Identification of Freshwater Zooplankton Functional Groups Based on the Functional Traits of Species

Information on the functional traits of the most widespread species of freshwater zooplankton (Rotifera, Cladocera, and Copepoda) in European Russia was collected and analyzed. Our database includes 355 species described by 4 traits, namely: maximum body length, trophic group, feeding type, and movement type. Cluster analysis based on Gower's functional distances shows that freshwater zooplankton can be classified into 19 groups with different ecological roles. The characteristics of each identified functional group are presented. We believe it to be fundamentally important to build a unified classification using all available data and applicable characters for all three main taxonomic groups of zooplankton. Comparison with the existing ecological zooplankton classification proposed by Yu. S. Chuikov has demonstrated a number of advantages of our approach. Several ecological groups in Yu. S. Chuikov’s classification are represented by more fractional categories in our classification. Our system of functional groups can be used in studies of the structure of zooplanktocoenoses based on direct cluster analysis and ordination or based on functional distances between samples. To calculate the functional similarity between species, one can use our database of features, which is contained in the Appendix. Analysis based on functional groups gives a better unerstanding of the structure of a community than traditional ordination, which takes into account only the taxonomic affiliation of species. The approach used for functional group identification can be useful in assessing functional diversity and identifying patterns of freshwater zooplanktocoenoses dynamics. The database of functional signs of zooplankton can be used to check the relationship of functional signs with environmental factors.