2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/167965Self-arrangement of individuals into spatial patterns often accompanies and promotes species diversity in ecological systems. Here, we investigate pattern formation arising from cyclic dominance of three species, operating near a bifurcation point. In its vicinity, an Eckhaus instability occurs, leading to convectively unstable "blurred" patterns. At the bifurcation point, stochastic effects dominate and induce counterintuitive effects on diversity: Large patterns, emerging for medium values of individuals' mobility, lead to rapid species extinction, while small patterns (low mobility) promote diversity, and high mobilities render spatial structures irrelevant. We provide a quantitative analysis of these phenomena, employing a complex Ginzburg-Landau equation.4 pages, 3 figures and supplementary information. To appear in Phys. Rev. Lett.Populations and EvolutionStatistical MechanicsAdaptation and Self-Organizing SystemsBiological Physicstext