This communication aims to provide an overview of the outcomes and the
challenges encountered in using ciliated protists as indicator of ecosystem health in
the framework of several projects conducted in Italy since 2009. Ciliates (and, in
general, protistan microorganisms) in spite of the key roles they play in the microbial
loop, still constitute a neglected component of the biodiversity, which is rarely
included in ecological risk assessment plans. Ciliates are important bacterial and
fungal feeders and thus, they significantly contribute to channel nutrients up to the
food web. Furthermore, numerous ciliate species can be easily cultured with a short
generation time, such as those selected for the setting up of our ecotoxicological
experimentation (i.e., Coleps hirtus, Euplotes aediculatus, and Rigidohymena
tetracirrata). Thus, in this context, the present communication aims to highlight the
usefulness of ciliates as test organisms for the development of simple and costeffective
“prognostic” assays (i.e., able to detect sub-lethal toxicant effects of various
environmental matrices) based on the exploitation of antioxidant responses as well
as of “diagnostic” assays (i.e., able to detect overall ecosystem impairment) based
on the analysis of the community structures of ciliates in arable soils to evaluate the
potential impact of different agricultural managements
