Oj saturation (7o) 



This can be attributed to the combined effects of compaction, greater moisture content, aiid the 

 increased O2 demand of heterotrophic activity. 



The production of plant material was measured by clipping as accumulated production over 

 2 July, 29 July, and 28 August sampling dates. In the track depression, production was greater 

 than that of control on plot 306, less on plot 303, and about the same as that of control on plot 305. 

 However, plant density was much less in the track than on the control locations, but the plants in 

 the track appeared to be much larger. On the average, production was greatest on the mound and 

 second greatest on the bank; and, in spite of lower plant densities, the track depressions had 

 slightly greater primary production than the controls. 



On 27 August 1970, four sod cores, each 15.2 cm in diameter, were removed for arthropod 

 analysis from each of three stations along the weasel track but not in the plots. Station 1 

 corresponded to the depression of plot 305; the site was under standing water for the entire season 

 and vegetation was sparse. Station 2, in an area of the track showing less subsidence, correspond- 

 ed to the depression of plot 303. Station 3 was on the mound adjacent to station 2, and correspond- 

 ed to the mound of plot 303. 



Soil arthropod densities recorded at these stations are given in Table XXVIII. 



Table XXVIII. Soil arthropod densities. 



These differences are striking and suggest that the flooded portion of the track was acting 

 more like a small pond from the standpoint of the micro-arthropods. Station 2 resembled an 

 ephemeral pond and was intermediate between an aquatic and terrestrial system. 



Revegetation which occurs in the tracks is dependent on the types of species adjacent to the 

 disturbed area. This is evidenced by an examination of the species which are found to inhabit 

 these tracks and by a comparison with the adjacent available flora. Revegetation occurs primarily 

 by vegetative reproduction as can be seen when the root systems are exposed. Rhizomes from the 

 track can aU be traced to "parent" plants alongside the track. Species which appear to be most 

 successful in revegetating are Dupontia fischeri in wet areas (also Arctophila (ulva if parent plants 

 are available in the area), Carex aquatilis and, to a lesser extent, Alopecuriis alpinus in somewhat 

 drier situations. Occasionally, Arctagrostis latilolia invades the track although it as well as 



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