In a survey such as this, along a longitudinal riverine gradient, there is a possibility of inadvertently including several species in a single analysis, thus we first evaluated whether cryptic species were present using a multi-dimensional scaling (MDS) approach (e.g. , Johns et al., 1997, Hebert et al., 2003). We employed the cmdscale function in R (R Core Development Team, 2005) to explored our data in 2 and 3 dimensions using a pairwise distance matrix among all 346 individual genotypes. The distance between individuals A & B was calculated as 1 – 2C/ (A+B) where C=the number of common bands, and A and B represent the number of unique bands in the two individuals.

คือไม่ค่อยมีความรู้ทางด้านสถิติครับ ช่วยกรุณาด้วยครับ ไม่เข้าใจว่า cmdscale function in R (R Core Development Team, 2005) หมายถึงอะไรหรอครับ หาข้อมูลแล้วไม่มีเลยครับ