| Реферат: | eng: Brief information on mass dragonfly migrations observed previously in Russia, and in Western Siberia in particular, is presented. From 1969 to 2009, the authors studied the dynamics of dragontly population, their spatial distribution and displacements in the West-Siberian forest-steppe. The main studies were conducted in the Chany Lake basin (the Biological Station of the Institute of Animal Systematics and Ecology, Siberian Division, Russian Academy of Sciences). The spatial redistribution of dragonflies is regarded as a balance of homing and wandering activities. Homing results in a relative stability of local dragonfly populations and communities. Wandering is a result of dispersal of dragonflies from their emergence sites and colonization of new habitats that is especially important due to the short time of existing the larval biotopes - shallow water bodies. The formation of more or less constant migration routes is a peculiar variant of wandering activities. Mass exodus from native habitats at excessive growth of the population density takes special place in dragonfly migrations. Exodus flight leads to death of all or most individuals not only. In addition, it optimizes not only the number of dragonfly populations, but also intensifies the removal of chemical elements and organic matter from eutrophic water bodies. An original generalized classification of special displacement of dragonflies is proposed.
|