Non-marine Ostracoda (Crustacea) as indicator species group of habitat types

To understand interactions between ecological properties of ostracod species and the habitat types, 89 different aquatic bodies with nine different habitat types were randomly visited in Artvin province, Turkey. A total of 24 taxa, all new for the province, were found from 62 sites. Shannon-Weaver alpha diversity of the numbers of species value was higher (3.972) than the mean index value of all samples (2.945) with relatively low standard error (0.264). Six species (Psychrodromus olivaceus, P. fontinalis, Heterocypris incongruens, Potamocypris fulva, P. fallax and Ilyocypris bradyi) encountered most frequently contributed more than 90% of diversity in four different habitat types (lake, creek, trough and canal) of 11 sampling sites. Two positive co-occurrences (p < 0.05) were found for P. olivaceus-I. bradyi, and P. olivaceus-I. inermis. Canonical correspondence analyses explained 60.5% of the variance between 12 asexual species and environmental variables. Water temperature, dissolved oxygen and elevation were the most predictive variables for species found in five different habitats (lake, creek, trough, canal and ditch). Ordination on the first axis of the species negative filter method characterized the sites (samples) by the presence of rare (negative indicators) and common (positive indicator) species in opposite ends. According to TWINSPAN analysis, these species as the key members (indicators) of that particular habitat(s) can be used to distinguish characteristics of habitats. Overall, multiple regression models suggested that rather than focusing on one particular species, two or more ostracod species or the so-called indicator species group can also be used for habitat type(s) and/or aquatic condition(s)