Tomasz Buczek, Alicja Buczek
Ornis Polonica 2017, 58: 215–243
https://doi.org/10.12657/ornis.2017.4.0
Abstract: This paper presents the results of avifauna surveys conducted for 30 years (1986–2015) on Chełmskie Torfowiska Węglanowe (E Poland), which is a Special Protection Area Natura 2000 PLB060002 (4309 ha in size). The alkaline nature of peat determines the occurrence of unique vegetation communities, e.g. rushes of Cladietum marisci (753 ha). These marshes owe their status to Great Snipe Gallinago media (10–12 displaying males in 2014) and Aquatic Warbler Acrocephalus paludicola (270 singing males in 2014). In 1986–2015 the number of the following wader species: Lapwing Vanellus vanellus (145 pairs in 1987 – 12 pairs in 2011), Black-tailed Godwit Limosa limosa (73 pairs in 1987 – 9 pairs in 2011) and Redshank Tringa totanus (23 pairs in 1987 – 3 pairs in 2011) have declined in the bogs Bagno Serebryskie, Brzeźno and Roskosz. The last record of the Curlew Numenius arquata breeding (max. 8 pairs in 1993) was observed in 2003. Some decrease has been noted in the population of Marsh Harrier Circus aeruginosus (65 pairs in 1992 – 10 pairs in 2015) and Montagu’s Harrier C. pygargus (43 pairs in 1987 – 2 pairs in 2015 and 0 pairs in 2016). Among species nesting occasionally are White-winged Black Tern Chlidonias leucopterus (max. 515 pairs in 2013) and Short-eared Owl Asio flammeus (max. 11 pairs in 1990). The breeding populations of Bittern Botaurus stellaris (6–7 males in 1985 – 22–23 males in 2015) and Crane Grus grus (1 pair in 1987 – 9 pairs in 2011) increased in number during the studied period. The number of Aquatic Warblers is generally stable in plots, in control areas as well as in the whole area of studies. Increased predation pressure, landscape changes (cutting down trees and bushes), changes in vegetation structure due to reed Phragmites australis expansion, local changes in water level owing to beaver Castor fiber activity, discontinuation of meadow use and conversion of meadows to arable land have been recognized as the local causes of disappearance or changes in the number of the studied avian species.
Keywords: Aquatic Warbler, breeding birds, Chelm Calcerous Marshes, eastern Poland, Great Snipe, Special Protection Area
