March, 1963 



Larimore & Smith: Fishes of Champaign County 



313 



above neutral, most of the readings rang- 

 ing from 7.2 to 7.8. The amount of dis- 

 solved oxygen varies from supersaturation 

 in well-aerated riffle areas to less than 1 

 p.p.m. in highly polluted waters and in 

 stagnant pools when the stream flow is 

 discontinuous. 



Much of the natural aquatic vegetation 

 in Champaign County streams may have 

 been eliminated early in this century 

 through dredging, pollution, and other 

 man-induced alterations. The remaining 

 vegetation is limited in distribution by 

 the generally high turbidity of the streams. 

 Baker (1922) illustrated many of the 

 stream habitats along the Salt Fork as 

 they appeared in 1919 and 1920. Except 

 for a large patch (which no longer 

 exists) of yellow water lillies, Nuphar 

 advena, northeast of Sidney, the vegeta- 

 tion seen in his photographs is similar to 

 that found at present. Moreover, his de- 

 scription of the aquatic vegetation in- 

 cludes essentially the same species that 

 now occur in the area. 



Thompson & Hunt listed the common 

 coarse aquatic plants that they observed. 

 Their list includes most of the present 

 vegetation. They listed four species of 

 Fotamogeton that we did not find as- 

 sociated with the flowing waters of the 

 county ; however, we observed another spe- 

 cies of Fotamogeton , believed to be F. 

 foliosus Raiinesque, in a number of 

 streams and found it to be quite common 

 in the upper reaches of Lone Tree Creek 

 near Foosland. The field notes of Thomp- 

 son & Hunt and our observations indicate 

 that aquatic vegetation was more exten- 

 sive in 1928 than it is today. 



Dr. Robert A. Evers, of the Section of 

 Applied Botany and Plant Pathology of 

 the Natural History Survey, examined 

 plants in several collections we made dur- 

 ing the present study. His identifications 

 add the following species to the list pre- 

 sented by Thompson & Hunt: 

 Equiseturn arvense Linnaeus 

 Spartina pect'inata Link 

 Carex cristatella Britton 

 Salix interior Rowlee 

 Rum ex altissimus Wood 

 Rorippa islandica (Oeder) Borbas 

 Lysimachia nummularia Linnaeus 

 Asclepias incarnata Linnaeus 

 Phyla lanceolata (Michaux) Greene 



Lycopus americanus Muhlenberg 

 Eiipatorium perjoliatum Linnaeus 

 Hibiscus militaris Cavanilles 

 These plants are not true aquatics but 

 are characteristically associated with the 

 banks and mud flats along most of the 

 streams. A few true aquatics deserve spe- 

 cial comment. Fotamogeton foliosus has 

 already been mentioned as quite common 

 in part of Lone Tree Creek. Elodea 

 canadensis Michaux occurs in large 

 patches in the polluted West Branch be- 

 tween Urbana and St. Joseph. Dinnthera 

 americana Linnaeus is abundant on the 

 riffles and along the shores of many 

 streams, especially in the Middle Fork. 

 Chara sp. was taken near a seepage spot 

 on a tributary of the Spoon River near 

 Flatville. 



The vegetation we observed in our 

 study included grasses, sedges, ragweeds, 

 milkweeds, docks, and several composites 

 along the small streams as they passed 

 through flat and open farmlands. In some 

 of the reaches of these streams, willows 

 and scrubby growths of a few other de- 

 ciduous trees overhung the water. Tall de- 

 ciduous trees lined the banks of most of 

 the large streams. Especially common were 

 silver maple, American elm, cottonwood, 

 sycamore, and willows. In open areas, 

 where the sunshine reached the water, 

 grew buttonbush, rose mallow, water wil- 

 low, and a few other plants. 



Habitat Types 



Although the general ecological char- 

 acteristics of the streams of Champaign 

 County are rather uniform, each stream 

 contains several distinct habitats. The 

 habitats are determined largely by stream 

 size, stream topography and gradient, soil 

 materials comprising the bottom, and hu- 

 man modification of the stream and its 

 drainage basin. 



Thompson & Hunt (1930:34-9) clas- 

 sified stream habitats according to size of 

 area drained, permanency, depth, width, 

 current, type of substrate, amount of veg- 

 etation and debris, turbidity, and faunal 

 composition. They recognized vernal rivu- 

 lets; kettle holes at mouths of tile drains; 

 oxbow ponds along small streams; per- 

 manent headwater streams; stretches of 

 shallow, sluggish water ; gravelly and 

 sandv riffles and stretches ; rocky rapids 



