Export of aquatic productivity, including highly unsaturated fatty acids, to terrestrial ecosystems via Odonata

Abstract

Based on 31-year field study of the abundance and biomass of 18 species of odonates in the Barabinsk Forest– Steppe(Western Siberia, Russia),we quantified the contribution of odonates to the export of aquatic productivity to surrounding terrestrial landscape. Emergence varied from 0.8 to 4.9 g of wet biomass per m2 of land area per year. Average export of organic carbon was estimated to be 0.30 g·m−2·year−1, which is comparable with the average production of herbivorous terrestrial insects in temperate grasslands. Moreover, in contrast to terrestrial insects, emerging odonates contained high quantities of highly unsaturated fatty acids (HUFA), namely eicosapentaenoic acid (20:5n-3, EPA), and docosahexaenoic acid (22:6n-3, DHA), which are known to be essential for many terrestrial animals, especially for birds. The export of EPA+DHA by odonates was found to be 1.92– 11.76 mg·m−2·year−1, which is equal to an average general estimation of the export of HUFA by emerging aquatic insects. Therefore, odonates appeared to be a quantitatively and qualitatively important conduit of aquatic productivity to forest-steppe ecosystem.