204 ENTOMOLOGICAL NEWS THE MAYFLIES (EPHEMEROPTERA) OF CONNECTICUT: AN INITIAL FAUNAL SURVEY 1 Steven K. Burian^, Andrew F. Bednarik^ ABSTRACT: Mayflies from 80 sites across Connecticut were studied. A list of 109 species, including 34 new State records, was compiled. Two-way Indicator Species Analysis (TSA) was used to investigate block structure in the overall species data matrix. Site classes produced at suc-cessive division levels in repeated TSA runs showed no discernible stable geographic trends. Sim-ilarities among sites within a class and variation between classes resulted from differences in attributes of aquatic habitat structure that are not constrained within the context of ecoregions/sub-regions proposed for Connecticut. Within New England, Connecticut represents a comparatively small area (13,183.1 km 2 ), but has the potential for a diverse mayfly fauna. Southernmost of the New England States and located directly east of the Hudson River drainage, Connecticut has a range of climate and habitat types typical of areas much further north and south. Recently, Griffith et al. (1993) recognized two broad ecoregions and several subregions in Connecticut (Fig. 1). Throughout these zones aquatic habitats suitable for mayflies are common. Lotic habitats range from large deep rivers to first order streams and spring brooks. Lentic habitats vary from large lakes to small glacially formed ponds and temporary flood plain pools. Connecticut mayfly populations are routinely sampled by environmental agencies for purposes of monitoring water quality. However, these groups have made little effort to identify species and currently there is no species list available. Further, little is known about the distribution of species with regards to landscape patterns. Some site specific data are available from the Con-necticut Department of Environmental Protection, but are biased toward lotic habitats with coarse, poorly sorted substrates. This study is the first attempt to catalog the occurrence of mayfly species in Connecticut and to analyze species assemblages. Species recorded in this study will be entered into a CIS dBase that will be developed into a computerized atlas for mayflies of New England and Atlantic Canada. HISTORICAL OVERVIEW The earliest list of mayflies from Connecticut appears in Britton's (1920) 1 Received September 22, 1993. Accepted March 10. 1994. -Dept. of Biology, Southern Connecticut State University, 501 Crescent Sir ., New Haven, CT 06515 3 8 Birchwood Road, Seymour, CT 06483 ENT. NEWS 105(4): 204-216, September & October 1994
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