Halting biodiversity decline and ensuring food security are urgent and interconnected challenges. I will study how social and ecological structures in interaction generate tradeoffs and synergies between food security and biodiversity conservation. SENet has two aims: A) to identify ecological and socioeconomic structures that benefit or harm food security and biodiversity conservation in a rural, poor study landscape, and B) to develop an integrated network model capable of predicting such effects in similar settings worldwide. Globally, SENet will be the first research to apply (graph-theoretic) network analysis to understand synergies and tradeoffs in the food security–biodiversity nexus. I will develop the integrated model using data from a landscape in Ethiopia, where agricultural expansion and human-wildlife conflicts are driving deforestation. SENet differs from existing approaches that concentrate on increasing agricultural output and overlook that social and ecological outcomes are interdependent and cannot be understood separately. In contrast, my method focuses on the food security of rural villages and on the factors that prompt farmers to clear or to plant forest, to change crops, to migrate elsewhere, etc., i.e., on farmers' decisions that affect both food security and biodiversity. In this context, I will use systematic network analysis to show how farmers are connected through food trade, knowledge exchange and other socioeconomic processes, but also how their crop fields are linked to forests and human–wildlife conflicts. The implementation of SENet will draw on my skills in network analysis and the host’s research excellence on the biodiversity of agricultural landscapes, including their ongoing fieldwork in my study area. This setup ensures a theoretical and empirical foundation for my network models, and a forum for communicating my results to non-academic actors in Ethiopia and Europe.

Sustainability science is an innovative research field dealing with complex socio-ecological problems of our time, from climate change and rapid urbanization to pandemics and loss of biodiversity. A major goal for sustainability science is to support societal transformations towards sustainability by generating, testing, and integrating (1) system knowledge about sustainability problems, (2) target knowledge about desirable futures, and (3) transformational knowledge about effective interventions that can lead from the problems detected to the desirable futures. Thus far, epistemological work has focused primarily on the foundations of system and target knowledge and has neglected transformational knowledge. Therefore, a major task for an epistemology of sustainability science is now to understand how transformational knowledge is generated and tested. Because of the central role they play in transformational sustainability science, in EPISUS, I take transformational experiments as entrance point to develop an epistemology of transformational sustainability science. I ask: What kind of sustainability science do we need to generate and test transformational knowledge and what role can transformational experiments play in this science? In EPISUS, I address this question by focusing on: 1. the main characteristics of transformational experiments, 2. the criteria used to evaluate experimental results and 3. the kind of theories that support, or could support, the production of transformational knowledge. I use a research design that combines the investigation of concrete examples of transformational experiments and conceptual reflections using analytical tools from the philosophy of science. EPISUS will provide a new conceptualization of transformational experiments as well as categories for the further development of transformational approaches in sustainability science that are theoretically sound and evidence-based.

Mainstreaming Social-Ecological Sufficiency: Closing the sustainable consumption gap between societal demand and ecological limits Global patterns of production and consumption are fundamentally unsustainable, threatening key planetary boundaries—earth system processes vital for maintaining of ecological integrity and human well-being. Strategies for averting this ‘ecological overshoot’ have largely focused on ‘greening’ production by reducing the material intensity (efficiency), or the material throughput (consistency) of economic activity. However, neither of these approaches address what constitutes a sustainable scale of economic activity. Here, the novel notion of social-ecological sufficiency—a socially satisfactory standard of living within ecologically sustainable natural resource usage—represents a vital third (integrative) strategy for moving towards an economy within a 'safe operating space for humanity’. The overall aim of MaSES is to mainstream the notion of social-ecological sufficiency as a conceptual and empirical bridge between research on planetary boundaries and sustainable production and consumption, with far-reaching academic and societal implications for sustainable resource use. WP1 will synthesize disparate approaches to conceptualizing sufficiency and cement social-ecological sufficiency as a core idea in sustainability. WP2 will employ a global environmentally extended material and energy flow analysis to quantify key planetary boundaries (land-system change, biochemical flows, climate change and freshwater use) in terms of ‘ecologically sufficient’ levels of household consumption. WP3 will adapt methods from consensual deprivation assessments to identify ‘socially sufficient’ levels of household consumption across different social groups. WP4 will assess the feasibility of different strategies for closing the gap between ecologically ‘safe’ and socially ‘acceptable’ levels of household consumption. WP5 addresses project management.