Dependence of floodplain birds’ dynamics on the spring flood height and duration in the middle Ob River

Abstract

Inter-annual variations in the total number of birds in floodplains of rivers are mainly associated with their flooding. The minimum population density during the nesting period was in a year with high and prolonged spring floods. The restoration and maximum development of shrubs took place with a significant simultaneous increase in the abundance of birds in subsequent years. Drying and simplification of vegetation cover were noted in all floodplain bird habitats during low-water periods. This process was accompanied by a decline in the number of birds. We identified four groups of bird species according to the criterion of the relationship “abundance – level and duration of the flood”. In the first group of bird species, abundance increased during high floods (3 species). In the second group, the abundance decreased sharply during high and prolonged floods (7 species). In the third group, the level and duration of the spring flood did not affect the abundance (9 species). In the fourth group, a very weak tendency of the negative flood level impact on the abundance of birds was noted (6 species).