The Microflora 273 



a shift in the enzymatic potential to utilize specific substrate constituents 

 (Chapter 9) and compounds of larger molecular weight are degraded less 

 readily. 



Temporal Distribution and Productivity 



Temporal patterns of decomposer biomass indicate the overall pro- 

 ductivity of microflora populations and some effects of environmental 

 factors. Comparison of these patterns among different microtopo- 

 graphic units provides a series of examples of the interactive effects of 

 temperature and moisture. 



Fungi in Standing Dead Vegetation and Litter 



In wet meadows, fungi in both the litter and upper 1 cm of soil show 

 a rapid early-season increase in density at the same time that fungi in 

 standing dead are decreasing (Figure 8-5). The high amounts of moisture 

 at runoff rapidly leach the standing dead substrate and enrich the litter 

 and upper soil layers. 



Seasonal patterns of fungal density in standing dead vary among mi- 

 crotopographic units largely as a function of moisture. The summer of 



5!6000| 1 r 



o 



—o— Litter 

 --^-Standing Dead 

 --•"Soi 



20 

 Jul 



^- -^V 



I I I I I 



ID 20 

 Aug 



10 20 



Sep 



FIGURE 8-5. The seasonal progression of fungal density in 

 standing dead vegetation, plant litter and the I- to 2-cm soil 

 depth in wet meadows, 1973. (After Flanagan, unpubl., and 

 Laursen 1975.) 



