The primary difference between small, controlled lab experiments and ecosystem-scale experiments is the applicability of the results.
Small lab experiments tend to focus on specific variables in a controlled setting, which can limit how the findings relate to real-world scenarios. In contrast, ecosystem-scale experiments consider a broader range of interactions and abiotic factors, making their results more applicable to natural systems.
While other options like abiotic factors, species of interest, and the number of variables may vary as well, the key distinction often lies in how the results can be generalized to larger ecological contexts.