Elevated habitat quality reduces variance in fish community composition

► Expectations of density dependence were evaluated with a nearshore fish community. ► Eelgrass (good) and unvegetated (poor) habitats were analyzed (1996-2009). ► In line with theory, variability in community composition was less in good habitat. ► Communities in poor habitat had more pronounced directional change across years. ► Community composition in suboptimal or degraded habitats is less predictable.