Table 10 — Mean vegetation height (cm) before and after trampling and after 1 year of recovery for four vegetation types in 

 Colorado's Rocky Mountains 



Number of passes 



25 



75 



200 



500 



700 



Trifolium parryi 

 (subalpine meadow) 

 Before trampling 

 After trampling 

 After 1 year 



Kobresia myosuroides 



(alpine turf) 



Before trampling 

 After trampling 

 After 1 year 



Vaccinium scoparium 

 (subalpine forest) 

 Before trampling 

 After trampling 

 After 1 year 



Geranium richardsonii 



(montane forest) 

 Before trampling 

 After trampling 

 After 1 year 



3(+)^ 

 3(+) 

 3(+) 



6(+) 

 6(+) 

 5(1) 



7(1) 

 7(1) 

 7(1) 



18(3) 

 18(3) 

 19(2) 



2(+) 

 2(+) 

 3(+) 



8(1) 

 6(1) 

 7(2) 



20 (4) 

 4(+) 

 13(2) 



3(+) 

 2(+) 

 2(+) 



6(1) 

 4(+) 

 4(+) 



7(1) 

 5(1) 

 6(1) 



20 (3) 

 3(-h) 

 15(2) 



3(+) 

 1 (+) 

 2(+) 



7(1) 

 3(+) 

 4(+) 



7(1) 

 4(1) 

 2(1) 



17(3) 



1 (+) 

 14(2) 



3(+) 

 1 (+) 

 2(+) 



7(1) 

 2(+) 

 3(+) 



7(1) 

 2(1) 



1 (+) 



18(4) 



1 (+) 

 12(2) 



7(+) 

 1 (+) 

 3(+) 



'Values in parentheses are one standard error. A + indicates standard error less than 0.5 cm. 



the recovery is remarkable. The Kobresia lanes recov- 

 ered some, but remained disturbed 1 year after tram- 

 pling. Relative cover on the 500-pass lanes w^as 39 

 percent after trampling and 70 percent 1 year later. 

 Largely because Kobresia was the type that vv^as least 

 disturbed initially, its relative cover 1 year after tram- 

 phng was not significantly different fi-om the Trifolium 

 and Geranium types. The Vaccinium type responded 

 uniquely. Relative cover declined over the year fol- 

 loMdng trampUng. On the 200-pass lanes, for example, 

 relative cover was 51 percent immediately after tram- 

 pling but only 35 percent a year later. Shrubs appeared 

 to have been damaged by trampling, but did not die 

 that svunmer. The dieback the follovmig summer ap- 

 peared to be aggravated by pronounced drought. 



Vegetation Height 



Before trampling, ground cover was tallest in the 

 Geranium type (mean of 19 cm) and shortest in the 

 Trifolium type (mean of 3 cm). Mean height was 7 cm 

 in both the Kobresia and Vaccinium types (table 10). 

 TrampUng reduced vegetation height in all types; 

 however, the rate of decline varied among types. 

 Relative height differed significantly both with the 

 amount of trampling and v^dth the vegetation type. 

 The interaction between these effects was not signifi- 

 cant (table 11). One year after trampling, the effects 

 of the amount of trampling and the vegetation type 

 were still statistically significant, as was the inter- 

 action between the two. 



Table 11 — Analysis of variance and multiple comparisons for relative height after trampling and after 1 year 

 of recovery in Colorado's Rocky Mountains 



Source 





After trampling 







After 1 year 





df 



F 



P 



df 



F 



P 



Number of passes 



3 



27.3 



0.0001 



3 



13.3 



0.0001 



Vegetation type 



3 



59.6 



.0001 



3 



39.8 



.0001 



Interaction 



8 



1.6 



.16 



8 



6.7 



.0001 



Significantly different treatments 



Number of passes 25,75>200,500 25>75>200,500 

 Vegetation types^ V.D>K>G D>G,K,V; G>V 



'Vegetation types: V = Vaccinium, D = Danthonia, K = Kobresia, G = Geranium. 



19 



