Биоценотические связи сайгаков с крупными хищными птицами

Abstract

Conservation of biodiversity has recently become the most urgent task due to global anthropogenic transformation of the environment. Therefore, more and more attention is being paid to the role of species in biogeocenosis, their biocoenotic relationships, and the assessment of ongoing changes. Due to the unprecedented growth of the Ural Saiga (Saiga tatarica) population, the study of ecology, behavior, and biocenotic relationships as factors affecting the structure of the ecosystem and, in particular, large birds of prey has become increasingly important. The saiga population in West Kazakhstan Region in 2023 is estimated at 1.13 million individuals, which is highly concentrated in Zhanibek (8,200 km2), Bokeyordinsky (19,214 km2), and Kaztalovsky (18,600 km2) districts of the region. And here we should pay attention to the fact that with anthropogenic changes in the habitat (construction of roads, canals, gas and oil pipelines, etc.), macroevolutionary changes in saiga behavior have begun to occur – saigas are no longer the nomadic species they were 100 years ago, they no longer nomade over great distances, and are becoming more sedentary. Our observations show that saigas do not travel more than 100 km and stay mainly around sors (dried up salt lakes). The next fact is that from late November to early December, saigas start their rut. As a result of extreme exhaustion during the rut, up to 96% of males die. The huge biomass accumulates in a relatively small area. This cannot cause the population of predators and scavengers to grow. The growth of predatory mammals is limited by the availability of accessible drinking water, so we did not observe an increase in the population of wolves, but the number of jackals and steppe cats increased. The growth of jackals is possible not only due to the availability of food in the autumnwinter period, but also due to increased hunting pressure in neighboring areas of the Russian Federation. The growth of the steppe cat (which is most abundant in the Bokeyordinsky district) may be due to the growth of saigas, as it has been reported that saiga remains have been found in the cat's stomach. The above-mentioned districts of West Kazakhstan Region have the highest density of large birds of prey. There are both direct and indirect biocoenotic links between saigas and large birds of prey – Steppe Eagle (Aquila nipalensis), Imperial Eagle (Aquila heliaca), White-Tailed Eagle (Haliaeetus albicilla), Cinereous Vulture (Aegypius monachus), and Eurasian Griffon Vulture (Gyps fulvus). Studies, both our own and those of the Association for the Conservation of Biodiversity of Kazakhstan (ACBK), show a high density of the breeding of Steppe Eagles in West Kazakhstan Region (WKR) in areas where saigas congregate, especially in the Kaztalovsky District, while in other areas of the region their numbers are very low. Its direct and indirect biocenotic relationship with saigas can be traced here: – Direct. All the nests we examined contained saiga remains. We have never seen Steppe Eagles hunting saigas, most likely picking up fallen or sick individuals, as well as the afterbirths of saiga calves. We saw a Steppe Eagle eating a saiga (most likely it was hit by a car, as its ribs were broken), the peritoneum was opened, internal organs were lying separately, the eagle did not eat them. It mostly pecked meat from the thighs of the hind legs. The carcass was fresh, blood had not coagulated yet. In the area of Araltobe Sor on 20/08/2020 we observed a large pre-migration concentration of the Steppe Eagle of about 300 individuals. – Indirect. In areas where saigas graze there is a high number of the Little Ground Squirrel (Spermophilus pygmaeus), the main food object of the Steppe Eagle. By regulating the height of grass stands, favorable conditions for the Little Ground Squirrel are created. In other areas of the region, the Little Ground Squirrel has become rare. The White-Tailed Eagle (Haliaeetus albicilla) is abundant during winter migration in areas where saigas congregate: On November 15, 2021, we counted 43 individuals following a herd of saigas on the 100 km Kaztalovka – Khan Ordasy road route. In recent years, we have recorded annual visitations of the Black Vulture (Aegypius monachus) in the region. We attribute this to the growth of the saiga population. In 2019, we recorded an encounter of the Eurasian Griffon Vulture in the vicinity of Saihin settlement, which is the first record for the last 50 years. Analyzing all of the above, we can conclude that the growth of saiga population positively affects the dynamics of population growth of large birds of prey in the West Kazakhstan Region.