Breeding sites of the Aquatic Warbler in Ukraine and their conservation status. - A.M. Poluda. - Berkut. 18 (1-2). 2009. - P. 143-163.
The Aquatic Warbler (AW) is a globally threatened species. It is listed as vulnerable in the IUCN Red List and as disappearing in the Red Book of Ukraine. Information concerning distribution and number of the species in Ukraine before 1995 was almost absent. The total number in Ukraine was estimated in about 1–10 singing males. During 1995–2000 the intensive researches were carried out in Northern half of Ukraine. About 25 breeding sites were found. The total number of AW for 2000 was estimated in 2600–3400 singing males. Two population groups were found in Ukraine: the Pripyat group – 2100–2800 males and the Desna-Dnieper group – 500–600 males. During 2001–2009 the survey of about 100 new potential sites in Ukraine were carried out (incl. central, southern, eastern regions). The most part of these territories does not represent interest as potential habitats of the warbler. They were drained or were strongly transformed as a result of euthrophication. Some suitable habitats for AW in Southern and Eastern Ukraine were identified, but they are too small (not more than 10–20 ha) and located very far apart from each other (more than 100–200 km). Most likely AW could nest in these regions more than 50 years ago. New breeding sites were found only in Volyn region – in valleys of the river Pripyat (600 ha suitable biotopes and 450–550 males), river Stokhid (more 300 ha and 150–180 males), river Chornoguzka (430 ha and nearly 150 males), area between lakes Bile and Pishchane (285 ha and 120–150 males). Till beginning of 2010 30 constant breeding territories of AW are known (19 sites in Volyn region, 3 – Rivne region, 6 – Chernigiv region, 2 – Kyiv region). The total number of the Ukrainian population makes about 4200–4860 males (Desna-Dnieper group – 635–695 and Pripyat group – 3545–4167 males). Hydrological conditions of habitats are the most important factor for AW. They are related to occupation of habitats by birds and their breeding success. Therefore, the yearly dynamic of water level determines changes in number of breeding birds in specific sites. The character of dynamic water regime is essentially different for AW wetlands in two population groups. The habitats of the Desna-Dnieper population group are characterized by a relatively stable water level. Annual fluctuations of hydrological conditions are characteristic, but do not influence number of local AW groups very strongly. A completely different situation was observed in most AW habitats in Northwest Ukraine. Very strong yearly fluctuations of water level due to high river floods are characteristic for habitats in the river floodplains of Pripyat, Turya, Styr, and Stokhid. Especially critical the high waters are in breeding period (May – June), for example, in 1999 and 2005. A part of birds (sometimes all) leaves the traditional breeding sites and temporarily occupy less suitable habitats. The monitoring of 6 key settlements of AW is carried out since 2002 every year. For this purpose was chosen 2 breeding sites of the Desna-Dnipro population group (valleys of Supoy and Uday) and 4 breeding sites of the Pripyat population group (2 sites in valley of Pripyat, and in valleys of Turya and Styr). These six key breeding sites keep about 56% of Ukrainian population. In all six plots the counts of AW are carried out on routes, which usually have length of 1,5 km. The birds are counted on a strip of 200 m width. Count is started 60 minutes before sunset and continued during 80–100 minutes. Other bird species register during this count and special morning count. The information about hydrological regime and vegetation is collected also. Main breeding sites of AW are described in the article. 24% of Ukrainian AW nest on territories of protected areas. The most important from them is the National Park «Pripyat – Stokhid» (Volyn region). [Russian].
Key words: Aquatic Warbler, Acrocephalus paludicola, distribution, number, monitoring, protected areas.
Address: A.M. Poluda, Institute of Zoology, Bogdan Khmelnitsky Str. 15, 01601, Kyiv 30, Ukraine; e-mail: polud@izan.kiev.ua.