Изменение структуры населения птиц под воздействием антропогенных факторов в долине р. Угам (Западный Тянь-Шань)

Abstract

The article addresses the issues of changes in the species composition and number of birds in the middle part of the valley of the Ugam River. The valley has been mastered by humans since ancient times, but due to its geographical location, the possibilities for conducting economic activities in it have always been limited, and its intensity has its own characteristics. Here, the location of the only settlement changed, orchards were planted and cut down, cattle were grazed everywhere or in the vicinity of the village, hayfields were mowed or abandoned, and field roads were laid and overgrown. The inclusion of the territory in the Sairam-Ugam National Park has reoriented human activities. The construction of tourist facilities has begun and continues here, which has led to an increase in the number of lovers of outdoor recreation. All this was reflected in the birds of the valley, which are very sensitive to environmental changes. This is especially noticeable in mountainous conditions, where the concentration of nesting species is not high, the main routes of migrants go along the foothills, and wintering conditions are not favorable. The first data on the avifauna of this section of the valley were obtained by M.N. Korelov in the summer and autumn of 1949 and later collected by the author in May 2003, July 2011, and 2022, which made it possible to analyse its species-specific variation. Over 70 years of observations, 127 bird species were encountered here, of which 114 were in 1949, 53 were in 2003, 54 were in 2011, and 44 were in 2022. The structure of the bird population in the valley also changed. This is especially noticeable in July 2003 and 2022, when the studies were carried out on the same days. In the first year, human activity was limited to the outskirts of the village, and in the second year, it was carried out throughout the entire section of the valley. In the first year, 617 individuals were encountered in 4 days; in the second year, 307, i.e., twice as small. In 2003, the main bird populations were Corvus corone (11.4% of the number of birds encountered), Pica pica (11.2%), Emberiza bruniceps (9.4%), Acridotheres tristis (7.3%), Emberiza cia (6.6%), Lanius minor (5.7%) and Carduelis caniceps (5.3%), and in 2022, Chloris chloris (12.4%), Ac. tristis (12.1%), C. caniceps (11.4%), Streptopelia orientalis (6.6%), C. corone (4.5%), P. pica and Em. bruniceps (3.8% each). With the development of the valley by humans, the species ratio of birds also changed. In 1949, species whose life is exclusively associated with humans were not recorded here; in 2003, 2011, and 2022, they included 5 species (Columba livia, Streptopelia senegalensis, Hirundo rustica, H. daurica, and Acridotheres tristis), which accounted for 14.2, 29.0, and 10.3% of the number of individuals encountered, respectively. The number of species indifferent to the place of residence, but preferring natural biotopes, has been stable over the years - 16, 17, 15 and 16, but changed quantitatively (50.0, 31.1 and 45.7% in 2003, 2011 and 2022). During the same period, the diversity of species living in natural biotopes also decreased (32, 27, and 25). All these and other issues are discussed in the analysis of each bird species, and it is shown that the increased anthropotization of the valley leads to a reduction in species diversity, the number of birds living here and to the loss of its uniqueness.