Do different sympatric seagrasses support macrobenthic faunas of differing composition, abundance, biodiversity or patchiness?

Abstract

Intertidal macrobenthic assemblages associated with monospecific areas of different sympatric though not syntopic seagrasses [Cymodocea, Halodule, Zostera and Halophila] were investigated in Moreton Bay across a continuous <0.12 ha seagrass area with minimal potentially-confounding environmental variables. Results indicated patterns of unchanging faunal metrics across seagrass types (abundance, richness, diversity, evenness, taxonomic distinctness, and patchiness) but variation in relative proportions of dominant taxa, particularly microgastropods (abundant in Zostera, insignificant in Cymodocea and Halodule). Although assemblage composition varied, faunal dissimilarities (except with Zostera) were very low and of similar magnitudes within and between different 'host' seagrasses. This suggests that such macroecological faunal characteristics are not consequent on the precise local ecosystem engineer but largely reflect those of a common pool of locally available species, so that the differences in animal abundance and biodiversity described in some studies relate not directly to features inherent in the different seagrasses, but to associated habitat variables.

Keywords: Intertidal; Macrobenthic abundance; Macrobenthic biodiversity; Macrobenthic composition; Macrobenthic patchiness; Moreton bay; Seagrass; Sympatry.