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NOTROPIS ei FUNDULUS 
HETEROLEPIS LABS — DIAPHANUS 
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FUNDULUS 
NOTTI 
Fig. 9-14—Some species of fishes decimated because drainage of natural lakes, sloughs, and marshes has destr¢ 
many of their habitats. Circles, before 1905; dots, after 1950. 
bowfin, mudminnow, and others, on the other hand, Desiccation During Drought 
may have nearby populations in stream oxbows or Desiccation of stream systems during drov 
pools that can disperse into new bodies of water. periods ranks third in importance and is respons 
However, new artificial lakes are usually populated for the range shrinkage of 12 species. In ret 
by stocked species and minnow-bucket releases. decades the water table has fluctuated more wi 
Drainage has affected fishes for many years and __ than it did before 1930. During severe late sum 
has produced the most dramatic effects by the elimina- — and fall drought, streams that were once permane 
tion of bottomland lakes and sloughs marginal to —_ flowing now dry up, seeps and springs cease to 
all of the large rivers and the prairie swales through- —_ and_ some relatively large rivers temporarily bec 
out the northern half of Illinois. medium-sized or small streams. 
10 
