New Record of Two Dreissenid Species (Dreissena polymorpha gallandi and Dreissena caputlacus) in Kelkit Basin (NE Anatolia): Evaluation of Morphological Divergence Based on Altitude Using Statistical Tools

Non-indigenous species in an ecosystem increase the potential of novel ecological relationships and can dramatically affect community composition and ecosystem roles. This study examined the spatial distribution of Dreissena caputlacus and Dreissena polymorpha gallandi within the Kelkit Basin located in Northeastern Anatolia. A total of 75 sampling locations representing various habitats were surveyed in the Kelkit Basin. The presence of D. p. gallandi and D. caputlacus was identified for the first time in the basin. The effects of altitude on the population structure, geographic distribution, and shell traits of D. p. gallandi and D. caputlacus were also assessed in a range of ecosystems. The highest shell length (SL) for D. caputlacus was recorded at 566 m altitude with values of 25.58 ± 5.80 mm while the highest SL value for D. p. gallandi was 24.15 ± 5.13 mm at 610 m altitude. Principal Component Analysis (PCA) revealed a strong association among shell length (SL), shell height (SH), shell width (SW), and weight (W). In conclusion, the diverse altitudinal distribution of samples strengthened the evidence that shell features differ with changes in altitude.