1. An ecological investigation of the shore fly community was carried out in a salt marsh in Novosedly in the Czech Republic. 2. Sampling was carried out in 1997 and 1999 at approximately 14-day intervals during the seasonally active period, using yellow water traps.
3. Altogether 14 374 specimens of the family Ephydridae were collected (6040 in 1997 and 8334 in 1999), belonging to 48 shore fly species (37 in 1997 and 41 in 1999).
4. Community structure, species richness, species diversity, evenness, and seasonal and inter-annual changes were studied. The species richness, species diversity, and evenness of the shore fly community in 1999 were higher than in 1997 but inter-annual difference in species diversity was not statistically significant. Paracoenia fumosa, Scatella tenuicosta, and Hydrellia albilabris were found to be the most abundant species in both study years.
5. Seasonal patterns and phenology of the most abundant species are discussed. Hydrellia albilabris showed similar seasonal distribution of abundance in 1997 and 1999, whereas seasonal distribution of P. fumosa and S. tenuicosta varied between the study years. Paracoenia fumosa, Hydrellia griseola, H. albilabris, Scatella paludum, S. tenuicosta, and Philotelma defecta were found to occur throughout the whole observation period from March until November while Notiphila cinerea, Hydrellia ischiaca, and Psilopa nigritella appeared in a limited period only.
