Petrifying Springs of Lviv Roztocze and adjacent territories: the Retrospective and Modern Condition

Abstract

Eighty-four hard-water petrifying springs of Lviv Roztocze and adjacent territories, which are forming 18 streams, were examined and their current state was assessed. The geographical position, geomorphological features, conditions of water sources and spring beds, character of tufa-forming processes, shapes of tufa formations and vegetation composition were described for each location. It was established, that travertine springs on the studied territory are related to the sources of small rivers associated with water-erosive landscape complexes. The high mineralization of groundwater, the specific structure of the river-erosion network, the location in a moisture warm climate zone, the development of colonies of calciphilic organisms (cyanobacteria, algae, bryophytes) at the watercourses led to the formation of a large travertine deposits here in the past. At the present time, the complex of natural factors is often accompanied by anthropogenic influence due to a long period of modification of the water resources of The Roztocze region. Now most of the petrifying springs are transformed by human activity, which significantly affects the intensity of tufa-forming processes. It was established, that a high level of anthropopression led to the transformation of most tufagenic watercourses and a decrease in the intensity of their activity: complete (when the processes of tufa genesis are stopped) or partial (when the processes slow downed or returned to the initial stage). Our survey of 84 sources showed that the majority of them are markedly anthropized (63.1%), about a quarter (23.8%) are lightly modified and are semi-natural in origin, and only a small part of them have a natural character now (13.1%). Among the four travertine formations known from the end of the 19th century, only two have survived (Chepin streams, Hamulets streams), while two more have been completely destroyed (Berekavitsa streams, the springhead of the Kabanivka river). It should be noted, that the active zone of tufa accumulation has noticeably decreased on 5 streams with natural or semi-natural sources (cascade on Hamulets stream, cascade on Hrybovytskyi stream, the left tributary of Chyshkivskyi stream, cascade on Chepin stream, a travertine body at the site of the bath container in Lysynytskyi stream). Tufa accumulation processes at 21 sources (25.0%) were artificially returned to the initial stage of formation due to the destruction of previously generated deposits there. Natural travertine formations of the region mainly have the form of cascades, rarely - waterfalls or crests and anthropogenic ones are mostly covered by concrete trunk. Regardless of their artificial origin, anthropogenic wells can be valuable habitats for the habitats of calciphilic bryophytes in urbanized areas. Natural and semi-natural travertine springs with saved biodiversity are can be potential objects of the Emerald network of the Roztocze region.