biomass. While the tundra is not species poa in fungi relative to taiga, it contains fewer active 

 decomposers. Again, all the figures are not available but it seems that the number of active fungal 

 decomposers decreases northward, so that at Prudhoe Bay five fungi account for 58% of isolates. 

 At Barrow five organisms account for 45% of isolates. The alpine tundra site at Eagle Summit, in 

 the midst of a taiga area, has a high number of species but tliree organisms account for 72% of 

 isolates. Based on percent density figures, 53% of the active decomposers at College is accounted 

 for by eleven species. 



The tundra and taiga species lists of fungi are continually growing as new soils are examined. 

 Sixteen species of cryophyllic fungi have been recovered from tundra soils. These organisms will 

 grow well at temperatures erf 2 to 5°C. This summer's work will more than double the list of micr- 

 fungi species recorded for Alaska. Many of the genera are also new records for these latitudes. 

 Information on the occurrence, association and distribution of fungi in Alaska will soon be available 

 when figures are finally correlated with study sites and the higher vegetation. 



Soil nutrients 



The availability of soil nutrients and its temporal variation due to surface disturbances is of 

 considerable importance from the standpoint of natural or man-induced revegetation. In order to 

 assess the short-term responses of soils to disturbances, their nutrient statuses were investigated 

 at several sites in the Fairbanks area and Prudhoe Bay. Results of the Prudhoe studies were 

 •briefly discussed in a previous section. The two sites in the Fairbanks area represent character- 

 istics and terrain for the interior. Four plots were established in the lowlands of the Poker-Caribou 

 Creek watershed on a southeast slope consisting of a black spruce bog. Four 6-m-square plots, 

 separated by 6-m buffer strips were established on the same elevation contour. Selected treatments 

 applied to each plot were: control; stripped and tilled; stripped, tiUed and fertilized with 400 lb/acre 

 of 20-10-10 and 8-32-16 fertilizer each. The strippii^ treatment removed all green vegetation including over- 

 story trees, underbrush and surface cryptogams. The tilling treatment involved cultivating the sur- 

 face organic matter with a rake. Fertilizer was broadcast by hand on the plots. Because of limited 

 time and personnel, the treatments were not replicated. Personnel under the supervision of C.S. 

 Slaughter (USA CRREL) assisted in establishing the plots. 



The Fairbanks bog plots were located near the University at College, in a site where pipeline 

 trenching studies had been conducted during the winter of 1968-1969. During trenching operations 

 the surface vegetation was removed exposing the subsoil organic matter layers. Two sampling 

 sites were located in this area: one in an undisturbed paper-birch forest on the edge of the bog and 

 the second in an immediately adjacent stripped area. 



Field soil sampling procedures, processing of samples and analytical nutrient determinations 

 were the same for material collected from the various study areas. Soil saturation extracts were 

 analyzed for nitrate (phenoldisulfonic acid method), phosphate (stannous chloride method) and 

 glucose (glucostat procedure). Results are expressed as milligrams nutrient per gram dry weight 

 of sample at the field moisture content. Sampling and analytical procedures were similar to those 

 utilized at Barrow. 



In general, the concentrations of nutrients at all sampling sites were low and no consistent 

 seasonal trends are evident between disturbed and control samples (Table XLVII). More intensive 

 sample collections over time might disclose trends in nutrient concentrations not evident at this 

 time. Nutrient concentrations were not consistently different between Fairbanks bog-stripped and 

 control plots. The Poker Creek samples also showed no consistent trends in nutrient concentrations 

 during the sampling period. Concentrations of glucose at all sites were generally low. The high 

 glucose concentration in the September 2 Poker Creek control sample may indicate contamination 

 by animal droppings. There is need for more frequent replicated sampling and concurrent acquisi- 

 tion of environmental data such as soil temperature. Although initial responses to the several mani- 

 pulations are not dramatic, cumulative effects over several seasons may prove significant. These 

 observations are being compared with other soil nutrient studies throughout the interia. 



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