Recreational trails reduce lichen and bryophyte diversity and the occurrence of rare species

Increasing recreational use of natural areas may pose a threat to biodiversity, particularly in sensitive high-elevation ecosystems. Lichens and bryophytes (collectively termed cryptogams here) contribute substantially to biodiversity in almost all terrestrial ecosystems, but their response to disturbance from recreation has rarely been studied.

We inventoried lichen and bryophyte communities and analyzed impacts of disturbance and environmental variables at four study areas in Mount Rainier National Park, Washington, USA. The study areas ranged from low-elevation, wet temperate forests to alpine environments and adjacent subalpine forests.

We sampled cryptogam communities using both 1 x 1 meter quadrats as well as larger, circular, fixed-area plots. For both the quadrats and the plots, data on species composition and environmental variables we measured are included in separate files. We also include a data file of functional traits for cryptogams we encountered.

Large, high-quality cryptogam community datasets are rare, and these data may be useful for further analyses.