Joshua studies how cities and other human-dominated landscapes emerge and are transformed through linked socio-political and ecological processes. His field work is based in New Orleans and the lower Mississippi River Delta, where before joining the Resilience Centre, he was a Research Analyst at Tulane University. Joshua's previous work in New Orleans documents the political struggles and ecological ramifications of flood control and coastal restoration projects that have been planned and/or implemented since the region was devastated by extensive infrastructure failures during Hurricane Katrina in 2005 and the BP oil disaster of 2010. Joshua's PhD work is one component in the FORMAS funded project entitled "Socio-ecological Movements in Urban Ecosystems," which brings together scholars in urban ecology and social movement studies to critically study issues of urban natural resource management in New Orleans, USA, and Cape Town, South Africa. The project aims to link the study of collective action as it has been conceived and studied by social movement scholars, with biophysical studies of urban ecology. Striving to understand how collective action can be viewed as not only producing cultural, social or political changes, but also biophysical or ecological changes. The study compares how civic organizations in Cape Town and New Orleans, two port-cities with a long history of systematic apartheid and racial segregation, have produced both cultural and political changes, and ecological changes.
The project uses quantitative methods like social network analysis (SNA) and biophysical assessment methods, as well as more qualitative and historical ones. It strives to combine ecological and social sciences to critically engage and influence the discourse on social-ecological systems and resilience.