| ------Arid ecosystems present
a two-phase mosaic structure of high and low cover patches. Vegetation patches
differ among ecosystems in size and shape. However, recent studies indicate
striking similarities in patch dynamics and in mechanisms explaining their
origin and maintenance. Two major types of systems characterized by the
shape of the patches, banded and spotted vegetation, both result from a
common mechanism although each is dominated by a different driver. Banded
vegetation occurs when water is the dominant driver of the redistribution
of materials and propagules, whereas spotted vegetation results when wind
is the major redistribution driver. Model analysis indicates that patchy
vegetation structure enhances primary production. |