Species Composition of Macrozoobenthos of Water Bodies of the Khvalynsky National Park (Saratov Region, Russia)

In 2021–2022, a benthic survey was conducted in eight small water bodies within the protected and recreational zones of the Khvalynsky National Park (Saratov region): the Blagodatny spring, a pond near the Solnechnaya Polyana tourist complex, Losinoye Lake, the Bely Klyuch pond, the Yeleshnikovsky pond, a small temporary water body, the Balalayka pond, and the Steklyashka pond. A total of 76 hydrobiont taxa were recorded: oligochaetes – 3, leeches – 3, bivalves – 2, gastropods – 7, crustaceans – 2, water mites – 1, stonefly larvae – 1, mayfly larvae – 4, dragonfly larvae – 6, beetle larvae – 4, true bug larvae – 2, moth larvae – 1, humpbacked fly larvae – 1, alderfly larvae – 1, chironomid larvae – 29, phantom midge larvae – 1, marsh fly larvae – 1, stiletto fly larvae – 1, moth fly larvae – 1, biting midge larvae – 1, horsefly larvae – 1, crane fly larvae – 1, and caddisflies – 2. In the studied water bodies, the dominant species included the oligochaete Limnodrilus hoffmeisteri (Claparède, 1862), the leech Helobdella stagnalis (Linnaeus, 1758), the bivalve Sphaerium rivicola (Lamarck, 1818), the gastropods Lymnaea atra (Schrank, 1803) and Lymnaea truncatula (O.F. Müller, 1774), the dragonfly Sympetrum flaveolum (Linnaeus, 1758), the mayfly Caenis horaria (Linnaeus, 1758), and chironomids – Chironomus sp. The highest species diversity was found in the pond near the Solnechnaya Polyana tourist complex. Springs were dominated by rheophilic and oxyphilic species, such as those from the genera Stygobromus and Prodiamesa, while ponds were characterized by species associated with vegetation or silty substrates. Among the identified species, the beautiful demoiselle (Calopteryx virgo Linnaeus, 1758) is listed in the Red Book of Saratov region.