Original ArticlesHuman-induced changes in the trophic functioning of sandy beaches

- Human impact on food web and energy flow was evaluated on tropical sandy beaches.
- Mass-balanced models were applied on dissipative and intermediate sandy beaches.
- Human impact impairs the energy flow through trophic levels.
- The negative effects of tourism occur regardless of beach morphodynamics.
- Biomass reduction of macroinvertebrates may affect coastal energy exportation.

The increasing anthropogenic disturbance on coastal ecosystems has threatened ecological interactions and ecosystems functioning. To investigate if human pressure affects the trophic structure of sandy beaches, mass-balanced models were applied on two Brazilian sandy beaches with distinct human impact degree. The food web models included detritus, phytoplankton, macroinvertebrates, fish and seabirds. Macroinvertebrates in non-urbanized sectors represented the highest production fraction consumed by predators. The energy transfer and the cycling indicator were more efficient in the non-urbanized sectors than urbanized ones. The results indicate that macroinvertebrates sensitive to direct human impact such as trampling are important to the trophic functioning of sandy beaches. Establishing a threshold for the number of beachgoers or dispersing recreational activities to avoid crowds may be tangible ways to mitigate the trampling impact on macroinvertebrates.