Data from: Rock climbing activity and physical habitat attributes impact avian community diversity in cliff environments

As the sport of outdoor rock climbing rapidly grows, there is increasing
pressure to understand how it can affect communities of organisms in cliff
habitats. To that end, we surveyed 32 cliff sites in Boulder, Colorado,
USA, and assessed the relative roles of human recreation and natural
habitat features as drivers of bird diversity and activity. We detected
only native avian species during our observations. Whereas avian abundance
was not affected by climbing, avian species diversity and community
conservation value were higher at low-use climbing formations. Models
indicated that climber presence and cliff aspect were important predictors
of both avian diversity and avian cliff use within our study area, while
long-term climbing use frequency has a smaller, but still negative
association with conservation value and cliff use by birds in the area. In
contrast, the diversity of species on the cliff itself was not affected by
any of our measured factors. To assess additional community dynamics, we
surveyed vegetation and arthropods at ten site pairs. Climbing negatively
affected lichen communities, but did not significantly affect other
vegetation metrics or arthropods. We found no correlations between avian
diversity and diversity of either vegetation or arthropods. Avian cliff
use rate was positively correlated with arthropod biomass. We conclude
that while rock climbing is associated with lower community diversity at
cliffs, some common cliff-dwelling birds, arthropods and plants appear to
be tolerant of climbing activity. An abiotic factor, cliff aspect strongly
affected patterns of both avian diversity and cliff use, suggesting that
the negative effects of rock climbing may be mitigated by informed
management of cliff habitat that considers multiple site features.