Relating Urban Biodiversity to Human Health With the ‘Holobiont’ Concept

Abstract

A relatively unaccounted ecosystem service from biodiversity is the benefit to human health via symbiotic microbiota from our environment. This benefit occurs because humans evolved alongside microbes and have been constantly exposed to diverse microbiota. Plants and animals, including humans, are organised as a host with symbiotic microbiota, whose collective genome and life history form a single holobiont. As such, there are interdependencies between biodiversity, holobionts, and public health which lead us to argue that human health outcomes could be improved by increasing contact with biodiversity in an urban context. We propose that humans, like all holobionts, likely require a diverse microbial habitat to appropriate resources for living healthy, long lives. We discuss how industrial urbanisation likely disrupts the symbiosis between microbiota and their hosts, leading to negative health outcomes. The industrialised urban habitat is low in macro and microbial biodiversity and discourages contact with beneficial environmental microbiota. These habitat factors, alongside diet, antibiotics, and others, are associated with the epidemic of non-communicable diseases in these societies. We suggest that restoration of urban microbial biodiversity and micro-ecological processes through microbiome rewilding can benefit holobiont health and aid in treating the urban non-communicable disease epidemic. Further, we identify research gaps and some solutions to economic and strategic hurdles in applying microbiome rewilding into daily urban life.

Revegetation of urban green space rewilds soil microbiotas with implications for human health and urban design

“…One hypothesis for this rise is that urban children receive inadequate interactions with microbiotas from natural ecosystems, which are important for immune training during early life (Rook et al ; Gilbert et al ). Microbiome rewilding has potential to help reduce the rising noncommunicable disease burden in cities across the world by improving biodiversity exposure, particularly to natural microbiotas, in a cost‐effective and socio‐economically transcendent manner (Prescott et al ; Robinson et al ; Mills et al ).…”

“…As such, microbiome rewilding of urban outdoor spaces could provide “nature‐like” microbiota to urban homes. Therefore, it is important to understand the influence of revegetation on urban soil microbiota if this solution is to be offered as a cost‐effective and permanent source of diverse environmental microorganisms for early‐life exposure in the urban environment (Mills et al ).…”

Microbiome of root vegetables—a source of gluten-degrading bacteria

“…Why is gluten intolerance a growing concern if there are bacteria in the human GIT that can degrade harmful peptides? In contemporary Western societies, microbial diversity is decreasing with a redistributed balance (Rook 2013; Schnorr et al 2014;Moeller et al 2014;Mills et al 2019). The biodiversity hypothesis states that contact with natural environments enriches the human microbiome, promotes immune balance, and protects us from allergies and inflammatory disorders (Hanski et al 2012;Lehtimäki et al 2018;Haahtela 2019).…”

Does Soil Contribute to the Human Gut Microbiome?

“…Access to more biodiverse areas in urban environments, such as green spaces and parks, is related to health benefits regardless of socioeconomic status [63], which can be associated with the exposure to rich environmental microbiota. Hence, recent studies on urban re-wildering to improve the urban biodiversity of our living environments can be protective against immune disease by greater contact with a diverse set of environmental microbiota and consequently improve human health [64].…”