Table 3 — Analysis of variance and multiple comparisons for relative cover after trampling and after 1 year 

 of recovery in Washington's Cascade [fountains 



Source 





After trampling 







After 1 year 





df 



F 



P 



df 



F 



p 



Number of passes 



3 



49.4 



0.0001 



3 



10.7 



0.0001 



Vegetation type 



3 



91.2 



.0001 



3 



18.1 



.0001 



Interaction 



8 



2.5 



.02 



8 



1.3 



.28 





Significantly different treatments 









Number of passes 





25,75>200>500 







25,75>500 





Vegetation types'' 





C,PA>PH>VA 







C,VA>PA,PH 





^Vegetation types: C = Carex, PA = Pachistima, PH = Phyllodoce, VA = Valeriana. 



Calculations of relative vegetation cover are a con- 

 venient way to compare changes in vegetation cover 

 after trampling and after a recovery period. The re- 

 duction of vegetation cover immediately after tram- 

 pling differed significantly both with the amount of 

 trampling and the vegetation type (table 3). The in- 

 teraction between these two main effects (amount of 

 trampling and vegetation type) was also significant, 

 but the magnitude of this interaction was relatively 

 small. After the year of recovery, relative cover still 



differed significantly between trampling intensities 

 and vegetation types. The magnitude of differences 

 had declined, however, and the interaction between 

 these two main effects was no longer significant. 



With only one exception, relative cover declined 

 with each successive increase in the number of passes 

 (fig. 2). The exception was in the Carex vegetation 

 type, where relative cover was 100 percent even after 

 trampling intensity reached 75 passes. 



(A) Pachistima myrsinites 



(B) Carex nigricans 



C 



o 



(D 



a 



o 

 > 

 o 

 o 



c 

 o 



100 

 80 

 60 

 40 

 201- 



1 year after trampling 

 — After trampling 



j_ 



1 



100 200 300 400 

 Phyllodoce empetriformis 



500 



100 200 300 400 500 600 

 Valeriana sitchensis 



700 



100 200 300 400 500 100 200 



Number of Passes 



300 400 



500 



Figure 2 — Relative vegetation cover after trampling and after 1 year of recov- 

 ery in four vegetation types in Wasfiington's Cascade Mountains. Vertical bars 

 represent 1 standard error above and below the mean. 



6 



