A general meta-ecosystem model to predict ecosystem functions at
landscape extents
Abstract
The integration of ecosystem processes over large spatial extents is
critical to predicting whether and how global changes may impact
biodiversity and ecosystem functions. Yet, there remains an important
gap in meta-ecosystem models to predict multiple functions (e.g., carbon
sequestration, elemental cycling, trophic efficiency) across ecosystem
types (e.g., terrestrial-aquatic, benthic-pelagic). We derive a flexible
meta-ecosystem model to predict ecosystem functions at landscape extents
by integrating the spatial dimension of natural systems as spatial
networks of different habitat types connected by cross-ecosystem flows
of materials and organisms. We partition the physical connectedness of
ecosystems from the spatial flow rates of materials and organisms,
allowing the representation of all types of connectivity across
ecosystem boundaries as well as the interaction(s) between them. Through
simulating a forest-lake-stream meta-ecosystem, our model illustrated
that even if spatial flows induced significant local losses of
nutrients, differences in local ecosystem efficiencies could lead to
increased secondary production at regional scale. This emergent result,
which we dub the ‘cross-ecosystem efficiency hypothesis’, emphasizes the
importance of integrating ecosystem diversity and complementarity in
meta-ecosystem models to generate empirically testable hypotheses for
ecosystem functions.