The Use of Volunteered Geographic Information to Explore Informal Trail Networks in Protected Areas

Volunteered Geographic Information is a form of user-generated content, organized in applications and online platforms which compile information about recreational uses. These data are mostly freely available and seen as alternatives to trail inventories and visitor surveys. VGI is useful in studies on informal trail networks to assess visitor-related impacts which may disturb natural and cultural conditions, affecting local resources and causing landscape fragmentation through large scale processes. The present research explores the use of georeferenced tracks from an outdoor sports website, as an alternative resource to assess the distribution of informal trails, their spatial and temporal use, and related impacts in the Arrabida Nature Park, Portugal. A total of 2495 individual tracks, of the 3923 tracks initially downloaded (28911,254 km) were passing through the study area, with 2100 using the official roads and marked trails, while 395 were using the informal trail network. Hiking and biking are the activities that most use informal trails and the places with the highest intensity of use are located between Vale da Rasca and Aldeia Grande. As for landscape fragmentation, there is a decrease in all management zones, with more than 90% of the change in higher protection areas. The proposed method allowed the provision of important insights regarding how the territory is being used, making it also a valuable and alternative resource to assess the spatial distribution of informal trail networks in protected areas and assess the related fragmentation effects.