Yosemite wilderness visitor travel patterns: implications for trailhead permit quotas

Yosemite National Park uses a trailhead quota system to manage wilderness visitors. Park scientists set user carrying capacities in the 1970s for backcountry zones and trailhead quotas from prevalent travel patterns and a computer simulation model. Limiting how many visitors start daily at a trailhead maintains overnight zone use within capacity if trip characteristics (party size, trip duration, spatiotemporal itinerary adherence) remain similar to the 1970s. Evidence suggests that travel patterns have changed since this system's inception. Data on which the original trailhead quotas were based, and the data on itinerary adherence, are nearly forty years old, and the supposition is that visitor use consists of a larger number of shorter-duration trips. Consequently, travel zone capacities are being exceeded in some zones on many high-use nights. To accurately assess wilderness use and itinerary deviation to develop a contemporary travel simulation model, wilderness trips from 1 May through 30 September 2010 were evaluated in regard to mean party size, trip duration; and spatial and temporal itinerary adherence. Strong evidence of visitor spatiotemporal itinerary deviation was found. Travel patterns suggest more concentrated use of frontcountry adjacent areas, and increased visitor attraction to iconic peaks and service facilities. Multiple visitor use scenarios were simulated and resultant use presented to inform resource managers.