Table XLIV. Density {%) figures for major species components in 

 hot-pipe experimental area. 



The Hess Creek study area was another spruce-dominated taiga stand. Here again natural 

 and disturbed sites were compared. A total of 38 species were isolated from the natural area and 

 16 from the perturbed site. There were only 11 shared species. Again, bacterial biomass had in- 

 creased tenfold in the perturbed areas and the soil pH had shifted towards alkalinity though not as 

 sharply as it did at College. Comparable natural and perturbed areas were studied in tundra at 

 Sagwon and Prudhoe Bay. The effects of disturbance followed the same pattern: a decrease in 

 soil acidity, increase in bacterial biomass with concomitant changes in fungal species, density, 

 and biomass. 



At College, Hess Creek, Caribou Mt., and Wiseman, respectively, 80, 38, 30 and 60 species 

 were isolated (Table XLV). Each site had its unique species. These are being compared in 

 species composition and density and correlated with phanerogam and abiotic parameters. In the 

 tundra the number of fungal species does not seem to bear any relationship with the numbers of 

 fungal propagules per gram of soU. The species compositicm in each tundra site is different and 

 density figures for species fluctuate greatly. Mycological differences between litter and soils 

 were exhibited by every study area examined (Table XLVI). Matching species with density figures 

 in the different layers indicates which organisms are most active in the particular zone and provides 

 information on the decomposition gradient within the different soils. 



The Alaskan tundra and taiga soils contain comparable numbers of fungal species. Some of 

 these species are restricted to taiga or tundra but there is appreciable overlap. Significant yeast 

 populations occur only in soils north of the Brooks Range. The number of fungal propagules in 

 taiga soils is highest in the College area, decreasing northward to Wiseman. Numbers of fungal 

 propagules in the tundra soils also show a decrease northward. All figures for biomass (i.e. actual 

 active mycelium in soils) have not yet been calculated; however, during July 1970 fungal biomass 

 was essentially the same in College, Barrow and Prudhoe Bay. These figures for taiga areas do 

 not take litter into account. If this were done then the taiga sites would have much greater fungal 



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