MEPS 530:15-27 (2015)  -  DOI: https://doi.org/10.3354/meps11337

ABSTRACT: Biological traits relating to the behaviour, morphology and life history of organisms can influence ecological functioning, and this principle is becoming increasingly used to examine the functional response of communities to environmental variation. We quantified the taxonomic and biological traits composition, and the overall abundance and richness, of small (1-8 mm) mobile invertebrate assemblages inhabiting subtidal coralline algal turf (Corallina officinalis) along an environmental gradient ranging from (1) relatively deep, wave-exposed sites with short turf containing a low proportion of fine sediment to (2) shallow wave-sheltered sites with taller turf containing a higher proportion of fine sediment. Turf fauna were diverse (118 taxa) and abundant (12000-53000 ind. m^-2), with assemblages dominated by amphipods and gastropods. Total abundances of invertebrates were higher at the wave-exposed sites. When analysed in multivariate space using proportional abundance, replicates based on taxonomic composition grouped more strongly by site along the overall gradient than those based on traits. As proportions of biological traits remained relatively stable along the gradient, numbers of all traits possessed by individuals were higher at the wave-exposed end of the gradient. Although some environmental variables contributed significantly to explaining multivariate trait and taxa patterns, most individual correlations between environmental variables and traits and taxa were weak. This study shows that biological traits can be shared between taxonomically distinct assemblages of turf-dwelling invertebrates, and indicates a relatively small influence overall of environmental variables on the composition of traits and taxa.

KEY WORDS: Temperate rocky reef · Diversity · Algal morphology