Public thesis defense Lucas Lerchs - LAB

Socio-Ecological Margins,Grounded struggles of everyday inhabitation in peripheral São Paulo

Friday June 26^th, 2026 - 4pm - Faculté d’architecture, d’ingénierie architecturale, d’urbanisme - Salle AV-02 - Rue Henri Wafelaerts 51, 1060 Saint-Gilles (Bruxelles) 

This doctoral research investigates the expanding self-help urbanisation of environmental reserves in peripheral São Paulo, which this study describes as socio-ecological margins. 

Situated at the intersection of housing exclusion and environmental crisis, this research questions how everyday inhabitation processes in São Paulo’s ecological reserve co-produced and are transformed by contemporary conditions of socio-ecological marginalisation. 

Grounded in four years of immersive fieldwork between 2022 and 2025 in three self-built communities —Comunidade KM47, Comunidade Linha do Trem, and Comunidade Terra de Deus— the research combines ethnographic cartographies, oral narratives, spatial documentation, and documentary filmmaking to build evidence of inhabitation struggles that often face erasure through eviction before being archived.

Building from latin american debates in critical urbanism, social geography and political ecology the thesis unfolds through three analytical lenses: everyday inhabitation practices, processes of (de/re)territorialisation, and grassroots governance. 

Across these lenses, the research develops three interrelated conceptual contributions. Under the lens of everyday inhabitation, the thesis conceptualises a marginalised environmentalism of subsistence as a conflicted form of environmentalism in which low-income families simultaneously protect and yet urbanise the ecologies they depend on, instrumentalising the natural environment as a transitional strategy toward urban citizenship. 

Under the territorial lens, this work discusses the concept of grounded relationalities to describe the fragile yet politically significant affective and symbolic bonds to territory produced through this inhabitation process which are systematically targeted and erased before they can be mobilised as collective resistance.
Lastly, through a governance lens, the study develops greyness as governance to expose the condition of legal indeterminacy and selective enforcement through which the State governs the socio-ecological margins, and which low-income populations and housing movements navigate as both a constraint and a survival resource.

Together, these three lenses expose how contemporary socio-ecological marginalisation operates by systematically targeting what this thesis calls the ecologies of the marginalised: the socio-environmental relations produced through cohabitation between low-income families and their biodiverse environments.
This study argues that material dispossession, legitimacy denial, and governance untranslatability collectively target and erode these ecologies, which are the precise terrain on which marginalisation is produced and through which resistance and more just socio-ecological futures remains possible.

Jury members

Prof. Chiara CAVALIERI (UCLouvain), Supervisor
Prof. Jeroen STEVENS (KULeuven), Supervisor
Prof. Gérald LEDENT (UCLouvain), Chairperson
Prof. Elisabetta CINZIA ROSA (UCLouvain), Secretary
Prof. Luciana NICOLAU FERRARA (Universidade Federal do ABC, Brazil)
Prof. Francisco DE ASSIS COMARU (Universidade Federal do ABC, Brazil)
Prof. Hanna HILBRANDT (University of Zurich, Switzerland)

Pay attention : the public defense of Lucas Lerchs will also take place in the form of a videoconference