1

Abstract—A standard protocol for conducting experimental

trampling studies was developed by Cole and Bayfield (1993).

Two variables that were not standardized in that protocol are

the type of shoe worn by tramplers and the weight of tramplers. In a study conducted in four different vegetation types,

tramplers wearing lug-soled boots caused significantly more

immediate vegetation cover loss than tramplers wearing running shoes. Shoe type had no significant effect on cover loss 1

year after trampling or on vegetation height. Heavier tramplers caused a significantly greater reduction in vegetation

height than lighter tramplers, both immediately after trampling and 1 year later. Trampler weight had no significant effect on vegetation cover loss. This suggests that it is important

to standardize shoe type and trampler weight in trampling experiments.

Keywords: experimental methods, recreation, vegetation

Our understanding of the effects of recreational

trampling on natural vegetation has been advanced

greatly by the application of experimental research designs. Such studies have particularly improved our understanding of the relationship between trampling intensity and vegetation response and the relative

vulnerability of different plant species, growth forms,

and plant communities. For this latter purpose it

would be helpful to be able to compare the response of

species, growth forms, and communities included in

different studies. The comparability of different studies is highly suspect, however, because each study has

typically used a unique set of experimental procedures.

A recent paper appealed for greater standardization

of experimental trampling studies and detailed a standard protocol developed over several years of trial and

discussion in the United States and the United Kingdom (Cole and Bayfield 1993). Application of that standard protocol in a variety of different ecoregions and

vegetation types has already produced more general

insights into vegetational response to trampling (Cole

1993).

United States

Department

of Agriculture

Forest Service

Intermountain

Research Station

Research Note

INT-RN-425

February 1995

Recreational Trampling

Experiments: Effects of

Trampler Weight and Shoe

Type

David N. Cole

In the discussion of standard trampling treatments,

Cole and Bayfield (1993) stated that their standard

treatment used walkers of moderate weight (75 ± 10

kg), wearing boots with lug soles. However, it was not

clear whether a standard weight and shoe type was

important. This paper presents the results of experiments that assess vegetational response to trampling

by walkers of different weights and wearing different

shoe types. These results can be used to improve the

standardization of trampling experiments.

Study Areas

These trampling experiments were conducted in

one vegetation type in each of four mountainous regions in the U.S.A. The four vegetation types, named

for the most abundant ground cover species, were (1)

Valeriana sitchensis, lush subalpine herb meadows in

the Cascade Mountains of Washington; (2) Vaccinium

scoparium, subalpine coniferous forests with a dwarfshrub ground cover in the Rocky Mountains of Colorado; (3) Maianthemum canadensis, low-elevation

hardwood forests with a herbaceous ground cover in

the White Mountains of New Hampshire; and (4)

Amphicarpa bracteata, low-elevation cove hardwood

forests with a herbaceous ground cover in the Great

Smoky Mountains of North Carolina. More complete

descriptions of these vegetation types can be found in

Cole (1993).

Methods

Details on the layout of the experimental plots, trampling treatments, measurements, and data analysis

can be found in Cole and Bayfield (1993). The study

was arranged as two 4-by-4-by-2 factorial experiments.

In both experiments, four trampling intensities–25,

75, 200, and 500 passes–were applied in each of the

four vegetation types. Conditions were also monitored

on control plots to evaluate changes over time that

should not be attributed to the trampling treatments.

In both experiments primary interest was in the

David N. Cole is Research Biologist for the Aldo Leopold Wilderness

Research Institute, Missoula, MT.
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Table 1—Analysis of variance of the effect of number of passes, vegetation type, and shoe type on relative

vegetation cover immediately after trampling and 1 year after trampling.

Immediately 1 year

after trampling after trampling

Source of variation df Mean square F Mean square F

Blocks 3 1,050 7.19 ** 5,013 15.28 **

Number of passes 3 18,988 130.05 ** 11,033 33.64 **

Vegetation type 3 7,186 49.22 ** 8,995 27.42 **

Shoe type 1 1,249 8.55 ** 3 0.01

Passes x vegetation 9 532 3.64 ** 1,408 4.29 **

Passes x shoe 3 138 0.95 237 0.72

Vegetation x shoe 3 333 2.28 929 2.83 *

Passes x vegetation x shoe 9 81 0.55 384 1.17

Error 93 146 328

Significance: * £ 0.05; ** £ 0.01.

effects of the third factor–the weight and shoe type of

the trampler. In the first experiment, the effect of shoe

type was assessed by comparing the effects of a 77-kg

trampler (±5 kg) wearing lug-soled boots to the effects

of the same trampler wearing lightweight running

shoes. In the second experiment, the effect of trampler

weight was assessed by comparing the effects of tramplers who weighed 59 ± 5 kg to the effects of tramplers

who weighed 77 ± 5 kg. For this second experiment, all

tramplers wore boots with lug soles. Each experiment

utilized a randomized block design, with four blocks.

The primary measures of vegetation response to

trampling were relative vegetation cover and relative

vegetation height. Both measures express conditions

(vegetation cover and height) after trampling as a proportion of initial conditions, with a correction factor applied to account for changes on control plots. Both relative cover and relative height would be 100 percent in

the absence of change caused by trampling. Therefore,

lower relative cover and relative height values indicate

greater amounts of vegetation loss and height reduction. Relative cover and relative height, immediately

after trampling and 1 year after trampling, were calculated for each treatment. The significance of differences

between shoe types and weights of the trampler was

tested with analysis of variance. Where interactions between main factors were significant, simple effects

were examined in more detail, using the least significant difference test. A significance level of 0.05 was

used for both the analyses of variance and least significant difference tests.

Results

Shoe Type

As reported elsewhere (Cole 1993), relative vegetation cover after trampling varied significantly with

number of passes and with vegetation type (table 1).

The significant variation between blocks within the

same vegetation type further emphasizes the variation

in susceptibility that exists even at the micro-scale.

Differences between shoe types were also significant,

although mean squares were not as great as for number of passes or vegetation type. None of the interactions of other factors with shoe type were statistically

significant. Mean relative cover after trampling was 31

percent when the trampler wore lug-soled boots and 37

percent when the trampler wore running shoes.

One year after trampling, relative vegetation cover

varied significantly with number of passes, vegetation

type, and block, but not with shoe type. The interaction

between vegetation type and shoe type was significant.

In two vegetation types, lug-soled boots caused more

cover loss than running shoes; they caused less cover

loss in the other two types. However, differences were

not statistically significant in any individual vegetation

type. Across all four vegetation types, mean relative

cover 1 year after trampling was 68 percent when the

trampler wore lug-soled boots and 67 percent when the

trampler wore running shoes.

Relative vegetation height immediately after trampling and 1 year after trampling varied significantly

with number of passes, vegetation type, and block.

However, shoe type had no effect on vegetation height

(table 2). Mean relative vegetation height immediately

after trampling was 29 percent when the trampler wore

lug-soled boots and 34 percent when the trampler wore

running shoes. Mean relative height 1 year after trampling was 69 percent when the tram- pler wore lugsoled boots and 72 percent when the trampler wore

running shoes.

Weight of the Trampler

Relative vegetation cover did not vary significantly

with weight of the trampler, either immediately after

trampling or 1 year after trampling (table 3). Immediately after trampling, the interaction between number

of passes and weight of the trampler was significant. At

the lowest trampling intensity–25 passes–the heavier
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trampler caused significantly more vegetation loss than

the lighter trampler. At all other trampling intensities,

however, there was little difference between weights.

Across all four trampling intensities, mean relative

cover after trampling was 31 percent for the 77-kg

trampler and 33 percent for the 59-kg trampler. One

year after trampling, none of the interactions of other

factors with weight of trampler were significant. Mean

relative cover 1 year after trampling was 64 percent for

the 77-kg trampler and 69 percent for the 57-kg trampler.

Relative vegetation height varied significantly with

weight of the trampler, both immediately after trampling and 1 year after trampling (table 4). Immediately

after trampling the interaction between vegetation type

and weight of trampler was significant, although the

mean square associated with the interaction was small

compared to that of the weight factor. The heavier

trampler caused significantly more height reduction

than the lighter trampler in only two of the vegetation

types–the two that were most resistant to height reduction following low trampling intensities. In the

Vaccinium scoparium type, mean relative height was

58 percent with the 77-kg trampler and 75 percent with

the 59-kg trampler. In the Maianthemum canadensis

type, mean relative height was 12 percent with the 77-

kg trampler and 32 percent with the 59-kg trampler. In

the Potentilla simplex type, mean relative height was 9

percent with the 77-kg trampler and 11 percent with

the 59-kg trampler. In the Valeriana sitchensis type,

relative height was 19 percent with both the 77-kg and

59-kg trampler.

One year after trampling, none of the interactions of

other factors with weight of trampler were statistically

significant. The heavier trampler caused more height

reduction than the lighter trampler in all four vegetation types. Across all four types, mean relative height

was 61 percent with the 77-kg trampler and 79 percent

with the 59-kg trampler.

Table 2—Analysis of variance for the effect of number of passes, vegetation type, and shoe type on relative

vegetation height immediately after trampling and 1 year after trampling.

Immediately 1 year

after trampling after trampling

Source of variation df Mean square F Mean square F

Blocks 3 1,939 8.39 ** 3,973 8.49 **

Number of passes 3 5,748 24.88 ** 12,404 26.50 **

Vegetation type 3 19,333 83.69 ** 5,858 12.52 **

Shoe type 1 571 2.47 172 0.37

Passes x vegetation 9 247 1.07 896 1.91

Passes x shoe 3 127 0.55 146 0.31

Vegetation x shoe 3 888 3.84 * 1,440 3.08 *

Passes x vegetation x shoe 9 448 1.94 210 0.45

Error 93 231 468

Significance: * £ 0.05; ** £ 0.01.

Table 3—Analysis of variance for the effect of number of passes, vegetation type, and weight of trampler on

relative vegetation cover immediately after trampling and 1 year after trampling.

Immediately 1 year

after trampling after trampling

Source of variation df Mean square F Mean square F

Blocks 3 673 8.96 ** 7,755 29.26 **

Number of passes 3 16,948 255.55 ** 9,769 36.86 **

Vegetation type 3 11,747 156.34 ** 8,780 33.13 **

Weight of trampler 1 149 1.98 872 3.29

Passes x vegetation 9 388 5.16 ** 911 3.44 **

Passes x weight 3 256 3.41 * 451 1.70

Vegetation x weight 3 69 0.92 539 2.03

Passes x vegetation x weight 9 41 0.55 152 0.57

Error 93 75 265

Significance: * £ 0.05; ** £ 0.01.
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Discussion and Conclusions

This study corroborates the findings of earlier research that vegetation cover and height are greatly affected by trampling and that the magnitude of response

is strongly influenced by trampling intensity (Liddle

1975). The magnitude of response is also strongly affected by vegetation durability. Different vegetation

types respond differently, as do different blocks–even

those located only a few meters away from each other.

Although effects are less pronounced, the type of shoe

worn by tramplers and the weight of tramplers can have

modest effects on certain types of vegetation response.

The type of shoe worn had more of an effect on vegetation cover loss than on vegetation height reduction.

It also had more of an effect immediately after trampling than 1 year later. The mean vegetation cover loss

caused by trampling with lug-soled boots was 6 percent

greater than that caused by trampling with running

shoes in the four vegetation types examined. One year

after trampling, vegetation cover loss was still evident

but the magnitude of loss did not differ with shoe type.

The weight of the trampler had more of an effect on

vegetation height reduction than on vegetation cover

loss. It had more of an effect 1 year after trampling

than immediately after trampling. Immediately after

trampling, the 77-kg tramplers reduced vegetation

height 9 percent more than lighter (59 kg) tramplers in

the four vegetation types examined. One year after

trampling, the height reduction caused by the heavier

trampler was 18 percent more than that caused by the

lighter trampler.

Experimental trampling studies such as those reported here can help managers plan for recreational

use. Application of standard protocols for such studies

will increase the comparability of results. In addition to

the standard procedures recommended by Cole and

Bayfield (1993), it is important to standardize shoe

type and weight of the trampler. I recommend using

tramplers of moderate weight (as close to 77 kg as possible) wearing boots with lug soles as the standard

treatment. Lighter tramplers can carry packs to increase their weight to the standard.

References

Cole, David N. 1993. Trampling effects on mountain

vegetation in Washington, Colorado, New

Hampshire, and North Carolina. Res. Pap. INT-464.

Ogden, UT: U.S. Department of Agriculture, Forest

Service, Intermountain Research Station. 56 p.

Cole, David N.; Bayfield, Neil G. 1993. Recreational

trampling of vegetation: standard experimental

procedures. Biological Conservation. 63: 209-215.

Liddle, M. J. 1975. A selective review of the ecological

effects of human trampling on natural ecosystems.

Biological Conservation. 7: 17-36.

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Table 4—Analysis of variance for the effect of number of passes, vegetation type, and weight of trampler on

relative vegetation height immediately after trampling and 1 year after trampling.

Immediately 1 year

after trampling after trampling

Source of variation df Mean square F Mean square F

Blocks 3 1,428 6.89 ** 3,042 6.09 **

Number of passes 3 4,707 22.72 ** 11,320 22.64 **

Vegetation type 3 20,567 99.25 ** 3,275 6.55 **

Weight of trampler 1 3,211 15.30 ** 10,457 20.92 **

Passes x vegetation 9 394 1.90 1,272 2.54 *

Passes x weight 3 270 1.30 1,046 2.09

Vegetation x weight 3 815 3.93 * 45 0.09

Passes x vegetation x weight 9 201 0.97 496 0.99

Error 93 207 500

Significance: * £ 0.05; ** £ 0.01.

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national origin, age, religion, sex, or disability, familial status, or political affiliation. Persons believing they have been discriminated against in any Forest Service related activity should write to: Chief, Forest Service, USDA, P.O. Box 96090,

Washington, DC 20090-6090.

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Ogden, UT 84401