COURTESY OF YU-FAI LEUNG 2011

Figure 1. View of Yosemite Falls from Cook’s Meadow, Yosemite Valley.

Open landscapes provide vital habitats for a diverse array of flora and fauna and serve a number of important hydrologic functions. In addition to their ecological importance, open landscapes provide space for varied human activities. While different types of open landscapes—for example, meadows, dunes, and beaches—serve different ecological and social functions, key shared characteristics include high visibility, walkability, and aesthetic appeal (Falk and Balling 2010; Magill 1992) (fig. 1, above). The National Park Service (NPS) actively manages for both resource protection and visitor experience, yet open landscapes are still subject to external and internal threats, including climate change, altered hydrologic regimes, encroaching development, and intense visitor use.

Proliferation of visitor-created informal trails is a common type of impact associated with open landscapes. Informal trails, also called social or unauthorized trails, are visually identifiable pathways that fall outside of the park’s formal trail system (Leung et al. 2002). Informal trails are often inappropriately located with respect to resource protection objectives, can cause landscape and habitat fragmentation, and can negatively affect visitor experience by visually scarring the landscape (Leung et al. 2011; Marion et al. 2006; Wimpey and Marion 2011).

Effective management of open landscapes, especially those subject to high use with significant informal trail presence, requires an understanding of visitor use and its spatial and temporal patterns. Quantitative information on the location and intensity of visitor use can alert managers to potential resource impacts or areas prone to crowding or other experiential impacts. This need motivated development of the monitoring methodology presented in this study. Many methods for monitoring visitor use in parks and protected areas are designed for static locations like entrance stations or trailheads. Human observers and on-site automated counters are common methods to document visitor numbers at these types of locations and are important tools for estimating use numbers (Cessford and Muhar 2003; Pettebone et al. 2010). However, open landscapes, like meadows, present special monitoring challenges because there are often multiple points of access and limited or no infrastructure to confine visitor use, reducing the effectiveness of some visitor use monitoring methods. Additionally, the inclusion of spatially explicit visitor data can lead to a deeper understanding of the relationship between visitor use and resource impacts when integrated with biophysical data like vegetation condition or water quality.