Regular patterns of vegetation have been observed in many arid and semiarid ecosystems worldwide, covering a diverse range of plant taxa and soil types. The study of such patterns is especially interesting because their features may reveal much about the underlying physical and biological processes that generated them, in addition to giving information on the characteristics of the ecosystems. Finally, the beauty of its shapes, observed using aerial photography, has contributed to draw the attention of many scientist.
Theoretical work trying to explain the formation of these structures has traditionally focused on the interaction among plants and also between the system and external factors. In the first line, one of the most accepted ideas suggests that scale-dependent feedback (interactions promoting and avoiding plant growth acting at different scales) could be responsible of a symmetry-breaking instability of the homogeneous state and therefore of the formation of vegetation patterns. In this seminar, we will review this concept and present recent results showing that vegetation patterns still appear if only competitive interactions come into play.