Ecological Status of the River Sazliyka and its Tributaries (Southern Bulgaria) as Indicated by Developmental Stability of Pelophylax ridibundus (Amphibia: Ranidae)

摘要

In the present work we did a bio-indicational assessment of the ecological status of the river Sazliyka (Southern Bulgaria) and two of its left tributaries (the rivers Blatnitsa and Sokolitsa), based on the integral indicator for the developmental stability - fluctuating asymmetry (FA) in the populations of the marsh frog Pelophylax ridibundus. Seven biotopes upstream to the mouth of the Sazliyka River, and one and four biotopes along the rivers Blatnisa and Skokolitsa, respectively, were examined. Based on the indicators for FA, grade rating was assigned, and it was also done as a characteristic of the living environment in these biotopes, parallel and independently of the data from the physicochemical analysis.