Influence of Llamas, Horses, and Hikers on Soil Erosion from Established Recreation Trails in Western Montana, USA.

The research study illustrates the different impacts of hikers, llamas, and horses on the erosion of recreational trails in western Montana. It demonstrates that the type of traffic on hiking trails leads to varying levels of degradation, with horse traffic causing the most significant soil erosion.

Study Overview

• The study was conducted to understand the different physical influences that hikers, llamas, and horses have on the erosion of recreational trails.
• The research was conducted on 56 separate plots along an established trail in Lubrecht Experimental Forest, western Montana.
• Different traffic intensities were applied to these paths, including 250 and 1000 passes, in addition to a no-traffic control, under both dry and prewetted trail conditions.

Methodology

• To measure the potential for soil erosion, the study utilized several methods, which include assessing the sediment yield and runoff using a Meeuwig type rainfall simulator, changes in soil bulk density, and alterations to the surface roughness of the soil.
• The factors of soil moisture, slope gradient, and the intensity of rainfall were noted as independent variables to evaluate the level of constancy maintained by the experimental design.

Results

• Results showed a consistent increase in the availability of sediment for erosion from trails due to horse traffic compared to llama, hiker, or no traffic. This result was consistent across both wet and dry trail conditions as well as both high and low traffic intensities.
• While the overall runoff was not significantly influenced by the type of trail user, it was noted that wet trail traffic resulted in significantly more runoff than dry trail traffic.
• Llama traffic caused a significant increase in sediment yield compared to the control, but the amounts of soil erosion were not significantly different from the hiker traffic.
• Traffic did not increase soil compaction on wet trails, but traffic on dry trail plots generally resulted in a significant decrease in soil bulk density compared to the control. A decrease in soil bulk density correlated negatively with an increase in sediment yield and seemed to increase trail roughness, specifically for horse traffic as compared to hiker or llama traffic.

Implications

• The differences in trail degradation between llamas and horses suggest that trail management strategies may need to consider managing packstock llamas separately from horses, contrary to the current trend of applying the same rules to all packstock.
• The study highlights the importance of considering the type of recreational traffic on trails to maintain their longevity and to prevent unnecessary degradation.