Preliminary results of a classification of fifty-one selected northeastern Wisconsin Lakes (USA) using indicator diatom species

Diatom species lists were generated for 51 lakes in northeastern Wisconsin, and then classified by two-way indicator species analysis (TWINSPAN). The lakes were initially divided into two main groupings: Group I lakes which were alkaline lakes of moderate to high productivity, and Group II lakes which were acid lakes of low productivity. Group I lakes were further divided into two subgroupings, and four levels. In total, twelve indicator diatom species were recognized during the TWINSPAN lake classification, these were: Achnanthes exigua Grun., A. lanceolata var. dubia Grun., Amphora ovalis var. Affinis (Kütz.) V.H. ex Det., A. perpusilla (Grun.) Grun., Cymbella cistula (Ehrenb.) Kirch., Diploneis elliptica (Kütz.) Cl., Eunotia pectinalis (O.F. Mull.) Rabh., Fragilaria vaucheriae (Kütz.) Peters., Frustulia rhomboides var. crassinervia (Bréb. ex W. Sm.) Ross, Navicula capitata Ehrenb., N. decussis Østr., and N. scutelloides W.Sm. ex Gregory.