Bitterling Populations in The Sighisoara-Târnava Mare Natura 2000 Site ‒ A Support System for Management Decisions

The predominant threats to the Bitterling populations in the Sighisoara-Târnava Mare Natura 2000 site are the hydro technical modifications of the river channels, organic contamination and illegal fishing. ADONIS:CE is applied commonly for business processes modelling, however, in this study case was applied in an ecology/biology sphere of interest. The authors acquired a Bitterling model which contained all of the identified habitat species’ necessities, the specific indicators that give good preservation status and the present pressures and threats. The keeping of the riverbed morphodynamics is especially necessary - the meanders existence is significant for the aquatic mollusc species which are existing in the inner U shape sectors of the lotic systems. The sectors, where the sand and mud are relatively fixed, give appropriate habitats for molluscs which is valuable for the reproduction of Bitterling. The preserving of the present water oxygenation and regime of liquid flows, and the prevention of the sediments deposition rate in the aquatic habitats are needed too for the molluscs’ existence. The sediments exploitation in these lotic systems should be realised in relation with the natural rate of renewal and at sites at a distance over five km between them.