Home – Home – Jornals – Contemporary Problems of Ecology 2016 number 3

The data obtained in 1995-2014 in the areas of the Sulakskaya and Turalinskaya lagoons (Dagestan, the western coast of the Middle Caspian) were summarized. The lagoons are located in a “bottleneck”, a narrow migration corridor traversed by one of the largest migration routes of trans-Palearctic species in Russia. This route is a part of the West Siberian-East African migration range. The migration traffic and territorial localization of the Laridae populations, participating in the total migratory flow along the western coast of the Caspian Sea were determined. The present-day migratory range of Laridae covering the area from Western Europe to Lake Baikal and Western India was specified. It was determined that Dagestan is crossed not by one but two independent and stable migration flows of Laridae, flying across the transit region in different migration routes but at the same periods of time. Three types of migration intensity of Laridae across the study area were defined: weak, average and mass migration. Both spring and autumn migration includes 5 peaks of migration activity (migratory waves). Timing, taxonomical composition and abundance of Laridae species vary for each degree type of migratory waves. Key determinants of migratory wave intensities are abundance of migratory populations and weather conditions of the year. It was proved that over the last 5-7 years there has been a steady decrease in abundance of some Laridae species on the western coast of the Middle Caspian. This decrease was determined by a set of factors acting across the whole migration range. Decrease in abundance of migratory Laridae leads to blurring of the boundaries between migratory waves and migration intensity. It causes changes in migration routes of some Laridae populations which now have shifted from traditional wintering grounds along the western coast of the Caspian Sea and countries of the Middle East and North-East Africa to India.