Is an ecosystem perspective sufficient to understand meta-ecosystem processes? A critical reflection

Meta-ecosystems are the largest and probably most complex structures investigated in ecology. Because of their complexity, they are often separated into their respective sub-systems and then studied in isolation. This is often done without analysing whether an understanding of the individual ecosystems can lead to a proper understanding of the meta-ecosystem, likely because we lack clear guidelines as to when such a separation is sufficient. In the accompanying study (DOI: 10.1002/oik.11127), we propose four conceptual models for which a separation may approximate the full dynamics. For one of those methods, we provide a new theoretical framework to assess how strongly two ecosystems are linked and test this new method on virtual data. We show that the new method is a good approximation of the coupling strength between two ecosystems. Here we provide the computer code to compute this method.