Abstract:Cobadin Plateau (subunit of Negru Vodă Plateau, South Dobrogea) is located in the extreme south-eastern part of Romania. Its landscape consists of large and almost flat interfluves. There start a series of short valleys discharging into the Danube River. To the west, it is bordered by Oltina Plateau, taller and stronger fragmented by valleys of canyon type. To the east, the plateau is bordered by Black Sea. Karst phenomena (sinkholes and poles) are present below. The paper examines biogeographic point of view two populations of Chondrula tridens (Tree Tooth Bulin Snail) identified in Cobadin Plateau (South-East Dobrogea), in period 2009-2012. Specimens were taken from two areas geographically close (10 km distance between them), but ecologically different.

Conacu-Negreṣti Valley is located in the center of Cobadin Plateau, subunit of Negru Vodă Plateau, South Dobrogea, Romania. It landscape consists predominantly of Cretaceous and Sarmatian limestone, placed on a Precambrian background and covered by a thick blanket of 40 m of Quaternary loess. The valley is characterized by an extremely rich and diverse geo-biodiversity with many rare and endemic species of wildlife Dobrogea and Romania, too. The paper presents the floral diversity identified so far in this valley, focusing on the description of 12 species of rare and endemic plants identified in the area, species of great scientific and practical importance. The data represent the results of the research activities developed within the framework of our scientific and educational program on geo-bio-diversity and its protection of the Conacu-Negreṣti Valley from 2002 until now.