NATURAL AREAS AND REGIONS 



285 



rocks. There are many beautiful lakes 

 throughout the glaciated areas. The 

 greater part of the state was formerly 

 covered by coniferous forests; portions 

 of the southern half by oak and maple, 

 interspersed with swamps and prairies. 

 The mean annual temperatures now vary 

 from 39° in the north to over 47° in the 

 south, the average being 43°. The 

 mean annual precipitation is about 36 

 in. ranging from 28 to 44 in. in various 

 parts of the state. 



In days gone by the beaver, Virginia 

 deer, timber wolf, wolverine, red squir- 

 rel, porcupine, black bear, ruffed grouse, 

 barred owl, and fox snake were common 

 in the northern coniferous forests. 

 Further south, the hardwoods were 

 populated by Virginia deer, gray and fox 

 squirrels, chipmunk, cottontail rabbit, 

 red fox, etc. The sloughs along the 

 Mississippi and Fox Rivers and the 

 swamps along lakes and rivers through- 

 out the state were resorts for water fowl, 

 mink, and muskrat. In the sandy areas 

 as far north as the middle of the state 

 lizards ran about among cactus and other 

 xerophytic plants. On the prairies in 

 the southwest were herds of bison, with 

 prairie chickens and ground-squirrels. 

 In northern waters the muskellonge and 

 lake trout were more or less characteris- 

 tic fishes. The mud-puppy (Nectiirus 

 maculosus) and painted turtle {Chrys- 

 emys marginata bellii) ranged through- 

 out the state. For further information 

 on animals see accounts of Minnesota, 

 Illinois, and Michigan. 



The northern coniferous forests have 

 been largely cut and burned over, but 

 retain many of their original character- 

 istics and in some places are primeval. 

 159,000 acres of this land, which is 

 chiefly in Oneida and Vilas Counties, 

 is under state supervision as forest 

 reserves. Here Virginia deer, and in 

 some places even beaver, are quite 

 common. Away from settlements the 

 porcupine and black bear are found. 

 Ruffed grouse are protected and in 

 many localities are common. In the 

 south the hardwood forests have gener- 

 ally been replaced by farms and dairies. 



The cottontail rabbit, ground-squirrel, 

 and quail remain fairly common. The 

 opossum is rare in the southeastern 

 corner of the state, and the wood turtle 

 occurs in sandy areas in the west. The 

 cardinal is rather uncommon on the 

 southern border, except on the ]\Iissis- 

 sippi bottoms, where it occurs in con- 

 siderable numbers. 



The lakes in the south have been more 

 or less "fished out," though carp, 

 buffalo, and other fishes are usually 

 abundant. The Northern lakes con- 

 tinue to furnish many game fishes, such 

 as pickerel, bass, and sunfish. Certain 

 of the deeper inland lakes and the Great 

 Lakes contain ciscoes. The rock stur- 

 geon is very rare but the little hackle- 

 back continues to flourish in the Missis- 

 sippi and certain of its tributaries. 



Mollusca 



It has been observed that ecologically 

 the fresh water moUuscan fauna is 

 divisible into groups which contain 

 characteristic species or varieties. 

 Thus, the lakes have one assemblage 

 of species; the large rivers, as the 

 Mississippi, another; the medium sized 

 rivers, as the Wisconsin and St. Croix, 

 another; the very small rivers, as the 

 Fox and Red Cedar in Wisconsin, 

 another, while the small swales and pools 

 have still another. In most cases, 

 species inhabiting several of these 

 diverse habitats differ varietally and 

 the general character of a stream may be 

 predicted by the form of a species which 

 has been collected from it. This appears 

 to be a law of ecology which has been 

 observed in several places, as in Ohio, 

 Kentucky, Wisconsin, Michigan, Illi- 

 nois, and Indiana. It is probably wide- 

 spread, and when other localities are 

 carefully studied it may perhaps be 

 found to apply universall}'. The Mol- 

 lusca are admirably adapted to reflect 

 the character of the environment, but 

 little attempt has been made in most 

 states to study the moUusk fauna from 

 this standpoint. Most of the published 

 lists are distinctly systematic. A full 

 discussion of this subject will be found 



