Short-term restoration of riverine bird assemblages after a severe flood

Abstract

Capsule Diversity and abundance of birds breeding in river channels increased significantly after a severe flood in southern Poland. Flooding increased the diversity of river channels, especially on previously regulated sections, and this resulted in more breeding habitat for birds. Aims To investigate how a severe flood can alter river assemblages of bird species breeding in natural pre-flood or regulated sections. Methods Data of breeding birds within submontane river channels in southern Poland from before (2007-2009) and after (2011) a flood were collected. Bird diversity and abundance in natural and pre-flood regulated sections were compared before and after the flood. Results The presence of natural features within channels increased significantly in all the studied sections. The number of bird species and breeding pairs increased both in the regulated and natural channel sections, but was much larger in the previously regulated sections. Conclusion The underlying cause of the observed short-term increase in species and their population size was thought to be a combination of increased breeding site availability and food abundance. Floods are a major factor in river channel restoration. © 2013 British Trust for Ornithology.