The study was conducted in the landscapes of south-eastern Ukraine during the nesting seasons 1988–2018. Within the landscape system associated with the Molochny Estuary, the ten most important ecosystem types were investigated, including the following: agricultural land, vegetated strips, meadows, islands and spits, reedbeds, urban areas, salt marshes, steppe, cliffs, artificial forests. Bird species responded to temperature and precipitation gradients. The patterns of responses were presented using Huisman, Olff and Fresco expanded by the Jansen-Oksanen hierarchical models. The nature of species response in the gradient of temperature or precipitation conditions depends on the type of particular ecosystem and is not uniform for all populations inhabiting the different landscape types. The bird communities were revealed to demonstrate an abrupt dynamic over time. The continuous changes in community structure initiated by the external environmental factors are combined with modifications of internal biotic interactions, which may lead to abrupt reorganization of the community.

The challenge of searching for patterns of species turnover dynamics in communities of living organisms is directly related to solving problems of stability and functioning of ecosystems. Avian communities are an essential structural and functional component of terrestrial and aquatic ecosystems which are highly diverse and play an important role in a wide range of ecosystem functions. The issue of changes in the dynamics of amphibiotic landscape complexes, where terrestrial and aquatic ecosystems conjugate, is practically not solved. In this connection, a study was carried out within a landscape system, which presents terrestrial and aquatic ecosystems that were in different degrees of anthropogenic transformation. The dynamics of bird communities was considered in the context of recent global climate change. The investigation was conducted in the landscapes of the south and south-east of Ukraine in the nesting seasons 1988–2018. Within the landscape system associated with the Molochny estuary, the ten most important types of ecosystems were distinguished, which included : agricultural lands, artificial forest belts, meadows, islands and spits, reed beds, urban areas, solonchaks, steppe, cliffs, artificial forests. The temporal turnover of the bird communities was decomposed into two parts: the first term (D1) related to the amount of change in community composition, and the second term (D2) being dependent only on the amount of change in community size sensu its abundance. The contribution ratio of the species and of the environment variable were calculated to identify drivers that influence the turnover measure. The average annual temperature and the sum of annual temperatures were considered as environment variables. The bird metacommunity of the studied landscape system was represented by 132 species from 86 genera, 42 families and 13 orders. During the research period the average annual temperature varied from 9.5 to 12.5 ˚C. and the temperature dynamics were subject to the linear trend. An oscillatory component was also present in the temperature dynamics. The annual rainfall ranged 220–761 mm. A coherent change in precipitation and temperature was observed in the period until 2011. After that, the temperature growth stabilized and the amount of precipitation began to fall sharply. The steppe bird community was represented by an extremely small number of species, but demonstrated the ability to maintain a stable structure for a long time. The main fluctuations of the community were quantitative changes in abundance, while the turnover of species was practically absent. Species of the community replace each other cyclically, but there were no targeted changes in community structure. Temperature and precipitation were the main drivers of the bird community in the steppe. The bird communities on salt marshes were characterized by a stable abundance, but a constant directed turnover of species. Reduced water levels and the disappearance of islands in the salt marshes increased the risk of threats from predators, which could lead to a decrease in the abundance of some species. The islands and spits were characterized by high species turnover with quasi-cyclical population dynamics. The main feature of the community dynamics was a decrease in the role of precipitation and an increase in the role of the time factor. The role of temperature remained stably low. The species richness of bird communities in agrarian lands was higher than in steppe communities. The turnover measure was significant because of the increased abundance of Alauda arvensis. Over time, the role of precipitation in the community dynamics has been decreasing and the role of time has been increasing. The value of temperature varied, but was at a stationary level. The turnover of species was compensated by an increase in the abundance of bird communities. The obtained results are in line with findings indicating that despite more stable land use intensities in recent years, climate change has not overtaken land use intensities as the main driver of bird population dynamics.

This study discussed the importance of the phylogenetic components in the structure of bird communities of anthropogenically transformed ecosystems. The investigation was conducted in the landscapes of the south and south-east of Ukraine in the nesting seasons 1988–2018. The bird community in the agricultural landscape was found to be presented by 10 species. The number of species was closely correlated with its phylogenetic analogue – Faith’s index. Both indices were stationary over time, as they do not show a statistically significant time trend. The two axes were extracted as a result of the DPCOA procedure and the permutation test showed their statistical significance. The axis 1 was the most sensitive to the opposite dynamics of the abundance of Coturnix coturnix and Burhinus oedicnemus on the one hand and Alauda arvensis and Melanocorypha calandra on the other. The axis 2 is the most sensitive to the opposite dynamics of Corvus monedula and Melanocorypha calandra on the one hand and Coturnix coturnix and Motacilla flava on the other. Based on phylogenetic diversity, the years can be clustered with the extraction of four relatively homogeneous phylogenetic structures of bird communities. The indicator of the initial period of dynamics (1988–1992) was Burhinus oedicnemus. Sowing or mechanical weeding may be considered as a major factor of nest destruction of Burhinus oedicnemus. The decreasing of the abundance of the trophic recourses because of agricultural activity may have caused the monotonous negative trend over time of the Burhinus oedicnemus populations. The period 1993–2003 was a transitional one, for which there were no clear indicators, as a characteristic feature of this period was the processes of bird community restructuring. The period 2004–2013 was characterized by the loss of Burhinus oedicnemus from the community and a sharp increase in the abundance of Corvus monedula. These species are distinguished by their phylogenetic specificity and are located on the periphery relative to the phylogenetic core of the community. There was growing importance in the community of such species as Alauda arvensis, Anthus campestris, and Melanocorypha calandra between 2014 and 2018. Our results also confirm the assumption that phylogenetic overdispersion is an important requirement for the stability of the bird community in anthropogenically transformed landscapes.

This study presents the results of a long term study of nesting colonies of the Caspian gull (Larus cachinnans Pallas, 1811) on the islands of the Molochniy Liman and in Obitochnaya Bay (Azov Sea), in the South of Ukraine (Zaporizhia region), conducted between 1988 and 2013. A description of the size and coloring of eggs of Caspian gull was conducted by generally accepted methods. We measured 1000 eggs from 5 colonies of Caspian gulls. The background coloration of the eggs’ shells was classified into 7 types, the pattern of markings on the surface of the shells was classified into 4 types. In the nesting colonies, comprising different nesting settlements, the study tested differences in the distribution of typical and atypical coloring types and patterns on the surface of the shells. The background color and character of the shell marking patterns is dominated by eggs of phenotypes 3 and 4: gray-green, with a pattern of spots, of medium size (5–60%) and brown, with a pattern of large spots (2–40%). In different settlements the Caspian gull egg sizes vary in length and diameter of 54.5–86.3 x 39.2–60.4 mm, volume 61.7–113.7 cm3 and index of roundness 63.6–85.3%. The study revealed that the linear dimensions of eggs also depend on the number of birds in the nesting colonies. We found that morphological and dimensional characteristics of Caspian gull eggs can vary at certain intervals and characterize individual colonies, settlements and populations. Based on cluster analysis, conducted in terms of the average of the linear sizes of eggs of Caspian gull from several populations within the range of the species, the study identified three groups of colonies – Danube-Sivash, Azov-Black Sea and Caucasus-Caspian. In region of the Azov-Black Sea, the greatest similarity was shown between the settlements of Sivash and the South of Crimea, which in turn is similar to Lebiyazhyi Islands and Kaniv Nature Reserve (river Dnipro). A related link combined the Azov and Black Sea branches, while the Caucasus-Caspian group is relatively separate. As a result this study the influence of the number of nesting birds on the dimensional characteristics of the eggs was established; in the period of increase in the Caspian gull population from the 1970s to the early 1990s they had the highest scores, and in periods of decreasing population in 2001–2005, their values were lowest. Consequently, the use of oomorphological indicators turned out to be a fairly easy and objective method for studying the monitoring data for separate colonial bird species.

The effect of the pyrogenic factor on the avifauna of shelter belts in the north-western part of the Azov Sea region, Ukraine is considered basing on results of the research carried out in 2001–2018. The breeding bird community of shelter belts is composed of 50 species, of them different types of shelter belts support 14–46 species. Changes in the species composition of breeding birds are analysed in subsequent years aft er the fires. The recovery of bird communities is progressing at a slow pace following the regeneration of tree-shrub vegetation and development of consortial relations of birds with dominating tree-shrub species and rook (Corvus frugilegus) colonies. It is established that the vegetation pyrogenic succession is accompanied by deep qualitative and quantitative changes in the structure of breeding avian communities in shelter belts of different type.