Can short-term meteorological events alter subtropical estuarine macrobenthic assemblages in seagrass meadows (Patos Lagoon Estuary - Southern Brazil)?

Abstract

Short-term meteorological events, or occluded fronts, can cause variations in the diversity and density of macrozoobenthic assemblages from a seagrass meadow and sandflat at the subtropical Patos Lagoon Estuary (32 °S; Brazil). The first occluded front (EV1), with an average wind speed of 3.71 ms−1, did not disturb the macrofaunal assemblage because seagrass dampened the effect and increased the belowground biomass, seagrass coverage and canopy height. In contrast, after the second occluded front (EV2), with an average wind speed of 3.08 ms−1, the meteorological disturbance induced a reduction in vegetation coverage and epifaunal diversity in seagrass meadows. However, the EV2 disturbance increased the infaunal density in the sandflat and the diversity in the seagrass meadow. In this way, after EV2, the macrofaunal assemblages were modified in the sandflats. Our study shows the important role of shelter and habitat complexity provided by seagrass beds and highlights that, because of vegetation coverage loss, the occluded fronts, which are becoming more intense and frequent in a global warming context, can cause changes in macrofaunal assemblage structure.