-The interdisciplinary study on the “ecology of segregation” included Olga Barbosa, Associate Director of the Institute of Ecology and Biodiversity (IEB) and professor at Universidad Andrés Bello.
Segregation is a multidimensional phenomenon deeply intertwined with historical, social, and ecological contexts. Yet this more integrated perspective has received limited attention in the Global South. A recent study focusing on the city of Valdivia offers an exception, examining three key historical moments: colonization, the devastating 1960 earthquake, and current struggles to protect urban wetlands.
The research, published in the prestigious scientific journal PNAS , was carried out by an interdisciplinary team of researchers from Chile and abroad specializing in ecology, hydrology, and anthropology, in collaboration with a broad network of public-sector and civil society stakeholders, including the municipality, SENAPRED, Chile’s Ministry of Public Works (MOP), and civil society organizations.
The study was co-led by Elizabeth M. Cook of the Cary Institute for Ecosystem Studies and Olga Barbosa, Associate Director of the Institute of Ecology and Biodiversity (IEB) and professor at Universidad Andrés Bello, together with Jason Sauer of the Oregon Department of Energy and Karin Weil of Chile’s National Cultural Heritage Service.
Using the concept of the Ecology of Segregation , the researchers explored how socioecological dynamics—including socioeconomic inequality, structural racism, and colonial legacies—shape the urban environment and, in turn, are shaped by it. Their findings show that current patterns of segregation are the result of complex, multidimensional processes that differ in important ways from those more commonly described.
The analysis also considered the displacement of Indigenous Mapuche communities during the conquest, the spatial restructuring and uncontrolled urban development that followed the 1960 earthquake, and urban expansion and wetland occupation influenced by governance shaped by neoliberal economic policies.
Olga Barbosa, a professor at Universidad Andrés Bello, explains that the study grew out of a collaboration examining how climate change and global change more broadly are shaping cities and affecting both biodiversity and people. The publication also draws on previous research conducted by the scientist, including work mapping Valdivia and modeling what the city looked like before and after the earthquake. That research found, for example, that many areas providing substantial ecosystem services to the population were not formally designated as green spaces, despite functioning as such, as they included fragments of wetlands and other landscapes.
“In this recent work, which highlights the value of natural and social capital simultaneously, we wanted to discuss what happens with segregation in cities from an ecological perspective and in the context of Latin America. Through this study, we sought to bring forward questions related to environmental and socioeconomic justice. Ultimately, what we wanted to explain is that the segregation we see today also creates inequitable access to nature and its ecosystem services, and that it is multifactorial, involving historical, geological, and political processes,” says the researcher.
Three key moments in Valdivia
According to the study’s authors, Valdivia, the capital of the Los Ríos Region in southern Chile, has a unique sociocultural and ecological history. With a population of approximately 166,000, the city lies within the Valdivian temperate rainforest biodiversity hotspot, an area characterized by high species richness and endemism. The city also depends heavily on surrounding native forests for its drinking water supply.
Valdivia is located at the confluence of rivers and extensive wetlands, which create natural barriers to urban development, alongside forestry and agricultural areas and well-preserved native forests.
The first milestone examined in the study is European colonization between 1552 and 1820. To investigate this period, the researchers used maps of Valdivia produced by the Dutch, who briefly occupied the city in the 17th century. Since its refounding by Spanish conquerors, Valdivia was the site of territorial dispossession of Mapuche communities.
These Indigenous populations maintained close relationships with the land, wetlands, and rivers, but were displaced from fertile territory. Today, some of those same areas are occupied by high-income neighborhoods with privileged access to green spaces and ecosystem services, including flood mitigation.
The Spanish did not fully displace the Mapuche until 1643, following a brief Dutch colonization attempt. In the book Nueva Historia de Valdivia ( New History of Valdivia ), chroniclers of the period referred to the environmental benefits of the landscape, including its shallow lagoons and wetlands, the navigability of the river, and its proximity to the sea. They described Valdivia as an “ecological nest” in the Coastal Range, between the ocean and freshwater systems, and as a major commercial hub where products from both the Andes and the coastal area of Corral converged.
A second key moment was the 1960 earthquake . On May 22, 1960, a magnitude 9.5 earthquake—the largest ever instrumentally recorded—struck along a 1,000-kilometer stretch, severely affecting the Valdivia area. The earthquake lasted 10 minutes and was followed an hour later by a tsunami with waves reaching up to 20 meters in height, as well as weeks of aftershocks.
The tragic event caused devastating loss of life and severe damage to built infrastructure. It also triggered extensive land subsidence and massive flooding associated with the tsunami. These events drastically transformed Valdivia’s landscape, leading to the rapid formation of a new network of wetlands throughout the area. The rivers surrounding Valdivia also deepened, and shallow banks formed, contributing to this new and persistent wetland network.
The 1960 earthquake thus triggered a reconstruction process oriented toward resilience, but one that ultimately further consolidated and institutionalized patterns of segregation in Valdivia through the neoliberal policies of the 1980s.
“What this winter is showing us in Valdivia is not an isolated event, but rather the same logic we describe in the study: there has been sustained pressure from an urbanization model that occupied wetlands for decades, and extreme events, such as these record rains, act in a similar way to the 1960 earthquake—they make an existing inequality visible and worsen it. The areas that flood most today often coincide with lower-income neighborhoods, which are precisely those located at lower elevations following the reconstruction of the 1960s,” explains Olga Barbosa.
A third crucial moment highlighted by the research is the current struggle to protect wetlands . In recent decades, local communities, scientists, and social organizations have mobilized to protect urban wetlands from real estate expansion and government neglect.
This collective effort helped drive the creation of Chile’s Law No. 21,202 on the Protection of Urban Wetlands. Although the law initially had gaps, these were addressed in 2021 as a result of social and scientific pressure, requiring environmental assessments for projects that could affect these ecosystems.
Looking ahead
Valdivia is not an isolated case. Many cities in the Global South share similar histories. For this reason, the study argues that understanding the ecology of segregation in different urban areas can help us imagine and build cities that are fairer, more resilient, and more respectful of their natural and cultural heritage.
In this context, the PNAS study notes that, as in many urban areas, patterns of segregation and the unequal distribution of environmental goods and resources have been documented throughout Latin America. In general, proximity to and access to green spaces in the region tend to reflect higher socioeconomic status.
“In Valdivia, higher-income neighborhoods have formal green spaces, but these account for a very small percentage of the city’s total green space. At the same time, spontaneous, informal green spaces, such as wetland fragments, have greater biodiversity and provide more ecosystem services, and these are precisely the areas located in lower-income neighborhoods,” explains Olga Barbosa.
“This winter’s flooding is an urgent reminder of why protecting urban wetlands is not only a matter of biodiversity, but also of environmental justice: wetlands buffer floodwaters and absorb excess water. When we fill them in or leave them out of urban planning, we remove protection from precisely those neighborhoods that already have fewer resources to cope with an emergency,” says the researcher.
Despite this, much of the theoretical and empirical research on the Ecology of Segregation has been conducted in the United States, and the topic remains understudied in the Global South. Studies such as this one can therefore have important implications for understanding the current dynamics and future trajectories of environmental justice in the region, helping to develop public policies better suited to local territories while taking advantage of the opportunities provided by nature.
Drawing on the example of Valdivia, the authors also suggest that these findings can inform more inclusive urban planning and policies that incorporate community-based approaches and recognize Indigenous perspectives, helping to mitigate deeply rooted inequalities and promote sustainable development.
“It is important to consider that with good urban planning, we could absorb, counteract, and mitigate socioeconomic injustice. By protecting and formally recognizing informal green spaces, we would be providing many ecosystem services to people with fewer resources. That is the foundation of the proposal,” Barbosa emphasizes.
The experience of Valdivia shows how natural disasters, political decisions, and historical legacies of inequality are intertwined with the natural environment. It also reveals the potential of collective action, inclusive planning, and interdisciplinary knowledge to advance toward greater environmental equity.
Proceedings of the National Academy of Sciences
Case study
Not applicable
Multiple drivers and long-term patterns of the ecology of segregation in Latin America
14-Sep-2026
The authors declare no competing interests