Impacts of rock climbing on avian cliff communities in Boulder, CO
Cliff ecosystems support high levels of biodiversity and serve as refuges for many organisms, including birds. Until recently, cliffs have been mostly undisturbed environments because they are difficult to access, but the increased popularity of rock climbing could have novel impacts on these ecosystems. Boulder County Colorado is diverse in its landscapes and is characterized by unique formations like the Flatirons, making it a haven for premier rock climbing. Boulder Open Space and Mountain Parks support particularly high numbers of both wildlife and recreationists, creating a need for attentive and sensitive management. This project is assessing how rock climbing impacts the productivity, behavior and/or habitat resources of bird species that use cliffs in Boulder, Colorado. We are collecting data on the number and type of bird species at paired sets of cliffs with high and low climbing activity. We are quantifying the space use and behavior of all birds, as well as the number of people present at the sites and their activity and location. In order to assess the effects of climbing on whole cliff communities, surveys of vegetation and insects will be conducted at a subset of the paired sites.
Pilot studies suggest that while climbers do not decrease avian abundance, their presence may disturb birds. A difference in avian behavior was observed between cliffs with and without climbers. When climbers were absent, birds engaged in a wide variety of activities. When climbers were present, birds were either perching or flying. They did not forage, call, sing, or visit nests. Research conducted during the 2015 breeding season will determine the validity of this trend, account for effect of frequency of climbing at a site regardless of climber presence, and will also consider avian species composition and other biotic diversity at cliff sites. Results will indicate whether or not rock climbing negatively impacts cliff specialist bird species and larger cliff communities within the park. Ultimately, these results will aid the City of Boulder management in providing for the needs of both birds and recreationalists.