Niche sharing and spatial distribution in intertidal decapods on the rocky shores of Easter Island

Abstract

Abstract The coastal marine ecosystems on Easter Island have been poorly studied, and the main studies were isolated species records based on the collections of scientific (primarily faunistic/floristic) expeditions. The aim of the present study was to apply a niche-sharing null model analysis on field observations of intertidal marine decapods on the rocky shores of Easter Island. The dominant species found were the decapods Planes minutus and Leptograpsus variegatus. The results of the null model analysis revealed that the species reported did not share an ecological niche, obviously corresponding to the absence of within-niche competition, and for P. minutus showed an aggregated pattern and negative binomial distribution, whereas L. variegatus had a uniform pattern and a binomial distribution. These results would agree with other, similar information about the littoral and sub-littoral fauna on Easter Island.