Meiofauna are presently regarded as very suitable organisms to monitor potential
ecological effects of natural and anthropogenic disturbances in aquatic ecosystems. The presence of the non-indigenous bivalve R. philippinarum in the Tagus estuary
presented the opportunity to evaluate the ability of meiofauna communities,
specifically nematodes, as indicators to assess disturbances promoted by an
allochthonous species.
This research focused on the benthic meiofauna assemblages response to the presence
of a non-indigenous bivalve. Density, diversity and trophic composition patterns of the
meiofauna communities, particularly nematodes were examined along the estuary
gradient and related to environmental conditions and the occurrence of R.
philippinarum. All the performed analysis showed that nematodes density, distribution
patterns, diversity and trophic composition were mainly structured by distinct
environmental factors like sediment grain size and salinity rather than by R.
philippinarum densities.