Unraveling the complex relationship between urban biodiversity and humans: A Social-Ecological Framework for Urban Forests
RESEARCH SUMMARY
By Filipa Grilo
Filipa Grilo recently completed her PhD at the Center for Ecology, Evolution and Environmental Changes (CE3C) at the Faculty of Sciences of the University of Lisbon (FCUL). Her dissertation focused on urban biodiversity patterns and their implications for ecosystem services, employing innovative approaches to understand the interplay between social and ecological factors, and urban nature. Supervised by Timon McPhearson of the Urban Systems Lab, Filipa's research contributes significantly to the field of urban ecology, emphasizing nature-based solutions for climate change adaptation.
KEY TAKEAWAYS
A novel "Socio-Ecological Traits Framework" reveals crucial links between species traits, social filters, and ecosystem services in cities
Expanding and diversifying urban green infrastructure can transform cities, turning urban matrices into more than grey deserts—into thriving, diverse spaces
Urban trees form distinct functional groups that offer complementary ecosystem services
Local context, including tree canopy and urban morphology, significantly influences climate regulation
Social factors play a decisive role in shaping urban forest patterns and their benefits
Rethinking Urban Biodiversity
How do social and ecological factors shape the distribution of trees in our cities? This question drove my doctoral research, which aimed to unravel the complex relationships between urban biodiversity, social systems, and ecosystem services. Through a multi-scale analysis of Lisbon's urban forest, we discovered patterns that challenge conventional wisdom about urban ecosystems.
A Framework for Understanding Urban Nature
At the heart of this research lies the "Socio-Ecological Traits Framework," a new approach to understanding how cities shape biodiversity. This framework bridges the gap between species characteristics, social influences, and the services these urban ecosystems provide. By examining these relationships systematically, we gained insights into how urban environments filter and shape biological communities.
The Socio-Ecological Traits Framework.
Source: A trait-based conceptual framework to examine urban biodiversity, socio-ecological filters, and ecosystem services linkages. Npj Urban Sustainability, 2(1), Article 1. Grilo, F., McPhearson, T., Santos-Reis, M., & Branquinho, C. (2022).
Surprising Patterns in Lisbon's Urban Forest
Our analysis of Lisbon's street trees revealed unexpected patterns across multiple scales. Counter to common assumptions, we found the highest values of tree abundance and diversity in the most urbanized areas. However, these areas were often dominated by a select few species, raising important questions about resilience and the need for diversification in urban forest management.
Images of locations in Lisbon without street trees (A), with street trees in a pocket park (B), with a high abundance of street trees with low diversity (C), and with a high abundance of street trees with high diversity (D). Photos by Filipa Grilo.
Source:The influence of social-ecological factors in urban trees at multiple scales. Science of The Total Environment, 172552.Grilo, F., McPhearson, T., Nunes, A., Aleixo, C., Santos-Reis, M., & Branquinho, C. (2024). Where the not-so-wild things are in cities?
Beyond Numbers: Understanding Functional Groups
One key contribution of our research was the identification of distinct functional groups among urban trees. These groups, characterized by different traits and adaptations, provide complementary ecosystem services. Understanding these functional relationships helps urban planners create more resilient and beneficial urban forests.
Street trees’ functional groups in Lisbon and their association with different social and ecological factors.
Source: Filipa Grilo
Climate Connection
Our findings highlighted the crucial role of tree canopy and urban morphology in regulating local climate. This understanding has direct implications for urban planning and climate adaptation strategies, particularly as cities worldwide face increasing heat stress and other climate-related challenges. These results supported the Municipality of Almada's successful LIFE Programme application, leading to the COOLife project which is now implementing nature-based solutions including microforests, green roofs, and green walls—interventions that will help mitigate urban heat risks for over 10,000 residents.
Climate regulation services provided by urban parks in Almada, Portugal.
Source: Using green to cool the grey: Modelling the cooling effect of green spaces with a high spatial resolution. Science of The Total Environment, 724, 138182. Grilo, F., Pinho, P., Aleixo, C., Catita, C., Silva, P., Lopes, N., Freitas, C., Santos-Reis, M., McPhearson, T., & Branquinho, C. (2020).
From Research to Practice
The insights from this research are now informing real-world applications. In my current role with the Cities for Climate Network, I'm evaluating nature-based solutions for carbon removal across 20 Portuguese municipalities and regions at the IN+ Center for Innovation, Technology and Policy Research (IN+). This work, part of an initiative to achieve climate neutrality by 2030, demonstrates how understanding urban biodiversity patterns can contribute to creating more sustainable cities.
Research Impact and Collaboration
The success of this research was strengthened through international collaboration, particularly through the NATURA network's Urban Ecological Resilience Working Group and time spent at the Urban Systems Lab. These connections provided opportunities to share findings at international conferences and contribute to broader discussions about urban ecological resilience.
Looking Forward
As cities continue to grow and face environmental challenges, understanding the social-ecological dynamics of urban forests becomes increasingly critical. This research provides a framework for creating more resilient, sustainable, and livable cities through informed management of urban biodiversity.
Published work from this research can be found in:
Grilo, F., McPhearson, T., Santos-Reis, M., & Branquinho, C. (2022). A trait-based conceptual framework to examine urban biodiversity, socio-ecological filters, and ecosystem services linkages. Npj Urban Sustainability, 2(1), Article 1. https://doi.org/10.1038/s42949-022-00077-7
Grilo, F., McPhearson, T., Nunes, A., Aleixo, C., Santos-Reis, M., & Branquinho, C. (2024). Where the not-so-wild things are in cities? The influence of social-ecological factors in urban trees at multiple scales. Science of The Total Environment, 172552. https://doi.org/10.1016/j.scitotenv.2024.172552
Grilo, F., Pinho, P., Aleixo, C., Catita, C., Silva, P., Lopes, N., Freitas, C., Santos-Reis, M., McPhearson, T., & Branquinho, C. (2020). Using green to cool the grey: Modelling the cooling effect of green spaces with a high spatial resolution. Science of The Total Environment, 724, 138182. https://doi.org/10.1016/j.scitotenv.2020.138182
