M. Torrisi

BIOLOGICAL MONITORING OF SOME APENNINE RIVERS (CENTRAL ITALY) USING THE DIATOM-BASED EUTROPHICATION / POLLUTION INDEX (EPI-D) COMPARED TO OTHER EUROPEAN DIATOM INDICES

The EPI—D diatom index was used in monitoring seven rivers situated in the central-eastern Apennine sector (Italy) in agreement with the European Directive, WFD/60/2000/EC, which encourages all member states to use available instruments in order to assess the ecological status of rivers, including algae. This index is based, above all, on the high sensitivity of diatoms to organic matter, nutrients and mineral salts dissolved in water, particularly chlorides. A total of 148 samples were examined and 209 diatom taxa were identified to the species and varieties level. The 100 species most representative of the studied watercourses typology were chosen and subjected to cluster analysis, in order to determine more information about their ecological requirements. Moreover, a comparison between the results obtained by the EPI-D and other European diatom indices was made and it indicated a very high correlation between them. The EPI-D index when compared with the chemical data and the general situation of the examined watercourses showed an excellent capacity for synthesis; therefore it can represent a useful instrument for ecological assessment of Italian rivers.

The Eutrophication/Pollution Index-Diatom based (EPI-D) and three new related indices for monitoring rivers: The case study of the river Potenza (the Marches, Italy)

Abstract The aim of this study was to test three new partial indices correlated to the already known eutrophication/pollution index-diatom global index, all based on diatoms, for assessing the biological quality of the river Potenza. This is an Apennine watercourse that crosses the Marches region and enters the Adriatic Sea. This research complies with the WFD/60/2000/EC, which imposes the combined use of biotic and abiotic aspects in evaluating the ecological status of surface waters. The three partial indices express the sensitivity of diatoms to nutrients (TI-D), organic matter (SI-D), and mineral salts (HI-D). In 13 stations selected along the main watercourse, a total of 133 diatom taxa were found. The results obtained by applying the above-mentioned indices to the diatom communities are expressed numerically on a scale of 1 to 20, where the high values mean good or excellent quality and the low values mean bad quality. All the indices employed showed inverse high correlation with the chemical parameters responsible for organic and mineral pollution and eutrophication, which increase progressively downstream. These indices performed very well in monitoring the river Potenza and showed excellent positive correlation with other diatom indices widely used in Europe.

Influence of urbanization on riparian and algal species composition in two rivers of central Italy

Abstract The riparian flora and algal (diatom) communities in the urban stretches of the Tronto River and its tributary, the Castellano, were studied where they flow through the city of Ascoli Piceno (central Italy) in order to correlate their composition to human disturbance. The research revealed notable dynamic exchanges between the city and its rivers and revealed a vegetation mosaic of heterogeneous origin, rich in ornamental trees and shrubs, as well as nitrophilous and cultivated entities. urbanization tends to select plants with broad ecological range and wide distribution, thus causing the cosmopolitization of the riparian flora; the area studied hosts an abundance of cosmopolite species. A developed shrub layer here fosters the presence of a rich avifauna. Diatoms and hydrophytic—helophytic plants indicate excellent to good water quality in the Castellano River and only passable water quality in the Tronto. These results suggest that examination of both riparian and diatom species composition provides more precision in assessing the quality of river habitats subjected to human-induced alterations, especially in moderately extended and highly disturbed stretches, thus facilitating ecologically correct restoration projects.

Rheophile Apennine Diatoms and Their Use as Bioindicators of Water Quality

A brief survey of the diatoms found up to now (about 450 taxa) in the watercourses of the Apennines, an imposing mountain chain extending along the Italian peninsula, was made. A particular attention was given to the ecology of these diatoms. As the pH and oxygen are concerned, the alkaliphile and oxyphile forms dominate sharply. In the saprobic spectrum, there is the prevalence of the xenosaprobic and oligosaprobic forms. The halophobe and oligohalobe species dominate in the halobic spectrum, while a more uniform distribution is present in the various levels of the trophic spectrum. In the upper torrential stretches, some species such as Diatoma hyemalis and Eucocconeis flexella occur. They are extremely sensitive to organic and mineral pollution and thus risk disappearing as anthropogenic pressure increases upstream. Nevertheless, on the basis of the data obtained, it seems that the situation of the watercourses here considered is still, as a whole, in moderately good conditions. The high sensitivity of the rheophile diatoms to environmental factors allowed to work out an index for monitoring Apennine rivers, named EPI-D, that has proven quite useful also for rivers of other hydroecoregions, either in Italy or in Europe.