Sources of variation in microscopic epibiont communities on intertidal
rocky organisms in Niigata, Japan
Abstract
Microscopic epibionts are important components of an intertidal
ecosystem. However, because the epibionts are established on habitats
provided by basibiont (host) organisms, the epibionts are affected by
both the characteristics of basibionts and the environmental conditions
on the shore. Here, we hypothesized that variations in the epibiont
community were affected by the mobility, size, and surface roughness of
the basibiont organisms, and environmental conditions during a one-month
period in spring. Epibionts growing on 16 basibiont species belonging to
Gastropoda, Bivalvia, Polyplacophora and Echinoidea, as well as those
that had settled on plastic objects were collected from a rocky shore in
Niigata, Japan. Most epibionts collected were diatoms, and the highest
epibiont density was recorded on the surfaces of the limpet
Cellana toreuma. The epibiont community changed significantly
from April to May, and was also shaped by the characteristics of the
basibionts. The results indicated that basibionts with sessile, large,
or smooth surfaces had higher taxonomic richness, Simpson diversity, and
epibiont density than those with mobile, small, or rough surfaces.
Multivariate analysis of the epibiont community confirmed the importance
of these basibiont characteristics and the survey month. Six groups of
epibiont community were identified based on their contrasting sample
communities, and each had their own indicator species. The results
indicate that both environmental changes from April to May and changes
in basibiont species promote changes in the epibiont community in this
coastal region.