Biogeography of the ‘water flea’ Daphnia O. F. Müller (Crustacea: Branchiopoda: Anomopoda) on the Indian subcontinent

Studies on Daphnia distribution in Indian subcontinent have been few and regionally restricted despite Daphnia being by far the most studied cladoceran. We here present a first biogeographical assessment of the genus on the Indian subcontinent (Afghanistan, Pakistan, India, Nepal, Bhutan, Bangladesh and Sri Lanka). We collected all pertinent literature and considered nineteen bioclimatic variables along with latitude, longitude, and altitude for statistical analysis of factors governing distribution in space. Significant variables (determined by Kruskal Wallis test) were tested by nonparametric multivariate analysis of variance (PERMANOVA) to clarify whether Daphnia species had specific environmental requirements. Canonical correspondence analysis was used to understand how environmental variables affected distribution.  Eight Daphnia (Ctenodaphnia) and 4 Daphnia s.str. occurred at 100 different localities. The variables temperature, altitude and latitude differed among species and so did their bio-climatic requirements. Daphnia distribution responded positively to altitude and negatively to a decrease in latitude and temperature.