Colonisation patterns of supralittoral arthropods in naturally stranded wrack debris on Atlantic sandy beaches of Brazil and Spain

Research Projects
Organizational Units
Journal Issue
From an ecosystem perspective, wrack debris represents a key element for the maintenance of biodiversity and functioning of sandy beaches. Here, we characterised the colonisation patterns of supralittoral assemblages associated with wrack accumulations (seaweed and mangrove propagules) on multiple Atlantic sandy beaches (southern Brazil and south-western Spain). By using a manipulative field experiment, we sought to determine the temporal changes of the density, diversity and the structure of the whole community during the colonisation of wrack debris, and whether the colonisation patterns in response to the stranding of natural wrack debris were different on local (between beaches) and regional (between Atlantic regions) scales. Our results showed increases in density and diversity during the first 3 days after the stranding of seaweeds and mangrove-propagules debris. Moreover, wrack debris was promptly invaded by a wide range of species (i.e. talitrids, dipterans, coleopterans and spiders), although the colonisation pattern was slower in southern Brazil (16-day period) than in south-western Spain (3-day period). Wrack-debris characteristics (e.g. amount, degradation and composition) combined with biological strategies (e.g. trophic guilds and mobility) of supralittoral species could explain the different colonisation patterns in each Atlantic region. The temporal changes of wrack-associated fauna can have potential effects on the wrack-derived process and food-web structure on sandy beaches.
UCM subjects