In the dissertation, we research the topic of forming of the spatio-temporal structure of breeding ornithocomplexes in a gradient of urbanization from quasi-natural to urban ecosystems of west Ukraine under influence of anthropogenic pressure, such as construction works, transport, predation by domestic animals, the introduction of allochthonous species, poaching, logging, etc.
The history of ornithological research of the region is analyzed in the gradient of urbanization: forest ecosystems, suburban ecosystems, and urban ecosystems.
In the gradient of urbanization from the quasi-natural forests of the protected areas to the central part of the city, 7 formed ornithocomplexes are identified: forests of the protected areas, suburban forests, city parks, and cemeteries; also types of buildings – villa, industrial, multi-storey built-up areas and central part of the city. It is proved that during the transition from one ornithocomplex to another there is a change in the number and density of breeding species and a significant reformatting of the species community.
Soil cover and grass vegetation as a source of feeding resources play a key role in the formation of fauna and a population of urban ecosystems. The share of species that collect food on the ground in the city center is 47.6%, and the share of their density - 81.2% of the entire bird population.
The high degree of synurbization and its long duration does not protect synanthropic species from population declines. During the 25-year research period, the number of the previously dominant house sparrow in Lviv decreased by 80.8%. The species disappear from the areas that were inhabited by it more recently (central and multi-storey parts of the city) and is now concentrated in the villa part (56.3% of the population of the species).
Dynamic trends in Blackbird populations in the urbanization gradient indicate the equalization of its nesting density in the residential part of the city: reduction of the share of participation in ornithocomplexes, where it was previously the most numerous (parks and central buildings) and growth with a very high degree of significance in other types of buildings. industrial and multi-storey).
There is a tendency for Black storks to choose wet forest types with a predominance of oak and pine. The most optimal for the species are mature and overripe forests of high-quality classes. In Polissia, most nests are located on Oaks (53.3%) and Pines (29.9%). The basis of the diet of the species are Perch, Pike, Perch, and Chinese Sleeper (30%).
It was found that within the residential part of the city the loss of vegetation between 1995 and 2018 is less than the increase, which provided an increase in the total number of the avifauna of the city during the 25-year study period by 9.8%.
Construction works and their consequences affect the formation of ornithocomplexes of urbanized ecosystems, both negatively (homogenization, reduction of species diversity) and positively (attracting sclerophyll species, repellence of natural predators). The use of new building materials is the reason for the reduction in the number of House sparrows and Sand martins in rural and urban areas.
Extermination of birds of prey on hunting grounds in Galychyna in the late nineteenth – early twentieth century and poaching in the late twentieth – early twenty-first century led to the complete extinction of such species like Osprey, Kestrel, Saker Falcon, and almost complete – Golden Eagle, White-tailed Eagle, Short-toed Eagle, and Great-spotted Eagle.
The use of introduced species of plants in urban landscaping has a negative impact on the diversity of avifauna, as it reduces the number of nesting and feeding ecological niches. Of the 52 species and genera of trees and shrubs on which birds build nests in Lviv, only 36% are located on allochthonous species.
Areas with a high diversity of avifauna occur both among greenery and buildings. The main factors that determine the diversity of the city's fauna are the richness of ecological stations and low anthropogenic load, the presence of permanent reservoirs and old stands or individual old trees.
The necessity of introducing seasonality in the functioning of protected areas around Black stork nests and dividing them into two parts – strict (100 m around the nest) and seasonal protection (500 m) is substantiated.
