Rozenfeld S.B., Sheremetyev I.S.
Journal of general biology 2016; 77(1): 16-37
Geese (Anser) and brants (Branta) are important elements of Arctic ecosystems, which stimulates worldwide scientific interest in researches of their biology. Due to this interest, a great amount of empirical data is accumulated including detailed descriptions of morphology, nesting peculiarities, trophic ecology, behavior, migrations, population geography, and other features of Arctic geese and brants. Their range extent along the Arctic coast of Eurasia depends, substantially, on population size. Therefore, all the factors influencing population size also influence, indirectly, the range extent. Geese and brants species significantly differ in population size, range extent, and tendencies in their changes over time. We compared the available data in order to find out what, in which way, and to what extent determines population size and range of geese and brants. It follows from the analysis that the main factor contributing to the reduction in population size is extermination at nesting sites and along transmigration routes, and the lack of food at sites of overwintering. Those species not using cultivated plants in winter are small in numbers. The next factor is a type of feeding that is determined by body size and the ratio between beak length and head length. The influence of all other factors that are related to patterns of feeding and nesting is much less. This may be interpreted as a result of anthropogenic impact which is hard, if at all possible, to estimate quantitatively. Disappearance of geese and brants within considerable areas in the Arctic may cause dramatic ecological consequences.
