LAUSR

Abstract Saltmarshes are coastal plant formations frequently found associated with tropical and subtropical mangroves. Saltmarshes in these regions are subject to a wide array of environmental factors. This vegetation has direct and indirect effects on benthic fauna structure both above and below sediment surface. This study describes the vertical distribution of macrobenthic fauna in Amazon saltmarshes with different sediment characteristics. Four vertical stratified samples (0–10 and 10–20 cm) were collected at two different sites: (1) Furo Grande tidal channel (muddy area) and (2) Ajuruteua beach (sandy area). The saltmarsh area varied between sites, being more dense and taller in the sandy area. A total of 1959 individuals were found, belonging to 35 macrobenthic taxa, of which 23 taxa are exclusive to the muddy area. Macrobenthic fauna community distribution varies among Spartina alterniflora marshes with different sediment characteristics. Higher densities and number of taxa were generally found at near-surface layers (0–10 cm). Furthermore, this vertical distribution occurs differently depending on the site and is more prominent in sandy areas where all fauna is concentrated near the surface.