The variability in genera composition (β-diversity) differed significantly according to lagoon typology and location (Table 4). Total β-diversity was significantly higher in closed lagoons, intermediate in ICOLLs and lower in the open lagoons (Fig 6 and S7 Table). Significant variations in β-diversity among lagoons within individual typology were mainly detected in closed ones (S8 Table). At the scale of locations within the lagoon, the genera variability was lower than at the scale of lagoon. Total genera variability between locations varied significantly in open lagoons and ICOLLs, but not in closed ones (S9 Table). The relative contributions of replacement and richness components to the nematode genera variability also differed significantly among lagoon typologies, with and increasing dominance of replacement over richness as lagoon connectivity increased (Fig 6).