  Short-scale interactions yield large-scale vegetation patterns that, in turn,
shape ecosystem function across landscapes. Fairy circles, which are circular
patches bare of vegetation within otherwise continuous landscapes, are
characteristic features of semiarid grasslands. We report the occurrence of
submarine fairy circle seascapes in seagrass meadows and propose a simple model
that reproduces the diversity of seascapes observed in these ecosystems as
emerging from plant interactions within the meadow. These seascapes include two
extreme cases, a continuous meadow and a bare landscape, along with
intermediate states that range from the occurrence of persistent but isolated
fairy circles, or solitons, to seascapes with multiple fairy circles, banded
vegetation, and "leopard skin" patterns consisting of bare seascapes patterns
consisting of bare seascapes dotted with plant patches. The model predicts that
these intermediate seascapes extending across kilometers emerge as a
consequence of local demographic imbalances along with facilitative and
competitive interactions among the plants with a characteristic spatial scale
of 20 to 30 m, consistent with known drivers of seagrass performance. The
model, which can be extended to clonal growth plants in other landscapes
showing fairy rings, reveals that the different seascapes observed hold
diagnostic power as to the proximity of seagrass meadows to extinction points
that can be used to identify ecosystems at risks.
