THE AUTHOR 



DAVID N. COLE is a research scientist with Systems 

 for Environmental Management, P.O. Box 8868, 

 Missoula, MT. He is working cooperatively with the 

 Intermountain Station's Wilderness Management 

 Research Work Unit at the Forestry Sciences Labora- 

 tory on the University of Montana campus, Missoula. 

 Dr. Cole received his B.A. degree in geography from 

 the University of California, Berkeley, in 1972. He 

 received his Ph.D., also in geography, from the Univer- 

 sity of Oregon in 1977. He has written several papers 

 on the ecological effects of wilderness recreation. 



ACKNOWLEDGMENTS 



I am grateful to many people for help on this pro- 

 ject. Robert Christian, Susan Kerns, Jeffrey Marion, 

 and Margaret Petersen endured the tedium of tramp- 

 ling. Margaret Petersen provided computer assistance. 

 Peter Stickney confirmed species identifications for 

 many of the more difficult plants. Scott Beckett dug 

 and described the soil profiles. 



RESEARCH SUMMARY 



This study examined the response of six vegetation 

 types in western Montana to experimental trampling. 

 The types selected were representative of those most 

 frequently used recreationally in the neighboring Bob 

 Marshall Wilderness: the Abies lasiocarpa/Clintonia 

 uniflora (subalpine fir/queencup beadlily), Abies 

 lasiocarpa/Clintonia uniflora-Vaccinium caespitosum 

 phase (subalpine fir/queencup beadlily-dwarf huckle- 

 berry), Abies lasiocarpa/Vaccinium caespitosum (sub- 

 alpine fir/dwarf huckleberry), Abies lasiocarpa/ 

 Xerophyllum tenax (subalpine fir/beargrass), 

 Pseudotsuga menziesii/Symphoricarpos albus 

 (Douglas-fir/snowberry), and Festuca scabrella-F. 

 idahoensis (rough fescue-Idaho fescue) habitat types. 

 Results are compared with findings from similar ex- 

 periments in other vegetation types. 



All of the forested habitat types showed a curvi- 

 linear relationship between amount of trampling and 

 loss of vegetation cover, loss of plant species, and soil 

 compaction. The effect of any incremental increase in 

 amount of trampling decreases as trampling intensity 

 increases. This indicates that trampling damage will 

 generally be minimized when concentrated in space 

 rather than dispersed over large areas. The Abies 

 lasiocarpa/Xerophyllum tenax habitat type was the 

 most resistant forest type studied, suggesting that it 

 would be worthwhile encouraging campers to select 

 sites in this type. 



The grassland proved to be much more resistant to 

 vegetation loss than any of the forested types. Here 

 no significant cover loss occurred until after a total of 

 1,600 trampling passes had been administered. In such 

 a resistant vegetation type, dispersal of use may be 

 advantageous. 



In contrast to vegetation loss and soil compaction, 

 trampling intensities had to be very high before much 

 bare mineral soil was exposed. The habitat with the 

 thickest organic horizons {Abies lasiocarpa/Clintonia 

 uniflora) experienced the least soil exposure. If heavy 

 enough to kill most vegetation, use should be directed 

 to sites with thick organic horizons. 



Managers of wildernesses and other dispersed 

 recreation areas with similar vegetation can utilize 

 these data to estimate the effects of various use 

 levels. It was possible, for example, to estimate the 

 amount of use that sites in these habitat types could 

 receive and still maintain 50 percent vegetation cover 

 and experience mineral soil exposure of no more than 

 5 percent. For a party of three backpackers, these fre- 

 quencies range from no use in Abies lasiocarpa/ 

 Clintonia uniflora to 5 to 8 nights in Abies 

 lasiocarpa/Xeroptiyllum tenax, and 10 to 15 nights in 

 Festuca scabrella-F. idahoensis. These latter two are 

 some of the most resistant natural vegetation types 

 ever studied; use frequenci'es for vegetation types 

 studied elsewhere can be estimated, with caution, 

 from several tables that compare the resistance of 

 types studied here to types studied elsewhere. 



The resistance of the major plant species on these 

 sites is assessed. This information can also be used 

 to evaluate the relative durability of alternative recrea- 

 tion sites. 



CONTENTS 



Page 



Introduction i 



Previous Studies i 



Relation Between Amount of Trampling and 



Amount of Vegetation Loss 3 



Relative Resistance of Different Plant 



Community Types 4 



Relative Resistance of Different Growth Forms . . 4 

 Effects of Frequency and Timing of Trampling 



on Vegetation Loss 5 



Western Montana Study Area g 



Field Techniques 11 



Effects of Trampling on Vegetation Cover 12 



Effect of Trampling Frequency 12 



Effect of Trampling Intensity 13 



Relative Resistance of Different Habitat Types . . 16 

 Effect of Local Variations in Species 



Composition ts 



Effect of Trampling on Number of Plant Species ... 20 



Response of Individual Species to Trampling 21 



Effect of Trampling on Mineral Soil Exposure 28 



Effect of Trampling on Soil Compaction 29 



Conclusions and Management Implications 31 



References 34 



Appendix 1:Soil Profiles 36 



Appendix 2: Mean Cover and Frequency Values .... 39 



