Natalia Królikowska
Ornis Polonica 2017, 58: 12–25
https://doi.org/10.12657/ornis.2017.1.1
Abstract: The aim of this paper was to assess the number of breeding bird species inhabiting an open landscape of the river valley within the Rogaliński Landscape Park, as well as population trends of some species based on historical data. The breeding bird species of the Warta River Valley between Śrem and Mosina (37 km2) were surveyed in 2012–2013. General linear mixed models were applied to calculate the population trends. Sixteen bird species listed in an Appendix 1 of the Council Directive 79/409/EEC of 2 April 1979 on the conservation of wild birds bred in the study area, indicating its high importance for protection of birds associated with river valleys (nesting of 0.5% of the national breeding population of Black Tern Chlidonias niger and 1% of Black Kite Milvus migrans national breeding population). All ten bird species showed negative population trends during the last 50 years, and two species (Ruff Calidris pugnax and Black-tailed Godwit Limosa limosa) has become extinct. Negative trends for breeding bird populations were most likely caused by permanent anthropogenic landscape transformations during the last 50 years (area leveling and the decline of oxbow area), changes in agriculture practices associated with the loss of typical river valley habitats. Furthermore, the creation of the Jeziorsko Reservoir resulted in the disappearance of spring flooding and unnatural fluctuation of water level in the Warta River.
Keywords: abundance trends, decline of population, river valley birds, Rogaliński Landscape Park, shorebirds
