Effects of trampling on intertidal mussel beds: importance of disturbance intensity

MENDEZ, MM; LIVORE, JP; BIGATTI, G

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Año: 2018 vol. 606 p. 231 - 235

0171-8630

Trampling is one of the most frequent forms of human disturbance on rocky shores.This activity may directly reduce the abundance of dominant species, indirectly promote changesin the abundance of associated species and ultimately affect biological interactions. We assessedthe effects of different intensities of human trampling on Brachidontes spp. mussel beds, a dominantfeature on rocky intertidal flats of southwestern Atlantic coasts. We experimentally applied 6levels of trampling intensity on a Patagonian rocky shore. Simulated trampling intensity rangedfrom 0 to 600 tramples per day, and plots were disturbed replicating local usage patterns (i.e. australsummer weekend recreation). By the end of the experiment, Brachidontes spp. coveragedecreased as a result of increasing intensities of trampling and mostly replaced by bare rock. Eventhe lowest experimental intensity produced a loss of more than 40% of coverage. Changes incoverage were generally immediate and occurred after the first 2 trampling events, regardless ofdisturbance intensity. Our findings highlight that as few as 5 people walking on the mid-intertidalflat can produce a decline of the mussel bed cover in a specific area. Our findings also alert tothe urgency of implementing effective management actions in this and other frequented areasdominated by similar habitat-forming species