  We use the context of dryland vegetation to study a general problem of
complex pattern forming systems - multiple pattern-forming instabilities that
are driven by distinct mechanisms but share the same spectral properties. We
find that the co-occurrence of such instabilities results in the growth of a
single mode rather than two interacting modes. The interplay between the two
mechanisms, which promote or counteract each other, compensates for the simpler
dynamics of a single mode by inducing higher pattern diversity. Possible
implications to biodiversity of ecosystems are discussed.
