Ecological features of the formation of the floodplain faunal complex in Crimea on the example of colonial birds

As a result of the analysis of the composition and abundance of colonial species of the floodplain ecological and faunal grouping (Phalacrocorax pygmeus, Nycticorax nycticorax, Ardea cinerea, A. purpurea, Ardeola ralloides, Bubulcus ibis, Casmerodius albus, Egretta garzetta, Platalea leucorodia, Plegadis falcinellus) in the lowland Crimea, the features of their distribution on gradients of condition and resource factors were determined. The dynamics of their ecological niches has been revealed depending on the state of nesting and feeding biotopes, the influence of climatic factors and anthropogenic impact. The intensive development of hydro-reclamation, since the 1970s, has led to changes in the hydrological regime of reservoirs, the composition and productivity of the feed resource, and successional changes in vegetation. The composition and productivity of forage biotopes in terrestrial and aquatic ecosystems met the requirements of most species in the 1970s and 1990s. With the optimal state of the factors-conditions and factors-resources, there is practically no competition between species. The founders of the colonies are large heron species with a stretched nesting period, dominating the upper tier of vegetation, while small species of Ardeidae and Phalacrocorax pygmeus settle in polyspecies colonies and occupy the middle and lower tier or periphery of settlements, which provides them with protection from feathered predators.