Home – Home – Jornals – Contemporary Problems of Ecology 2002 number 6

For 53 out of 57 species and subspecies of dragon flies in the fauna of the Pamir-Alai, the range of altitudinal diffusion and optima in the altitudinal component of their distribution area have been established. Distinguished are mountainous species (13), lowland species (10), those with optima of the area in the mountains (16) and in plains (11), and 3 species of obligate migrants with vaguely expressed optima. The vertical diffusion of dragon flies is determined by climatic factors, first of alltemperature, with existence of reproductive stations. In the latter case, the most important role is played by the anthropogenous factor. With the advent and development of artificial irrigation systems, the pattern of vertical diffusion of dragon flies in the Pamir-Alai, like in general in the south of Middle Asia, has radically changed. Some initially montane species have succeeded in populating plains with desert climate, and the majority of lowland and euryzonal ones have considerably enlarged their distribution areas.