Research Information System
37th International Scientific Conference on Economic and Social Development - Socio Economic Problems of Sustainable Development, Baku, Azerbaijan, 14 - 15 February 2019, pp.985-988
The paper presents new data on species composition, number and distribution of the larvae of dragonflies (Odonata) in new environmental conditions of the different habitats of in the lake Mehman. Field works conducted in 2015 - 2017 in the lake Mehman resulted in the rearings of 25 species and forms of dragonfly larvae. Seven of these L. nympha, S. fusca, E. viridulum, pumilio, O. concellatum, L. depressa, L. quadrimaculata, Cordulia sp. are new to the lake. Species Lestes virens, and Lelegans, were found in winter, spring and autumn of 2015 and winter and autumn of 2017; C.scitulumin winter and autumn of 2015; C.hastulatum - winter, spring and autumn of 2017; E.fatimein winter and autumn of 2015 - 2017; in winter and spring . of 2015 - 2017. Species C. mercuriale, C. scitulum, L. virens, elegans, C. puella, E. najas, O. albistylum are observed in the lake in all seasons and are dominated by widespread. It should be noted that the decrease in the number of larvae of dragonflies in the summer, especially at depths of up to 0.5 m is due to their intensive consumption by fish and water birds and emergence of adult dragonflies which leave the lake. On the other hand, in summer period, the volume of oxygen in shallow water of the lake Mehman greatly reduced, and asa result of evaporation of water, the amount of salts in water is increased. In such circumstances, the probability of occurrence of freshwater organisms in the benthos is naturally decreased. The study of the distribution of larvae of dragonflies on specific habitats of the lake revealed their maximum development on plant and silty habitats, and the minimum - on black silty sand. Changes in biomass of benthic organisms as well as larvae of dragonflies, which developed very poor is analyzed. Poor development of dragonfly larvae in the lake Mehman characterized, on the one hand with their intensive consumption by fish and water birds and on the other hand - the steady worsening of the environmental conditions of the lake.