Monitoring visitor capacity for Isle au Haut, Acadia National Park, 2015

Jacobi, Charles; Seymour, Abby; Dillon, Kristin; Richardson, Alison

From official executive summary: "The visitor experience standard outlined in the Visitor Use Management Plan for the Isle au Haut District allows ten percent of the days in July and August (six days) to exceed a 6-groups per day encounter standard for hikers. Based on a simulation model of visitor use, this 6-group standard should be equivalent to about 128 visitors per day. If the group encounter standard is violated, NPS management actions will be needed to achieve the intent of P.L. 97-335 to manage visitor use under a 'strictly limited' carrying capacity to protect park resources and the quality of the visitor experience. In July and August 2015 surveys were administered to visitors at Duck Harbor to measure trail encounters. As usual, Isle au Haut rangers collected daily visitor use data using established methods. Visitors to Isle au Haut encountered an average of 4 other groups out hiking, which is well below the daily group encounter standard of 6. When asked, they also reported overwhelmingly they do not feel crowded. However, there were 16 days with more than 128 visitors on Isle au Haut, which far exceeds the 6 days per season delineated by the visitor experience standard. These high counts can be attributed to visitors from Private Boats and from Town, and to a much lesser extent, from Commercial Boats. A likely reason for these conflicting results is that visitor’s temporal and spatial use of Isle au Haut trails sufficiently disperses use to reduce the number of encounters for most visitors. It is also possible there were duplicate counts, or the counting methodology overcounts visitors, but this seems less likely. We believe the encounter metric should be given greater weight than the number of visitors counted. Coupled with the fact that the vast majority of visitors did not feel crowded, we conclude that intent of P.L. 97-335 and the goals of the Visitor Use Management Plan were met. Based on these results we offer the following recommendations: - Continue the admittedly difficult-to-obtain visitor count methods, tightening them up wherever possible; - Conduct visitor surveys again in 2018, making a better effort to representatively sample visitors from Town and Private Boats; - Set a group size limit for all groups (commercial, noncommercial, educational etc.) for trails at Isle au Haut. Finally, we note here that we expect to repeat the resource assessment for trails (Marion 2006) in 2016 to see if conditions have changed after 14 years of visitation. If conditions have degraded, we should revisit the 128-person limit because previous research demonstrated a direct relationship between the level of use and trail width and depth."

Monitoring visitor capacity for Isle au Haut, Acadia National Park, 2015

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