Changes to the structure of tropical seagrass meadows (Halophila decipiens) in the warm-temperate waters of the southwest Atlantic

Abstract

Keystone species are on the move globally and understanding how these new arrivals integrate into their new environments will become increasingly important. We monitored the development of range-expanded seagrass meadows (Halophila decipiens) in the warm temperate waters of the São Sebastião channel (SSC), Brazil. Following its first description in the summer of 2014, the meadows formed by this species have increased in terms of average patch size (3.6 × greater), biomass (3.8 × greater and 4.6 × greater, respectively for above and below ground biomass) and have been associated with increases in sediment organic carbon (Corg) stocks (2.6 × greater). We conclude that this traditionally pan-tropical species will play an increasingly important role in the structure (e.g., providing habitat for fauna), productivity (e.g., food resources) and carbon storage potential of shallow coastal waters in the southwest Atlantic.