Abstract
Oligochaeta of forest vernal pools and small draining ditches were sampled together with other aquatic macroinvertebrates yearly in spring 2013–2018 at six sites in the eastern part of Tartu County, Estonia. In 298 samples, a limited number of oligochaete taxa (23) was found. The most common species were Lumbriculus variegatus (2/3 of all individuals sampled), Cognettia glandulosa, Tubifex tubifex and Aulodrilus limnobius, all able to reproduce rapidly in asexual way, either by architomy or parthenogenesis. The phytophilous Naididae were rare or lacking, as were most of the other Tubificidae, common in permanent water bodies, and the majority of the soil-inhabiting Enchytraeidae and Lumbricidae. Some in general rheophilous Lumbriculidae (Rhynchelmis tetratheca, Stylodrilus heringianus, S. brachystylus) apparently live permanently in the humid soil under several temporary pools. Vernal temporary waters seem to be a specific habitat for the naidid Bratislavia palmeni. The oligochaete fauna was almost similar in the natural pools of drained and undrained forests, slightly more diverse in draining ditches, and the poorest in recently dug mitigation pools.