a> 

 c 



(0 



(0 



o 

 o 



0) 

 Q. 

 0) 



o 

 E 



(A) Carex pensylvanica 



25-1 □ Before trampling 



■ After trampling 

 20-1 ^ ^ ys3'' 



15- 



(B) Potentilla simplex 



10- 



I 1 



(D) Dryopteris campyloptera 



I 



200 500 25 



Number of Passes 



Figure 31 — Species richness before and after trampling and after 1 year 

 of recovery in four vegetation types in Northi Carolina's Great Smoky Moun- 

 tains. Vertical bars represent 1 standard error above the mean. 



75 



200 



500 



General Appearance 



Obvious changes occurred most rapidly in the Dry- 

 opteris type, dominated by ferns and forbs. Ferns were 

 flattened and shredded after just a few passes. A path 

 was evident after just 25 passes. Virtually all vegeta- 

 tion had been obliterated after 200 passes. In both the 

 Amphicarpa and Potentilla types, paths were evident 

 after 75 passes; however, damage was more apparent 

 in Amphicarpa. In Carex, a path was obvious only on 

 the 200- and 500-pass lanes. Evidence of trampling 

 disturbance declined over the year of recovery in all 

 four vegetation tjrpes. Recovery was most pronoiuiced 

 in Potentilla, where impact was barely evident, even 

 on the most heavily trampled lanes. In the three other 

 types, paths were still evident on the 500-pass lanes. 



Summary Indicators 



The most resistant type was clearly Carex, which 

 had a relatively sparse cover dominated by the tall 

 stoloniferous sedge, Carex pensylvanica (table 24). 

 Because the sedge was resistant, cover was not lost, 

 species composition was not changed, and paths were 



not developed as rapidly as in other types. Several 

 associated species were relatively fragile; consequently, 

 species richness declined more rapidly than in some 

 of the other types. In comparison to the other study 

 areas, differences in the relative resistance of each 

 type to cover loss and height reduction are less pro- 

 nounced. Dryopteris was the least resistant type to 

 all changes other than reduction in species richness. 

 In terms of resistance, Potentilla and Amphicarpa 

 were intermediate in response, although Potentilla 

 was clearly more resistant than Amphicarpa. 



All four vegetation types were quite resilient. Re- 

 covery was probably most pronounced in Potentilla, 

 with little evidence of disturbance 1 year after tram- 

 pling. Dryopteris recovered substantially as well. 

 However, recovery of vegetation rooted in the tram- 

 pUng lanes was not as pronounced as measurements 

 suggest. Relative cover and height would be much 

 lower if only vegetation rooted in the tramphng lanes 

 was considered. The least resihent type was probably 

 Carex, the type that was most resistant. Carex cover 

 increased little during the year following trampling. 

 The type that showed the impact of trampling the 

 most a year later was Amphicarpa. 



42 



