Benthic community studies in the Piave River estuary (North Italy).
Macrobenthic community distributions in the estuary of the Piave River were analysed in June 1997. A limnetic zone (river), a limnetic-oligohaline zone (head of estuary), an oligo-mesohaline zone (upper estuary) and a meso-polyhaline zone (middle estuary) were identified on the basis of macrobenthic community distribution and salinity gradient. Tubificidae (Limnodrilus sp.) and Chironomidae larvae (Chironomus gr. plumosus, Chironomus, gr. thummi, Isocladius gr. sylvestris, Cladotanytarsus sp., Tanytarsus sp.) were dominant in the limnetic and limnetic-oligohaline zones; estuarine species (Heterochaeta costata and Hediste diversicolor) characterized the oligo-mesohaline zone and in the meso-polyhaline zone, next to estuarine species such as H. costata, H. diversicolor, Streblospio shrubsolii and Neanthes succinea, euryhaline marine species were found. Macrobenthic community distributions showed a clear pattern of decreasing diversity in the middle of the estuary.