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.