species of soil microbes and fauna.

The study is titled “Soil biodiversity supports the delivery of multiple ecosystem functions in urban greenspaces”. And it has been published in the academic journal Nature Ecology and Evolution. (Source: Erika López / CSIC)