The role of green infrastructure quality for healthier and biodiverse cities

Abstract

In the upcoming decades, urban areas are expected to undergo significant expansion and transformation in order to accommodate the growing proportion of the world's population living in cities. This challenge presents a unique opportunity to rethink our cities and to shift from development patterns that have resulted in urban environments associated with environmental degradation and disconnection to nature and instead embrace transformative changes that promote healthier and more resilient cities where people and nature thrive. Urban green infrastructure is one of the main strategies to achieve this goal, given the potential of various types of green spaces and structures for delivering several ecosystem services benefitting not only human health and wellbeing but also biodiversity conservation. However, limited knowledge remains on the quality necessary to effectively provide the range of benefits expected by green infrastructure and also on possible trade-offs among beneficiaries with different needs. This doctoral thesis addressed these research gaps through two main questions: a) which and how green spaces characteristics are associated with mental health and wellbeing and wildlife support outcomes, and b) what are the synergies and trade-offs between human health and wildlife dimensions in urban green spaces. <br /> Through a systematic review, green space features that reportedly affected human mental health or wildlife support in previous studies were compiled. Then, the holistic One Health approach was used as a basis for the development of a framework connecting quality attributes of green spaces with human mental health and wellbeing and wildlife support in the urban context. <br /> To apply this framework in a case study in Brazil, the first step required a cross-cultural adaptation of the selected psychometric scales for measuring psychological restoration in the target population. Specifically, the Perceived Restorativeness Scale and the Restoration Outcomes Scale were translated into Portuguese and validated using samples from Porto Alegre and São Paulo cities located in southern and southeastern Brazil. The psychometric properties of both scales presented adequate internal consistency and model fit indexes, which remained consistent across participants’ gender and city of residency. Besides the intended application in this doctoral study, the provision of these newly-validated versions of such measures creates opportunity for the expansion of research on restorative environments in the poorly studied Global South, particularly in Brazil. <br /> In São Paulo, Brazil, a case study was carried out utilizing indicators and metrics identified in the systematic review to analyze the relationships outlined in the developed framework. The primary factors affecting user restorativeness were perceived safety and naturalness of parks. These perceptions were associated with park characteristics such as tree canopy coverage, presence of water bodies, and signs of vandalism. The presence of natural water bodies presented a clear mutual benefit for psychological restoration and support to birds (as representative of wildlife species). In contrast, whereas parks with higher tree canopy coverage offered greater potential for restoration to users, outcomes for bird assemblages were distinct depending on the metric selected. Summing up, the findings point out the necessity of a heterogeneous network of green spaces that are purposely planned and managed considering the synergies and trade-offs between human and wildlife requirements. <br /> In conclusion, the results of this doctoral thesis confirm the important role of green space quality in providing benefits to humans and animals. It also stresses the advantage of applying the One Health approach also to the urban context and, more specifically, to green infrastructure, enabling the identification of mutually beneficial effects and potential trade-offs between the environment, humans, and animals, and ultimately the implementation of truly multifunctional spaces and solutions.