Abstract
Invertebrate and diatom communities from five springs located in the Apuseni Mountains (Transylvania, Romania) were considered for the present study. Invertebrates were sampled in winter, spring and summer 2017 using zoobenthic nets. Amphipodes and oligochetes were the most abundant and frequent taxa in all sampled springs. Stoneflies, ostracods and chironomids also recorded high abundances, but lower frequencies. No seasonal dynamics was observed, because no significant differences were identified between the sampling seasons. Similar taxa were present at every site, differing only in their relative abundances. This could be caused by the relative constancy of physico-chemical parameters measured in the sampling sites. Diatoms were only considered in summer 2017 at the same sampling sites, and the dominant taxa were identified.