Hawkins, Charles P. 1984. Substrate associations and longitudinal distributions in species of Ephemerellidae (Ephemeroptera: Insecta) from western Oregon. Freshwater Invertebrate Biology. 3(4): 181-188.
Substrate associations and longitudinal distributions are described for 12 species ofEphemerellidae. Habitat specialization seems to have been a major means of adaptive radiationwithin this family. All species showed restrictive use of available habitats: sand-gravel, cobble,boulder, or moss. Patterns of longitudinal distribution may be, in part, a consequence of thespecificity that species show for different substrates.
Mayflies in the family Ephemerellidae are often important and conspicuous membersof stream communities. Eighty species in eight genera are currently recognized in NorthAmerica. Thirty-two species occur in the western United States and Canada, 24 of whichoccur in Oregon. Although the taxonomy of species in this family has been well studied(Allen 1980; Edmunds et al. 1976), relatively little quantitative information exists bywhich to compare ecological differences among species.
The purpose of this study was to I) describe patterns of habitat use among 12 speciesoccurring in a single drainage basin and 2) examine whether habitat use may explain, inpart, distribution patterns along a river continuum.