How to assess the benefits of Nature-Based Solutions? Building Evidence from Cost Benefit Analyses in Latin America and Europe

Co-authors: Daniel Kozak, Mariana Giusti, Hayley Henderson

This paper aims to contribute to the debate on the advantages of implementing Nature-Based Solutions (NbS) to solve urban problems. For this purpose, three assessments for pilot projects built in cities in Latin America and Europe are presented were Cost Benefit Analysis (CBA) was used. The studied projects used NbS as a central design strategy, which represented an innovation regarding the standard solutions used in these cities, based on traditional engineering (commonly known as grey infrastructure).The selection of pilot projects was made among the participants of the CONEXUS research project (EU Horizon 2020 programme). A multidimensional evaluation of all Life-lab pilots was carried out, based on criteria of territorial distribution, NBS types, ecosystem services provided, proposed indicators to measure performance and the capacity of the main pilot actors to participate in a CBA process. On these bases, three pilot projects were selected for an in-depth analysis: the construction of rain gardens in the Medrano stream basin (San Martín, Argentina), the incorporation of green spaces in the Livable Valddoco project (Turin, Italy) and the implementation of the Urban Allotments programme (Barcelona, Spain).
In order to carry out the CBAs, the cost of production of the NbS implemented was calculated and compared to the benefits they generate, based on the monitoring and measurement of the different ecosystem services they provide. The limitations of this methodology are clear: not all ecosystem services can be parameterised and quantified through indicators; secondly, not all of them can be monetised. However, it is worth discussing the productivity of this approach in order to compare the benefits of NbS with regard to their implementation costs; with regard to other traditional (grey) methods or solutions to solve the same problems; and to facilitate the decision-making process.

Socioeconomic impact of urban gardens in Barcelona

Co-authors: Marc Montlleo, Adrián Cabezas, Arnau Lluch, Ismael Pérez-Franco

The objective of the work is to present an initial assessment of the socioeconomic impact of urban gardens in the city of Barcelona. The city of Barcelona has 47 urban gardens, covering 75,826 square meters and involving 1,294 direct users. The core of the assessment focuses on the following points, selected based on economic impact and availability of information: subjective benefit to users, carbon capture, and direct production. The total estimated socioeconomic value generated by these three variables in the 47 gardens of Barcelona amounts to €2,880,629 annually. This represents an average annual benefit of €2,261 per user or €61,290 per garden. However, two dimensions with high impact could not be assessed: the impact on human health and urban biodiversity. The assessment was carried out within the framework of the CONEXUS project with the support of Barcelona Regional, and fieldwork was conducted in March 2023.

Nature based solutions and ecosystem services in Latin American and European cities: insights from a Citizen’s perception of value

Co-authors: Geovana Mercado, Tom Wild, Thomas Randrup, Alexis Vasquez, Jaime Hernandez-Garcia, Riccardo Saracco, Paulo Pellegrino, Giuliano Locosselli, Teresa Verellen, Iar Mek, Paula Nicolau, Marc Montlleo and Corina Basnou.

Urban centers across Latin America and Europe, despite their geographic and cultural disparities, are being confronted with similar environmental and societal concerns. Issues such as increasing temperatures, reduced air and water quality, and a general vulnerability to extreme weather events are compelling cities on both continents to explore the potential of Nature-based Solutions (NBS) and Ecosystem Services (ESS) to address these challenges. Nature-Based Solutions and the provision of ESS have emerged as central strategies to mitigate environmental risks while enhancing the quality of life for urban residents.
However, the motivations, strategies, and outcomes associated with implementing NBS may differ significantly between the two regions, reflecting variations in historical, cultural, economic, and political context. Also, citizens’ aspirations and needs in terms of greenspaces is place-specific and dependent on socio-economic contexts. This research aims to identify and study the citizens values associated with NBS and ESS within the different contexts of five Latin American and European cities, (Buenos Aires, Barcelona, Santiago de Chile, Lisbon and Sao Paulo). These cities are all implementing NBS and share a broader goal of implementing re-greening processes across their territories. They also exhibit different socio economical traits and natural conditions though face similar environmental dilemmas.
We apply a PPGIS approach to survey the experiences, preferences, and perceptions of residents to elucidate the environmental and social values attributed to these nature-driven interventions. We aim to respond the following research question:
How do citizens value Nature based Solutions and Ecosystem Services in Latin American and European cities?
By answering this question, we expect to contribute to a more holistic understanding of how cities can leverage the inherent value of nature to build sustainable, resilient, and thriving urban environments.

Economic and Social Impacts of Nature Based Solutions in Informal Settlements

Co-author: Ingrid Novoa

Latin America is the most urbanised region in the world, with almost 80% of the population living in urban conglomerates (UN, 2018). This urbanisation has largely occurred through informal urbanisation, with limited access to goods and services and severe spatial, environmental and socio-economic inequalities (Escobedo et al., 2015). Informal settlements, usually located in periurban areas, are a characteristic feature of Colombian cities, where in Bogotá, for example, more than 50 % of the city has grown from some informal pattern (urban and/or housing), and about 30 % of the city is considered informal (Hernández-García, 2016).Nature-Based Solutions as actions to protect, sustainably manage and restore restored or modified ecosystems have emerged to effectively address societal challenges, while adaptively and simultaneously providing human well-being and biodiversity benefits (IUCN, 2016). They, thus, make a considerable contribution to the challenges cities face around the consequences of climate change and biodiversity loss, and particularly to informal settlements where the consequences of socio-ecological conflicts are most acute. But little is known about the economic and social impacts that these solutions actually bring to vulnerable communities in terms of their livelihoods.
This presentation, taking as a case study the Bogota Life Lab of the CONEXUS project, and the NBS pilot interventions that have been co-created with communities in the peri-urban areas of the north and south of the city, explores the economic and social impacts of these interventions and discusses their valuation in broader terms. The paper seeks to highlight the value of NBS in sectors of informal urbanisation, in order to contribute to thinking about other more sustainable forms of urban expansion and the role that NBS can play.

Stormwater management in cities to cope with multiple extreme events: Socio-economic evaluation of nature-based solutions to support climate-resilient urban planning

Co-authors: Ulf Stein, Flora Dicke, Hannes Schritt

Urban areas are particularly affected by extreme weather events such as flooding and heat waves. High levels of land sealing and building density exacerbate the flood risk, the heat islands effect and droughts impacts in the summer months. Modern stormwater management and nature based solutions (NBS) are considered highly relevant components of water-sensitive urban planning to mitigate the climate impacts. NBS shape urban space in the spirit of the ""sponge city"" idea. They can have multiple positive effects on environmental, social and economic challenges, including health, biodiversity, recreational opportunities, or job creation.

Due to the multiple effects of NBS, an assessment of costs and benefits of NBS is an important decision-making tool at the local level. The integration of social and environmental dimensions and an overall societal perspective is essential to ensure a broader overview of NBS effects. The challenge is often that private investors do not include these additional benefits in their considerations because it is not representing a direct benefit. Often, however, it is the overall consideration of all effects that changes the relationship between costs and benefits and argues for the realization of the NBS investment project.

Based on literature review and a stakeholder engagement process with cities in Germany, a socio-economic assessment for NBS at the district level is designed and implemented. It had to deal with the challenges of measure’s local effectiveness and data availability at district level. The approach includes a multi-criteria analysis to cover costs and benefits and other implementation aspects in a broader way. Furthermore, methods for the monetization of benefit components on local level are developed. The use of monetized benefits for urban planning, the additional value e.g. for communication or funding possibilities, and the approach’s robustness is discussed critically with local stakeholders.

Methodology framework for NbS location and selection according to biophysical and economic benefit values

Co-authors: Juan Pablo Rodríguez Sánchez

Cities increasingly recognize the potential of NbS to tackle urban challenges and contribute to global goals. However, gaps remain in the tools and knowledge needed for effective decision-making on deploying NbS in urban areas. One key challenge is understanding the role and value of the ecosystem services that NbS generate for cities. Lack of information on NbS makes it difficult for urban planners to identify where and how these solutions could effectively address specific challenges. As such, there is increasing demand for access to resources, guidance and tools to help support the design, implementation and funding of NbS. This presentation outlines a project and a tool that help meet this demand:

NetworkNature is a ‘network of networks’ and one-stop resources for everyone interested in NbS, including local and regional authorities, policy makers, civil society, businesses and investors. The project aims to raise awareness, share knowledge and build capacity about NbS to accelerate their uptake in business, science, policy and practice along the policy priorities of the European Green Deal.

Urban Ecosystem Accounting (Urban EA) is a tool that can help city planners identify where their ecosystem assets are, the ecosystem services they provide and who benefits from them. Urban EA can help identify which municipal budgets could support NbS implementation. For instance, demonstrating that NbS can enhance the resilience of transport routes while offering recreational opportunities for local communities could build the case for using both infrastructure and social budgets for NbS implementation and maintenance.

UNEP-WCMC will introduce both the NetworkNature project and a four-step guide for performing urban EA using the SEEA-EA framework. The presentation will emphasize how these two different types of resource can help urban planners integrate NbS into decision-making, understand public area values, and promote equitable access to ecosystem services.

Accounting for nature in planning: Urban Ecosystem Accounting for integrating Nature-based Solutions in cities.

Cities increasingly recognize the potential of NbS to tackle urban challenges and contribute to global goals. However, gaps remain in the tools and knowledge needed for effective decision-making on deploying NbS in urban areas. One key challenge is understanding the role and value of the ecosystem services that NbS generate for cities. Lack of information on NbS makes it difficult for urban planners to identify where and how these solutions could effectively address specific challenges. As such, there is increasing demand for access to resources, guidance and tools to help support the design, implementation and funding of NbS. This presentation outlines a project and a tool that help meet this demand:
NetworkNature is a ‘network of networks’ and one-stop resources for everyone interested in NbS, including local and regional authorities, policy makers, civil society, businesses and investors. The project aims to raise awareness, share knowledge and build capacity about NbS to accelerate their uptake in business, science, policy and practice along the policy priorities of the European Green Deal.
Urban Ecosystem Accounting (Urban EA) is a tool that can help city planners identify where their ecosystem assets are, the ecosystem services they provide and who benefits from them. Urban EA can help identify which municipal budgets could support NbS implementation. For instance, demonstrating that NbS can enhance the resilience of transport routes while offering recreational opportunities for local communities could build the case for using both infrastructure and social budgets for NbS implementation and maintenance.
UNEP-WCMC will introduce both the NetworkNature project and a four-step guide for performing urban EA using the SEEA-EA framework. The presentation will emphasize how these two different types of resource can help urban planners integrate NbS into decision-making, understand public area values, and promote equitable access to ecosystem services.

Blue Economy in Coastal Cities

Co-author: Kieran Birtill, Dr Sara Candiracci

Oceans are spaces of complex socio-economic and environmental interactions, processes, challenges and opportunities. They are key to the economic development of coastal countries, the direct provision of livelihoods for coastal populations and indirect livelihoods of many others. Oceans are in fact key to all life on earth, absorbing approximately 25 percent of all CO2 emissions. However, insufficient consideration for environmental and social sustainability are putting the ocean’s resources at risk, hampering the socioeconomic benefits that the ocean might deliver for future generations. The blue economy - a concept concerning sustainable use of ocean resources – is of upmost importance. According to estimates by the Global Ocean Commission, ocean resources contribute to the livelihoods of 350 million people. However, climate change, pollution and insufficient consideration for environmental and social sustainability are putting the ocean’s resources at risk, hampering the socio-economic benefits that the ocean could deliver for future generations.
The term ‘blue economy’ seeks to promote economic growth, responsible production and consumption, social inclusion, and the preservation or improvement of livelihoods from ocean resources, while at the same time ensuring environmental sustainability of oceans, coastal areas, and other waterfront spaces.
This study presents global best practice case studies to help blue economy stakeholders in future planning and project implementation, promoting nature-based solutions across blue economy sectors, as applicable, such as coastal tourism, operational environment, and climate change adaptation and mitigation.
The blue economy is a concept gaining growing attention and awareness in both academic and policy circles. This study is therefore timely, and these case studies are intended to inform and inspire blue economy stakeholders involved with planning and implementation locally, nationally, and globally.

Financing NbS in urban areas: where are we at in the LAC region

Transforming policy into action: linking and coordinating international financing for the design of public policy on urban NbS and its implementation in Chile

Chile is developing a coordinated strategy to design a Green Infrastructure and NbS Roadmap for urban and peri-urban areas, thanks to the linked financing from the Green Climate Fund (GCF) and the Global Environmental Facility (GEF) and the technical support of the FAO.

Through the GCF's Readiness Program, the Ministry of Housing and Urbanism, in collaboration with the Ministry of the Environment, has requested a grant for the design of this Roadmap. This involves the creation and strengthening of a multilevel and multi-actor governance mechanism for the design and implementation of the Roadmap, the generation of evidence for decision-making and definition of the Roadmap, and a technical-participatory work process and financial analysis to draft the proposal.

Concurrently, this initiative will unfold alongside the formulation of a GEF-funded project within the framework of the Sustainable Cities Integrated Program. The primary objective of this project is to enhance Nature-based Solutions and Green Infrastructure networks, fostering biodiversity conservation while addressing climate change in urban and peri-urban areas throughout Chile. By tackling institutional, regulatory, and market-level barriers, the project aims to propel cities towards the integration of NbS and green infrastructure in urban planning and development. Through pilot activities in four cities spanning diverse climatic ecoregions across the country, the project's implementation will commence sequentially upon the conclusion of the Roadmap.

This strategic alignment of multilateral efforts and financing is designed to advance the promotion and implementation of an innovative public policy, securing fresh resources for its swift execution.

Network of regional infrastructures for the Federal District: opportunities for sustainable economic development

Co-authors: Maria do Carmo de Lima Bezerra, Juliana Machado Coelho, Tatiana Reinehr de Oliveira

Assertive forms of landscape planning leading to socio-ecological well-being promotion has become notorious in discussions towards climate adaptation plans, operationalization of Sustainable Development Goals – SDGs and pressing creation of a regulated Brazilian carbon market. Within the Federal District (FD), public and private agents have developed plans and projects aimed at increasing territorial resilience, such as reducing greenhouse gas emissions, decarbonizing agriculture and expanding tree planting. This research proposes the spatialization of an assertive multi-scale planning and design strategy, in the context of the Brazilian Cerrado Biome. As an alternative to the traditional model based on gray infrastructure, it suggests the structuring of a multi-scale network and multifunctional green infrastructures based on the mapping of carbon and water flows in the territory. This allows to reach different demands and efforts for environmental recovery based on landscape ecology analyzes. Through Geodesign application, connected with other layers of information from official databases, the proposal was discussed with stakeholders in a co-designed process leading to defining the general contours of a regional green infrastructures network for FD territory. Both environmentally protected and new potentially increasing carbon sequestration areas were considered through pragmatic interventions in the São Bartolomeu Hydrographic Basin. In the end, it was possible, not only to increase the territorial canopy, but also to get a mosaic composed of hotspots, ecological corridors, and ecological support patches, traced by structural and functional metrics using an Ecology Restoration approach. The results support climate adaptation and sustainable development policies, generating an exponential increase in the biodiversity flow throughout the proposed mosaic and beyond Federal District borders. There are, therefore, new opportunities for sustainable economic development based on the operationalization of the proposed mosaic for territorial planning and socio-ecological development.

Valorisation of Nature-based Solutions – A step-by-step guide

Co-authors: Federica Di Cagno, Cecil Konijnendijk, Tom Wild

Nature-based solutions (NBS) are increasingly recognized worldwide for their effectiveness in addressing urban challenges while promoting environmental sustainability and community well-being. However, decision-making regarding NBS funding and implementation tends to be centralized within public authorities and government bodies, often overlooking input from key stakeholders such as local communities, NGOs, and small to medium enterprises. This limited engagement, coupled with a narrow focus on economic returns and insufficient awareness of their broader benefits, often hinders the realization of the full potential of NBS. In response to these challenges, this guide aims to inform urban stakeholders on the knowledge needed to develop compelling business cases for NBS implementation. The guide adopts a seven-step valorization approach, aiming to expand traditional economic perspectives and leverage NBS values across environmental, economic, social, and health dimensions. Drawing upon research findings and experiences from the Horizon Europe CONEXUS project, the guide offers practical tools and methodologies for building a compelling business case for NBS, having a clear vision of the urban challenges to be addressed, the value the NBS will bring, and how to create and capture this value. Tested in real-world scenarios across five Life Labs, part of the CONEXUS project, the methodologies outlined in the guide have been adapted to diverse socio-economic and political contexts. This adaptation accounts for challenges related to data availability and stakeholder involvement inherent in the co-creation of NBS. Central to the methodology is the imperative to promote a continuous stakeholder’s engagement throughout the entire valorization process, recognizing and leveraging the multidimensional values of NBS and securing long-lasting social and financial support.

Developing and classifying urban biomes as a basis for nature-based solutions

Co-authors: Tom Wild, Adriana Afonso Sandre, Paulo Renato Mesquita Pellegrino, Carlos Alberto da Silva Filho, Marcos Silveira Buckeridge, Giuliano Maselli Locosselli

Urbanization is a major driver of environmental change, which calls for multifunctional and comprehensive actions such as Nature-based Solutions (NbS). They are “inspired and supported by nature… and must benefit biodiversity and support the delivery of a range of ecosystem services”. But what nature should one aim for? We tested the hypothesis that local vegetation may not always be the best source of inspiration, as environmental changes impact both extant conditions and species suitability for restored ecosystems. We analyzed the megacity of Sao ˜ Paulo, where laws promote the use of species from the local Atlantic Forest biome. We trained a Linear Discriminant Analysis to classify the Brazilian biomes and predicted the biomes’ correspondence considering city’s vegetation cover and climate. With 80% accuracy, the model predicted correspondence with the Atlantic Forest in 57% of the city, while 43% is better represented by the Cerrado, a dense Tropical Savanna biome. Cerrado species are naturally adapted to higher insolation, temperature and more seasonal precipitation, and they can parallel the ecosystem services of the Atlantic Forest. To help guide NbS implementation, we consider four “urban biomes”: Atlantic Forest, Seasonally Flooded Atlantic Forest, Cerrado, and the Seasonally Flooded
Cerrado, whose dynamics seem to depend mainly on changes in the proportion of dense vegetation cover. We then discuss possible examples of NbS in the city. The urban ecosystem restoration could benefit from such natural and dynamic processes in which the Cerrado could act as a transient urban biome in the way of restoring the urban forests through soil horizon development and species succession followed by the densification of the vegetation whenever this planting scheme is possible.

Citizen Stewardship of Street Tree Pits Promotes Urban Biodiversity and Public Health

Co-authors: Dr. Rita Sousa Silva; Dr. Ashby Lavelle Sachs; Prof. Dr. Harmut Fünfgeld

Nature-based solutions (NBS) are one approach that may offset some of the environmental challenges associated with urban living and climate change; the urban forest is a NBS found in cities around the world. Street trees are an essential component of the urban forest and provide a wide range of ecosystem services for human health and the environment. Citizen stewardship–the act of an individual taking care of the local environment–can not only play a significant role in street tree maintenance and longevity, but can also foster volunteer engagement and community cohesion. This transdisciplinary project involving two University of Freiburg departments (Geobotany and Geography of Global Change), the University Clinic of Freiburg Institute of General Medicine, the city of Freiburg, and the Freiburg Eco-station, aims to understand: (1) To what extent stewarding a street tree via street tree pit gardening affects urban biodiversity, specifically plant diversity and species richness. (Method: Measuring and comparing plant diversity in “pairs” of gardened and non-gardened (wild) tree pits.) and (2) To what extent street tree pit gardening affects wellbeing, sense of place, and nature-connectedness of citizen stewards. (Methods: Survey and Qualitative Interviews: 5 questions assessing wellbeing; 6 questions assessing nature-connectedness; 9 questions assessing sense of place; 3 questions assessing perceived biodiversity.) Results: We measured plant diversity in c. 300 street tree pits gardened by citizen stewards and found significantly more plant diversity and species richness in gardened tree pits compared to non-gardened tree pits. Through surveys and interviews we found that the process of gardening a tree pit has a positive impact on the wellbeing, nature-connectedness, sense of place, and community cohesion of citizen stewards. This study suggests that tree pit citizen stewardship is an important NBS that promotes urban biodiversity and public health.

Biodiverse, attractive and sustainable? Public Perception of and Preference for Designed Naturalistic Urban Planting in China

Co-authors: Dr. Helen Hoyle; Dr. Nicola Dempsey, Prof. James Hitchmough

Naturalistic urban planting, characterized by the mimicry of natural structures and well-adapted plants, is a Nature-Based Solution (NBS) with the potential to enhance biodiversity, mitigate climate change, and improve human well-being. Gaining prominence in Europe and North America, this approach to urban plantingis increasingly recognized by China, a major carbon emitter, as a means to achieve carbon neutrality and foster sustainable environmental improvement at a cost-effective rate.. Yet if the human wellbeing effect of this form urban planting is to be optimised, it must be accepted and enjoyedby diverse urban publics. This study aimed to explore public perception and preferencefor designed naturalistic planting in China to inform future urban landscape design and management. A questionnaire was distributed to 1,400 visitors of urban parks and EXPO show gardens in Beijing and was complemented by semi-structured interviews with 35 participants. The results show a favourable reception of naturalistic plantings in larger parks, where they are valued for their ecological and aesthetic qualities, and their alignment with environmental policies. However, perceptions of disorder were noted in smaller show gardens, highlighting the challenges of adapting these designs to different urban contexts. Furthermore, the study revealed that demographic factors including gender, age, education level, income, and professional background significantly influence preferences. This finding emphasizes the necessity of adopting inclusive and diverse methodologies when applying NBS in urbansettings. These insights enhance the understanding of NBS in urban landscapes, particularly in the context of China’s environmental strategies, and provide valuable guidance for urban planners, landscape designers, and policymakers, stressing the importance of public perception and adaptive approaches in the successful integration of NBS in urban landscapes.

Contribution of ecological research in urban planning and development

Climate control of the growth of native tree species in two contrasting urban parks from São Paulo, Brazil.

Co-author: Giuliano Maselli Locosselli

Urban forests play a fundamental role in adapting cities to climate change. Trees provide ecosystem services that help mitigate air pollution, flooding, and heat islands, besides being a carbon sink. The provision of these ecosystem services is species-dependent, and knowing their growth potential under various climate conditions is a fundamental step in planning resilient urban green areas. São Paulo is a megacity that already faces the impacts of climate change. The city is located in the Atlantic rainforest, one of the world's biodiversity hotspots. Such high biodiversity translates into a plethora of natural tools to promote a resilient city. However, knowledge about the growth of native species in the urban context is still scarce. To understand how urban climate influences tree growth, we monitored seven native species in two contrasting parks in the city of São Paulo, a recreational public park with a planted woodland, and a large Atlantic Rainforest Patch surrounded by the urban fabric. Growth was monitored using digital band dendrometers, whose results were analyzed together with data on trees’ phenology and local climate data. The species were monitored for two growing seasons. Results revealed significant differences in the seasonality of growth, growth onset and dormancy periods that reflect in the species’ average growth rates and biomass gain. Differences in growth rate were not that evident between the trees growing in the planted woodland and the native forest patch, while the growth rate was significantly higher in isolated trees growing in the recreational public park. These findings support the necessity of planning urban green areas taking into account the biodiversity to optimize ecosystem services like carbon sequestration.

Co-Producing Nature-Based Solutions to mitigate pollution, improve biodiversity, and foster ecosystem processes in urban streams within vulnerable social contexts

Co-authors: Barbara M: Gómez, Sebastián Gómez Lugo, Camila Saveika, Martin Saraceno

The expansion of metropolitan areas in Latin America imposes significant negative impacts on aquatic ecosystems, placing them at the center of demands from popular and socio-vulnerable sectors of society. Addressing urban streams within a social-ecological paradigm, through a co-production approach, and situated within a nature-based solution framework can serve as a strategy to link ecological restoration outcomes more effectively with current management practices. Here, we present a transdisciplinary approach outlining actions and results achieved during a long-term co-production experience centered on the ecological rehabilitation of the San Francisco Stream (Claypole, Buenos Aires). The period analyzed covers the years 2013-2023, during which the established connection with a social organization has led, since 2018, to the development of a transformative urban space named "Proyecto Hábitat Claypole". The successful co-production work has primarily focused on the co-implementation and evaluation of ecological management activities along a 1.4 km section of the stream. These actions include the reintroduction of native riparian and aquatic vegetation, geomorphological alterations to the habitat, co-production of biofilters to reduce domestic pollutants from urban drainage, establishment of a local nursery managed by workers of the social organization, and redesigning the landscape based on ecological and social knowledge and preferences. We evaluate the success through improvements in native vegetation and microalgae biodiversity, enhanced ecosystem processes such as nutrient retention, and socio-ecological contributions such as flood mitigation and water quality improvements. Additionally, we conclude by analyzing the project's impacts to facilitate transformative changes in pre-existent hydraulic mental models at the social and management level and explore prospects for creating green employment opportunities within the social economy sector.

Preference for green roof vegetation: aesthetic and restorative qualities

Co-authors: Åsa Ode Sang; Ishi Buffam

Green roofs are vegetation systems that are particularly well-suited to dense urban environments, and can contribute to multiple ecosystem services that support both biodiversity, human health, and contribute to perceived aesthetic qualities. In this study we set out to explore the effects of different types of green roof vegetation, along with seasonal variations, on visual aesthetical experiences, restorative effects as well as perceived biodiversity. An online photo elicitation survey was conducted using standardised photographs of a selection of green roofs in Malmö, Sweden, during three different seasons. In the survey, members of the public were asked to evaluate different aesthetic qualities, human well-being and to estimate perceived biodiversity and the stress reducing capacity for each photograph.Results showed statistical differences among roof types and by season in terms of perceived aesthetic qualities where the observed differences in perceived values were largely driven by the colour frame of the green roof. Restorative effects and perceived biodiversity follows the same trend. Lower scores were associated with a high percentage of red and brown-red shades, while higher scores were associated with green, white, and a lower percentage of red and brown-red shades. The results of the study have the potential to inform green roof management strategies and landscape planners.
Keywords: aesthetics, colour, urban biodiversity, ecosystem services, restorative effects

Functional Forests - Urban Parks for mitigating and adapting to climate change in cities

Co-authors: Giuliano Maselli Locosselli; Maria de Fátima Andrade; Gabriel Costa Brito

Urban forests are one of the main tools available for the adaptation of cities to global climate change. However, there are still fundamental gaps to support decision-making in urban forests toward resilient cities. In this sense, this project assesses the ecosystem services provision of two parks in the city of São Paulo, namely: Ibirapuera Park (a central public park) and Fontes do Ipiranga State Park (one of the largest urban patches of the Atlantic Rainforest). We aimed at understanding the processes behind, and quantifying the ecosystem services provision, from both urban forests by using Eddy Covariance sensors that measure the fluxes of carbon dioxide, water vapor, and energy between the biosphere and atmosphere at high temporal resolution (10 Hz). The flux data is compared to micrometeorological observations on precipitation, air temperature and humidity, soil temperature and moisture content, and ecophysiological parameters measured at tree level in different native tree species. This comprehensive dataset spans from October 2022 to June 2023, with prospects for permanent measurements in both parks. The results show that these urban forests provide ecosystem services for the population, such as the promotion of carbon assimilation for urban mitigation, and climate regulation through the decrease in air temperature by the attenuation of surface sensible heat emission and increase in latent heat flow, as the evapotranspiration process of trees favors temperature reduction of the atmosphere. Thus, urban forests provide essential benefits to the population well-being, leveraging the resilience of cities in the face of climate change.

Terrestrial water storage and megacities hydric risks

Co-author: Giuliano Maselli Locosselli

The accelerated urban border growth over natural areas enlarges the exploitation of natural resources, generating biodiversity loss and climate change. Furthermore, the conurbation of overpopulated regions generates the emergence of megacities and megaregions. These areas occupy a vast territory with a high degree of waterproofing, which increases problems related to ecosystem services provision and climate regulation, in addition to generating risks of water crises for a large portion of the population. In Latin America, the Caribbean and North America, more than 80% of the population lives in urban environments, indicating that cities are experiencing growth and conurbation, affecting the hydrological cycle and rainfall regime on a global scale. However, despite precipitation playing an essential role in the hydrological cycle, recent studies demonstrate that ten-yearly precipitation trends do not necessarily determine the trends observed in terrestrial water storage, which largely depends on the distribution of vegetation cover. Since the growth of the urban network is associated with increased soil sealing, we are investigating the relationships between urban expansion and the risk of water security for populations and possible nature-based solutions for cities. In order to understand the impact of urban growth on water storage trends, we are utilizing remote sensing data obtained from various sources such as GRACE satellites, CHIRPS, ERA5, LANDSAT sensors, and GLDAS 2.2 reanalysis. The data collected from 1985 to the present helps us to obtain important information on climate, land use, and occupation. Our research indicates that the growth of urban networks has a negative impact on terrestrial water storage, which could potentially lead to water crises in megaregions. In order to mitigate this issue, we are exploring nature-based solutions and the possibility of incorporating green areas into cities to improve water management and minimize future water crises.

Navigating NBS Integration: Harnessing Urban Communities Vulnerability Mapping for Informed Prioritization, Insights from the NICHES Project in Barcelona, Boston and Rotterdam.

Co-authors: Eckelman M. J., Villalba Méndez G., Herreros-Cantis P., Langemeyer J.

In response to the mounting challenges posed by climate change, urbanization, and water-related hazards, this research project delves into the intricate dynamics of flooding and combined sewer overflows in urban areas. Emphasizing the vulnerability arising from environment injustice, high-intensity rainstorm events, limited combined sewer system capacities, and the prevalence of impervious surfaces, case studies from the Metropolitan Area of Barcelona, the City of Boston, and Rotterdam provide foundational insights. The NICHES project addresses these challenges by promoting nature-based solutions (NBS) tailored to urban vulnerabilities. This work emphasizes the urgency of integrating detailed vulnerability assessments with strategic NBS planning, aiming to bridge the gap between current urban water management approaches and the evolving demands of environmental resilience and societal well-being. NICHES establishes a comprehensive framework for considering climate-change-induced hydrological vulnerabilities, implementing NBS, gathering evidence, and offering guidance to decision-makers.

The research adopts a comprehensive Social-Ecological-Technological Systems (SETS) framework to unravel the interplay among distinct domains. Employing a novel approach that combines vulnerability and exposure factors, the study generates a spatially explicit score, providing nuanced insights into the impacts on urban communities resulting from hazards and future NBS planning. In light of the findings, the project emphasizes the imperative for nature-based solutions (NBS) and introduces a strategic framework for their prioritization in the urban environment. By fostering interdisciplinary research and adopting the SETS framework, cities can enhance their resilience against climate-induced water management challenges, paving the way for a sustainable and equitable urban future.

Urbanisation and Nature-based Solutions effects on biodiversity

Co-authors: Andre Rochelle, Karl Evans

Urbanisation creates intense pressure on ecological systems, reducing biodiversity and ecosystem service provision. This creates management difficulties given the intense demand for ecosystem services in cities given their high human population density. Nature Based Solutions (NBS) are increasingly proposed as a solution that can simultaneously enhance biodiversity and ecosystem services. NbS is gaining increasing policy and research attention. Consideration of ecosystem services and public acceptance dominates, whilst these factors are crucial, assessment of the biodiversity outcomes of NBS receives insufficient attention. We address this by considering how provision of NbS and habitats that mimic NbS alters urban biodiversity. We focus on well established habitats to avoid the risk of underestimating biodiversity benefits arising from lags in the colonisation of recently established NbS, and thus take an observation approach. Focusing on three large cities (Barcelona, Sao Paulo, Buenos Aires) we quantify the biodiversity gain arising from NbS provision relative to randomly selected points. Critically, we assess if the biodiversity gain delivered from NbS varies with position along the urbanisation gradient. We do so using random stratification to select survey locations along the urbanisation intensity gradient (measured using impervious surface) across each city. We focus on invertebrate biodiversity (species richness, abundance and biomass) responses to green fences (an NbS strategy designed to combat air pollution) and Sustainable Urban Drainage Systems (SuDS, designed to mitigate flood risk). Preliminary analyses indicate that across all locations and NbS systems biodiversity gain is greatest in more urbanised locations – having implications for the cost-effective allocation of NbS across cities. Our analyses, however, also indicate that the floral species composition of NbS like habitats is often limiting the realisation of biodiversity benefits. Our work has substantial implications for the design and deployment of NbS in urban locations in the Global North and South.

Nature-based solutions for Water Management: Analysis of the Andean context

Co-authors: Lucia Alexandra Popartan; Ignasi Rodriguez-Roda

Nature-based solutions (NbS) are globally implemented to address a wide variety of water management challenges. While extensive research on NbS has been conducted in the Global North, developing countries have received less attention. There is a lack of information about the NbS that can be applied in the Andean region and their potential to address water challenges and provide ecosystem services. This study aims to bridge this gap by performing a review of the emerging literature on NbS in the context of Andean countries. A comprehensive analysis of 38 publications was conducted, with a focus on strategies for addressing water-related challenges. Our findings reveal that there has been an increase in NbS publications in the Andean region in recent years. A higher prevalence of empirical studies was observed in grey literature. In addition, we identified 26 potential NbS, including ancestral practices, to address water challenges. The main challenges that Andean countries seek to solve through these NbS are water scarcity, flood risks, and water quality. This research highlights the significance of assessing the efficiency of NbS initiatives and disseminating this knowledge to discover more opportunities for implementation in the Andean region.