Abstract Detail

Bryological and Lichenological Section/ABLS

Tessler, Michael [1], Clark, Theresa [2].

The Impact of Bouldering on Boulder-Associated Plants and Lichens.

Many popular bouldering sites lie within protected natural areas, yet no research has assessed whether the sport of bouldering (i.e. unroped climbing of short, vertical boulders usually less than 3.5 m tall) poses a threat to boulder-associated vegetation; such vegetation is known to be diverse and often includes rare species, many of which are saxicolous plants and lichens. This paucity of boulder related research is concerning for three reasons. First, bouldering usually involves the removal of any “troublesome” boulder-associated vegetation and soil in order to improve climbing conditions and ensure safety. Secondly, traditional roped climbing of vertical cliffs has been linked to reductions in the diversity of cliff-associated vegetation. And lastly, the sport of bouldering has been growing rapidly in recent decades and preemptive research and conservation efforts may protect these unique habitats before any present environmental footprint expands. Our study sought to quantify the impact of bouldering on boulder-associated vegetation in the Northern Shawangunk Ridge (Mohonk Preserve, New York). Our objectives were to (1) quantify differences between climbed and unclimbed boulders in terms of their abundance, richness, and composition of associated vegetation, (2) determine the relative contribution of physical boulder features and micro-environment to vegetation patterns, and (3) contrast boulder habitat targeted by boulderers with that of similar-sized, unclimbed, boulder faces. Climbed boulders supported lower species richness and percent cover when no environmental controls were considered. By functional group, these patterns were driven by lower abundance and richness of lichens, bryophytes, and herbaceous plants on climbed boulders, while that of woody plants did not differ significantly. Interestingly, temperature and relative humidity did not explain variation in the community as a whole, but significantly explained patterns in bryophyte and lichen abundance and percent cover independent of variation attributable to climbing impact. Boulder microtopography, microclimate, and local environment did not differ significantly from that of unclimbed boulders, with the exception of five boulder features: boulderers appear to favor boulder faces that are negatively-sloped and which possess fewer ledges, vertical cracks, and overhangs. Results at the scale of boulder microhabitats will elucidate where along boulders (i.e. the ground, lower face, middle face, upper face, or top) the impact of bouldering is most severe. Furthermore, results will detail the degree to which variation in boulder characteristics influence vegetation communities at two scales: entire boulders and boulder microhabitats. Lastly, recommendations for conservation of boulder-associated communities will be presented.  

1 - Richard Gilder Graduate School, American Museum of Natural History, New York, NY, USA
2 - University of Nevada, Las Vegas, Biological Sciences, 4505 S Maryland Parkway, Las Vegas, NV, 89119, USA

Keywords:
Vegetation structure
Rock habitat
disturbance
recreation
climbing impacts on cliffs
New York
microtopography
community assembly.

Presentation Type: Oral Paper:Papers for Sections
Session: 23
Location: River Fork/Grove
Date: Tuesday, July 29th, 2014
Time: 9:15 AM
Number: 23002
Abstract ID:895
Candidate for Awards:A. J. Sharp Award