AN ANALYSIS OF SURFACE ACTIVITY OF BEACH RESIDENT INVERTEBRATE COMMUNITY DURING STORM EVENTS

Abstract

Increasing storminess is among the expected effects of climate change; systems such as sandy beaches –and especially those on islands- are particularly exposed to these events. Data related to behavioural reactions of resident beach fauna to storms could hence provide useful insights for the study of beaches’ resilience. A study was carried out on two beach units on the NE coast of Crete island (Greece), seasonally subjected to violent storms. Daily surface activity of resident fauna was analysed through temporal replicates (four different moon phases) during the months of March and April 2016. Pitfalls were placed along transects perpendicular to the shoreline and emptied every three hours, with spatial replicates on the two units. A wind storm hit the coast during the third replicate, so a control was carried out in occurrence of the same moon phase in the next month. Data indicate nocturnal peaks of activity for resident fauna, dominated in abundance by amphipods and beetles, Talitrus saltator, Deshayesorchestia deshayesi, Phaleria bimaculata (in decreasing density order). Neither the storm nor the high variability recorded across replicates in terms of: wind speed, beach face slope, substrate temperature, stranded wrack presence seemed to reduce surface activity, or to shift it. A local adaptation to environmental conditions seems therefore to be in place.