Mapping plant-microbe symbiosis across spatial scales

Soils are among Earth’s most biodiverse yet least explored ecosystems. Microbes that live in symbiosis with plants are essential for nutrient cycling, productivity, and carbon storage, yet remain difficult to map because they operate across many spatial scales. This thesis examines how plant associated microbes are distributed from individual roots to global patterns. I combined artificial intelligence, robotic imaging, DNA sequencing, field campaigns, and greenhouse experiments to describe variation in microbial diversity and biomass. The results show that different drivers dominate at different scales. Local variation is largely shaped by plant traits and soil conditions, while at the global scale patterns emerge from climate and land use gradients. Together these findings improve our ability to understand soil life and supports better management of microbes for sustainable agriculture, carbon drawdown, and biodiversity conservation.