Co-ordinating editor: C. D. Canham.
Aspen succession and nitrogen loading: a case for epiphytic lichens as bioindicators in the Rocky Mountains, USA
Version of Record online: 20 MAY 2009
© 2009 International Association for Vegetation Science
Journal of Vegetation Science
Volume 20, Issue 3, pages 498–510, June 2009
How to Cite
Rogers, P. C., Moore, K. D. and Ryel, R. J. (2009), Aspen succession and nitrogen loading: a case for epiphytic lichens as bioindicators in the Rocky Mountains, USA. Journal of Vegetation Science, 20: 498–510. doi: 10.1111/j.1654-1103.2009.01064.x
- Issue online: 20 MAY 2009
- Version of Record online: 20 MAY 2009
- Received 13 February 2009; Accepted 17 February 2009.
- Community analysis;
- Phaeophyscia nigricans;
- Populus tremuloides
Question: Can lichen communities be used to assess short- and long-term factors affecting seral quaking aspen (Populus tremuloides) communities at the landscape scale?
Location: Bear River Range, within the Rocky Mountains, in northern Utah and southern Idaho, USA.
Method: Forty-seven randomly selected mid-elevation aspen stands were sampled for lichens and stand conditions. Plots were characterized according to tree species cover, basal area, stand age, bole scarring, tree damage, and presence of lichen species. We also recorded ammonia emissions with passive sensors at 25 urban and agricultural sites throughout an adjacent populated valley upwind of the forest stands. Nonmetric multidimensional scaling (NMS) ordination was used to evaluate an array of 20 variables suspected to influence lichen communities.
Results: In NMS, forest succession explained most variance in lichen composition and abundance, although atmospheric nitrogen from local agricultural and urban sources also significantly influenced the lichen communities. Abundance of nitrophilous lichen species decreased with distance from peak ammonia sources and the urban center in all aspen succession classes. One lichen, Phaeophyscia nigricans, was found to be an effective bioindicator of nitrogen loading.
Conclusions: Lichen communities in this landscape assessment of aspen forests showed clear responses to long-term (stand succession) and short-term (nitrogen deposition) influences. At the same time, several environmental factors (e.g. tree damage and scarring, distance to valley, topography, and stand age) had little influence on these same lichen communities. We recommend further use of epiphytic lichens as bioindicators of dynamic forest conditions.