Changes in species diversity and threats to the avifauna of river valleys of the Kuyavian-Pomeranian Voivodeship, comprising part of the international waterway E-70

Abstract

The Noteć, Vistula and Brda rivers and their valleys, comprising a part of the modernized international waterway E-70 in Poland, despite undergoing extensive transformations in the 20th century, still represent nature values which are unique not only in the scale of the Kuyavian-Pomeranian region, but also in the national and continental scale. Further alterations of the river valleys as a consequence of modernization of the E-70 international waterway will intensify the negative trend of changes in breeding and migrating avifauna. An example supporting this assumption is i.a. the Noteć river and the Bydgoski Canal valley, where during the past 25-30 years a significant decrease in the breeding populations of many bird species was recorded (Limosa limosa, Vanellus vanellus, Numenius arquata, Gallinago gallinago, Anas querquedula, Anas clypeata, Porzana porzana), and some of them eventually ceased to nest in the valley (e.g. Podiceps grisegena, Aythya ferina and Aythya fuligula). The most important factor guaranteeing the preservation of the exceptional diversity of the locally existing habitats together with animal and plant species occurring there, as well as material culture, is particular consideration, circumspection and responsibility in making decisions regardingmodernization of the E-70 waterway, especially interms of environmental impact assessments of the planned investment.