Bythotrephes longimanus in the Commonwealth of Independent States: variability, distribution and ecolog

摘要: Bythotrephes is presently extending its distribution to basins throughout Europe and North America. We used long term data (1880–1997) on longimanus in Eurasian waterbodies characterize ecology tolerance different ecological factors. Depending season environmental conditions of the waterbody, B. may undergo cyclomorphosis can exist as two distinct forms ( or cederstroemi). Regional species l. var. balticus, it transcaucasicus, arcticus) have also been described. Occurrence density populations varies across geographical scales, are apparently affected primarily by water temperature salinity. limited regions where ranges between 4 30 ^C, although prefers waters 10 24 °C. tolerates salinity values 0.04 8.0i, though 0.4i. These factors strongly restrict Bythotrephes' warmer more saline Commonwealth Independent States (CIS), particularly southern Russia Kazakhstan. Local abundance abiotic factors, including basin morphometry flushing rate, temperature, oxygen concentration pH, well lake trophic status fish predation. Planktivorous habitat use overlap these groups minimized. Rivers, canals, ephemeral serve important modes dispersal CIS western Europe. Morphological adaptations (e.g. a caudal process, cyclic parthenogenesis, production resting eggs) permit tolerate seasonally inhospitable conditions, assist range extension, minimize