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

Abstract

/ Various types of recreational traffic impact hiking trails uniquely and cause different levels of trail degradation; however, trail head restrictions are applied similarly across all types of packstock. The purpose of this study was to assess the relative physical impact of hikers, llamas, and horses on recreational trails. Horse, llama, and hiker traffic were applied to 56 separate plots on an existing trail at Lubrecht Experimental Forest in western Montana. The traffic was applied to plots at intensities of 250 and 1000 passes along with a no-traffic control under both prewetted and dry trail conditions. Soil erosion potential was assessed by sediment yield and runoff (using a Meeuwig type rainfall simulator), changes in soil bulk density, and changes in soil surface roughness. Soil moisture, slope, and rainfall intensity were recorded as independent variables in order to evaluate the extent that they were held constant by the experimental design. Horse traffic consistently made more sediment available for erosion from trails than llama, hiker, or no traffic when analyzed across wet and dry trail plots and high and low intensity traffic plots. Although total runoff was not significantly affected by trail user, wet trail traffic caused significantly greater runoff than dry trail traffic. Llama traffic caused a significant increase in sediment yield compared to the control, but caused erosion yields not significantly different than hiker traffic. Trail traffic did not increase soil compaction on wet trails. Traffic applied to dry trail plots generally resulted in a significant decrease in soil bulk density compared to the control. Decreased soil bulk density was negatively correlated with increased sediment yield and appeared to result in increased trail roughness for horse traffic compared to hiker or llama traffic. Differences described here between llama and horse traffic indicate that trail managers may want to consider managing packstock llamas independent of horses.KEY WORDS: Recreational impacts; Sediment yield; Trail degradation

Horse Riding in Protected Areas: A Critical Review and Implications for Research and Management

“…Cole (1989) and Newsome et al (2004) also recognised that many of the horse riding impacts were similar to those caused by hikers, except they were more pronounced and occur more rapidly. Liddle (1997), Weaver and Dale (1978) and Deluca et al (1998) all argued that horse riding impacts were quantitatively greater than those caused by hikers. Additionally, factors such as long and steep slopes, high elevation, high rainfall events, unvegetated or unsurfaced slopes, low soil organic matter, poor soil structure, ine texture, impeded iniltration of water and close proximity to streams or groundwater discharge areas all contribute to trail degradation (Newsome et al, 2002a).…”

Trail impact monitoring in Rocky Mountain National Park, USA

“…Pack animals, according to Barros and Pickering (2015), caused more damage than hikers to the alpine meadow and their impacts were apparent at a lower level of use than for hikers. Horse traffic also consistently made more sediment available for erosion from llamas, hikers or no traffic (Deluca at al., 1998). It is also important to notice that horse riding trails can promote exotic plant species, many of which are not native to the area, which may lead to changes in the structure of vegetation communities (Törn et al, 2009).…”

Effects of Stock Use and Backpackers on Water Quality in Wilderness in Sequoia and Kings Canyon National Parks, USA

“…Physical effects may include increased suspended sediment concentrations and turbidity in surface water due to erosion of stream banks, trails, and meadows (Deluca et al 1998). Such increases may reduce water clarity, light available for primary production, function of delicate gill tissue in fish, and physical habitat for aquatic species (Ryan 1991;Rabeni and Smale 1995).…”