Where to start? – The interplay of what, who and where in phase-0 of transdisciplinary research

Transdisciplinary research (TDR) is increasingly recognized as an important approach to make research on complex environmental and sustainability issues such as climate risks and biodiversity loss more societally relevant and actionable. Deliberately designing early stages of TDR– phase-0 – is considered essential to its overall success. However, limited knowledge is available about how to shape and undertake phase-0 of TDR. We provide a detailed account of TDR processes in the WildlifeNL project, which were designed with explicit and extensive attention to phase-0. We saw that designing and shaping the project was a constant process of decision-making about delineation; defining consortium composition and participation of others outside the consortium (‘who’), selecting cases and sites (‘where’), and determining model systems, questions, and approaches (‘what’). We demonstrate the interwovenness and interdependency between these dimensions based on several examples from WildlifeNL. The WildlifeNL team primarily focused on diverse stakeholder representation and building on existing partnerships. They thereby prioritized the ‘who’ dimension, while leaving ‘what’ and ‘where’ more flexible to adapt. The interconnectedness and interdependency confront those designing and implementing TDR with the question how to balance and prioritize the different dimensions, which defines how they make decisions on who, where and what are included and excluded in their TDR. We advocate for reflection and transparency about these messy and power-laden processes and suggest our framework as a structure for doing this. We argue that different TDR objectives and impact orientations (‘why’) may also prompt assigning different relative weight to the ‘who’, ‘where’ and ‘what’ dimensions. • We analyzed phase-0 of the transdisciplinary research project WildlifeNL, which examines human-wildlife coexistence. • Phase-0 is a dynamic and non-linear process of delineating the ‘what’, ‘who’ and ‘where’ of transdisciplinary research. • WildlifeNL prioritized the ‘who’ dimension to favor diversity and trust in support of the project’s transformative ambition. • We argue that different impact orientations of transdisciplinary research may prompt different delineation priorities. • We advocate for more transparency about the messy and power-laden phase-0 of transdisciplinary research projects.