Marisia - Maros Megyei Múzeum Évkönyve 32-34. (2014)
Botany
Description and threats to Natura 2000 habitat 7220* Petrifying springs with tufa formations levels and flows; water pollution through nutrient enrichment by both N and P of groundwater (diffuse and point-source nutrient pollution); and the relative sensitivity in terms of critical loads for Nitrogen 15-35? Kg N ha-1 yr_1. Threats that affect the habitat indirectly include declining travertine (tufa) formation in the past 5000 years (late Holocene), in part attributable to humane encroachment and drainage of river catchments [23]. Deforestation accelerates soil erosion affecting tufa formation and the decline of travertine growth and abrasion of existing travertine sites. Accumulated nutrients are released, influencing the plant productivity that controls the travertine fabric. Organic debris (fallen trunks and boughs) is used naturally (by animals like beavers) to build dams as sites for tufa barrages. Both its removal and the loss of those animal populations that help to gather the debris can result in declining travertine formation. Deforestation also leads to direct insolation through lack of shade and increases the variation in stream temperature. Discharge and travertine deposition are affected by climatic changes with increased or reduced rainfall. Human impact is the major threat on travertine deposition through usage of water resources by humans, leading to drainage and modifications in stream regime, river flow regulation, lowering of water tables by land-use change (deforestation and afforestation). Low water flow reduces turbulence and abates removal of dissolved CO,. Consequently limestone dissolution rates are reduced, resulting in lowered levels of dissolved calcium carbonate in stream waters, and thus reduced potential for travertine formation. Deforestation, together with irrigation and urbanisation, bring about increased discharge. Mosses and algae prefer constant environmental conditions and all the threats described here lead to the elimination of travertine and vegetation. Water pollution through fertilisers, sewage and industrial waste water could have both positive and negative impacts on plant productivity and have different actions on travertine deposition. Travertines are often associated with karst environments, and these areas are frequently used by humans for the disposal of liquid and solid domestic and industrial wastes, leading to groundwater pollution of the karst. Changes in hydrodynamics follow the abstraction from streams, regarding of the channel, and construction of dams or weirs. These factors determine the increased local turbidity of streams, encouraging removal of dissolved gases and in this way serving as sites for small-scale tufa deposition. The depositional regime of tufa may be modified by alterations in channel and valley geometry, for example by quarrying of geological deposits. Additional factors may include: acid rain leading to altered pH values (in some areas of Czech Republic it is assumed to reduce travertine deposition); trampling by humans and livestock damaging the tufa fabric; and animal grazing resulting in local eutrophication. The most important additional factor is tourism, which brings together all these factors through traffic, bathing and hotels including building activities, sewage, trampling and previous deforestation. For example, in “Cheile §ugaului-Munticelu” Natural Reserve, the habitat is under threat because of a local investor, who already has destroyed a cave and collected the waters of a spring for industrial use. That spring played an important role in the local existence of the natural habitat 7220*. The original protected area („Cheile §ugaului-Munticelu” Natural Reserve) is a pSCI, being a part of the pan-European Network Natura 2000 from Romania [22]. 77
