March, 1963 Larimore & Smith: Fishes of Champaign County 



335 



Table 10. — Changes (increases or decreases) 

 between surveys (FR=: Forbes & Richardson; 

 TH = Thompson & Hunt; LS = Larimore & 

 Smith) in the number of species of fish in 

 Champaign County drainages. Changes include 

 both the taking of species not previously taken 

 and the failure to retake species previously 

 taken in a drainage. Forbes & Richardson 

 made no collections in the Little Vermilion. 



Drainage 



Kaskaskia 



Middle Fork ..._ 



Sangamon 



Salt Fork 



Embarrass 



Little Vermilion 



Total changes 



Total 

 Changes 



47 

 45 

 44 

 39 

 32 



215 



Thompson & Hunt, a total of 129 changes 

 in distribution occurred in the five drain- 

 age systems considered here. Between 1928 

 and 1959, the greatest number of changes 

 occurred in the Kaskaskia ; the least num- 

 ber of changes occurred in the Little Ver- 

 milion drainage. Within the period be- 

 tween 1928 and 1959, a total of 86 

 changes occurred in the six drainages of 

 the county. For the over-all period of 

 study, approximately 60 years, the greatest 

 number of changes occurred in the Kas- 

 kaskia drainage. 



If changes in the occurrence of fish 

 reflect the amount of modification of a 

 stream and its habitats, it should follow 

 that much greater modification occurred 

 during the first 30 years of this century 

 than during the second 30 years. This 

 assumption is substantiated by the histori- 

 cal record of land use and can be observed 

 by noting, in table 10, the interval when 

 the greatest changes in species composition 

 occurred. It should also follow that the 

 most extensive changes in land use early 

 in this century were in the Middle Fork 

 and Sangamon basins and, after 1928, in 

 the Kaskaskia and Salt Fork basins. The 

 small amount of change in the Little Ver- 

 milion is probably due to its small size and 

 comparatively small number of habitats; 

 only the extreme headwaters of this drain- 

 age are in Champaign County. 



ECOLOGICAL ASSOCIATIONS 



Ecological associations can be drawn 

 between a species of fish and various en- 



vironmental factors comprising its habitat, 

 or between a species of fish and other 

 species of fishes with which it is found. 

 However, a clear separation of the influ- 

 ences of the physical environment from 

 those exerted by fishes is often difl^cult or 

 impossible. 



Species Associated With Various 

 Stream Habitats 



The stream habitats defined in table 4 

 on the basis of water velocity, depth, and 

 area of drainage basin contained fish popu- 

 lations characteristic of each. As shown in 

 the tabulations below, some species taken 

 in the Champaign County surveys were 

 limited in their occurrence to a specific 

 habitat, whereas others were more gen- 

 erally distributed. Our assignment of a 

 particular species to a particular habitat 

 was complicated by seasonal changes in 

 fish distribution, differences in distribution 

 of young and adult fish, and lack of uni- 

 formity throughout each habitat. 



Species of Rivulets 

 and Small Creeks 



Etheostoma spectabile 

 Cornpostoma anomalum 

 Se mo til us atroniaculatus 

 Fundiilus notatus 

 Pimephales notatus 

 Erimyzon oblongus, young 

 Catostomus commersoni, young 

 Lepomis cyanellus, young 

 Ictalurus uatalis, young 

 Ictalurus rnelaSj young 



Species of Large Creeks 



Riflles: sand and fine gravel 



Ericymba buccata 



Etheostoma spectabile 



Notropis dorsalis 



Campostoma anomalum 



Phenacobius mirabilis 

 Riffles: gravel and rubble 



Etheostoma caeruleum 



Etheostoma blennioides 



Etheostoma fiabellare 

 Pools: shallow, moderate current 



Notropis chrysocephalus 



Hybopsis biguttata 



Semotilus atromaculatus 



Catostomus commersoni 



Notropis stramineus 



Notropis spilopterus 



