Ecological groups of birds of Zhytomyr region (Ukraine) in relation to thermal regime and their future prospects in the context of global climate change
Authors: Tkachuk R. , Nykytiuk Y. , Komorna О. , Kravchenko O. , Zymaroieva A. 
Published: November 2024

The potential impact of global climate change on the distribution of bird species can be predicted based on observed climate change and current knowledge of the factors affecting range boundaries. The concept of an ecological niche allows one to qualitatively and quantitatively characterise the impact of environmental factors on species. The study estimates the parameters of the thermal projection of the ecological niche of birds in Zhytomyr region, compares different approaches to modelling the response of species to the average annual temperature gradient, identifies ecological groups of birds based on their thermal gradient, and provides prospects for these ecological groups in the context of global climate change. The beta-function was found to reflect the reactions of different species within a single bell-shaped pattern across the entire gradient of the environmental factor. This makes it possible to estimate the optimal level for all bird species. Kurtosis can be used to distinguish between different response patterns within the beta model. Zero kurtosis indicates a symmetrical bell-shaped response. The relationship between the kurtosis of species response models and the optimum is complex. In general, species show negative kurtosis in the warm part of the range, indicating a sharp break in the species response curve in the warm part of the factor range. In the middle part of the factor range, the kurtosis value randomly fluctuates around zero, indicating a predominant tendency towards symmetrical response forms and the prevalence of the classical bell-shaped response model. The limits of variation of kurtosis are of great importance in the cold part of the range. The thermal projection of the ecological niche was used to divide bird species into ecological groups based on the position of the optimum zone and the width of the tolerance amplitude. It is shown that ecological groups differ in their prospects under global climate change. Stenotopic megatherms have the best prospects in the face of global climate change. The habitat conditions of all other bird species in the region will deteriorate over the next 70 years. The most threatening prospects should be expected for stenotopic microtherms. The stenotopic megatherms include 68 species, which is 25.9% of the total regional bird fauna. That is, global climate change poses a threat to 74.1% of the region's bird species. Stenotopic megatherms are typified by Anseriformes, Bucerotiformes, Gruiformes, and Pelecaniformes. It was predicted that Ciconia ciconia has the greatest prospects for expansion due to global climate change. The stenotopic microtherms are represented by 18 species, which is 6.9% of the regional avifauna. For these species, climatic conditions will significantly limit the number of favourable habitats. This ecological group is most strongly typified by for Galliformes, Piciformes, and Strigiformes. Climate change will lead to a shift in the range of Picus canus, which will reduce the abundance of this species in the region.