TABLE 7 6 Relation of blotic 

 succession to climatic succession 

 in ponds and bogs. Vertical 

 succession from open water to 

 cjimai forest is taking place in 

 both the pond and the bog, but 

 as the climate gets warmer, there 

 is simultaneously a horijontal 

 succession from the various stages 

 in the bog sere to equivalent stage 

 in the pond sere. 



In some bogs (Gates 1942, Dansereau and Se- 

 gadas-Vianna 1952) the first plant stage may be com- 

 posed of floating vegetation {Ntiphar, Nymphaea. 

 Potaiiwgeton. Spart/aniiini) , but floating vegetation 

 is often absent and the first stage is a sedcjc-mat com- 

 posed of sedges, cottongrass, and buckbean. The 

 rhizomes of the sedges grow out into the water and 

 become so interlaced that they form a floating mat. 

 At the water edge the mat may be very thin, but 

 towards shore it may become as much as a meter 

 thick. Since the mat floats on open water it jars 

 easily, hence the name quaking bog — one must watch 

 liis step that he does not break through. Sphagnum 

 moss is not essential for the formation of a mat, but 

 it invades the mat quickly and helps bind it together. 

 Sphagnum persists into the shrub and bog-forest 

 stages following. Interesting insectivorous species 

 such as the pitcher plant and sundew are common, 

 as are various members of the orchid family. 



The next plant stage is dominated by low shrubs. 

 which encroach on the floating mat. The leatherleaf, 

 bog rosemary, laurels, labrador tea, sweet gale, and 

 cranberries are important species. 



A high shrub stage commonly follows the low 

 shrubs at such time as the mat becomes thicker or 

 grounded. Common shrub species are holly, willow, 

 chokeberry, alders, and dwarf birch. 



The first tree of the bog forest to invade the 

 shrubs is commonly the tamarack, but this species is 

 now less common than formerly because of fire, log- 

 ging, and the depredations of the sawfly larvae 

 Lygaeonematus erichsonii. Black spruce may either 

 invade the shrubs directly or follow the tainarack. 

 Later, the northern white-cedar may become domi- 

 nant and persist for a very long time, but the ultimate 

 fate of the bog, upon addition of upland soil or lower- 

 ing of the water table, is to be covered with the 

 climax forest of the region. 



Animal life 



In bogs that have a large body of open water, or 

 an inflow of water entraining oxygen, and in which 

 the pH is not extreme, invertebrate life comparable to 

 that found in ponds and marshes occurs. True bogs, 

 however, have little oxygen and a low pH, and many 

 pond species do not appear. Mollusks are character- 

 istically absent ; sphaeriids may persist but their shells 

 l^ecome very thin. Bottom organisms in general are 

 poorly represented because of the tenuous physical 

 nature of the substratum. 



Desmids predominate among the phytoplankton, 

 although dinoflagellates, Chlorophyceae, and Myxo- 

 phyceae are common. Rotifers and a variety of Pro- 

 tozoa are the principal zooplankters (Graaf 1957). 



The chief fish found in acid waters in Michigan 

 are the brown bullhead, northern pike, bluegill, yellow 

 perch, and mudminnow (Jewell and Brown 1929). 

 The mudminnow may be found in waters almost de- 

 void of oxygen since it is one of the few species that 

 can live indefinitely by gulping air at the surface. 



Amphibians and reptiles are not characteristic of 

 bogs, although the leopard frog is sometimes numer- 

 ous on the sedge mat of bogs in Minnesota (Marshall 

 and Buell 1955). Marsh birds are few in species and 

 in no bogs do populations approach the magnitudes 

 found in southern marshes. The muskrat and beaver 

 persist into northern Canada. 



In general, the productivity and economic value 

 of bogs is very low compared with ponds and 

 marshes. Liming experiments, calculated to improve 

 productivity, are being made. Calcium combines with 

 the humic colloids which then flocculate and fall to 

 the bottom. This clears the water, light penetrates 

 deeper. pH is raised, and greater algal, zooplankton, 

 and fish growth is induced (Hasler et al. 1951 ). Peat 

 is a special bogs product of importance in northern 



Ponds, marshes, swamps, and bogs 93 



