Abstract Detail

Bryological and Lichenological Section/ABLS

Tessler, Michael [1], Clark, Theresa An [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 < 3.5 m tall) poses a threat to boulder-associated vegetation. Such vegetation is often diverse and includes rare saxicolous plants and lichens. This paucity of boulder related research is concerning for three reasons. First, bouldering usually involves the removal of any boulder-associated vegetation and soil that could improve climbing conditions. Secondly, traditional roped climbing of vertical cliffs has been linked to reductions in the diversity of cliff-associated vegetation. And thirdly, the sport has been growing rapidly in recent decades, and assessing environmental impact must be done before it is too late for conservation. Therefore, our study sought to quantify the impact of bouldering on vegetation in the northern Shawangunks (Mohonk Preserve, New York). Our objectives were to (1) quantify differences between climbed and unclimbed boulders in terms of their abundance, richness, and vegetational composition, (2) determine the relationship between physical boulder features, micro-environment, and vegetation patterns, and (3) contrast climbed and unclimbed boulder habitat using spatially paired boulders of similar size.
We found the frequency of 118 rock-associated plant or lichen species did not vary significantly between 25 climbed-unclimbed boulder pairs, but climbed boulders did support lower species richness and percent cover. Specifically, lichens and bryophytes were less diverse, while the richness of vascular plants did not appear impacted. The mean abundance of bryophytes was statistically lower on climbed boulders, while lichens and vascular plants showed this pattern as a nonsignificant trend. Interestingly, temperature and relative humidity did not explain variation in the community as a whole, but could explain patterns in bryophyte and lichen percent cover. NMDS ordination suggests that community composition among the 50 sampled boulders is most strongly related to location of the five bouldering sites, while climbing impact on composition was negligible. Mean boulder temperature, humidity, and macro-environmental features did not differ significantly from that of unclimbed boulders, but four micro-environmental features varied: climbed boulders had lower soil volume and were covered by less litter, soil, and coarse woody debris. Results will present mixed effects models that reveal the estimated impact of bouldering after accounting for variation in the vegetation that can be explained by environmental features potentially confounded with climbing impact. Lastly, recommendations for conservation of boulder-associated communities will be presented.

1 - American Museum of Natural History, Richard Glider Graduate School, New York, NY, USA
2 - University Of Nevada, Las Vegas, Biology, 4505 S Maryland Parkway, Las Vegas, NV, 89154, USA

Keywords:
conservation
Community ecology
bryophytes
lichens
recreation.

Presentation Type: Oral Paper:Papers for Sections
Session: 38
Location: Salon 8/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:45 AM
Number: 38002
Abstract ID:1344
Candidate for Awards:A. J. Sharp Award