| Abstract Detail
The biology of rarity: Conservation of bryophytes and lichens Schmull, Michaela [1]. Site factors determining epiphytic lichen distribution in a dieback-affected spruce-fir forest on Whiteface Mountain, New York. Epiphytic lichen distribution on trunks of living and dead Picea rubens and Abies balsamea and its dependency on chemical and microclimatic site factors were studied in a spruce-fir forest on Whiteface Mountain, New York, USA.
Epiphytic lichen diversity was considerably higher on dead compared to living trees and on fir compared to spruce. Diversity differed more between living and dead spruce than between living and dead fir.
Cover of most lichen species decreased with increasing mean concentration of NO3- in stem flow. Concentrations of NO3-were higher on living spruce compared to dead spruce and to living and dead fir. Additionally, NO3- was found experimentally to decrease chlorophyll content of Hypogymnia physodes compared to the controls, whereas ergosterol concentrations remained unaffected. This result indicates that a dependence of lichen cover on NO3- concentrations in stemflow may be the cause for negative correlations. Mn in the stemflow, known to damage soredia of Hypogymnia physodes, negatively correlated with cover of Mycoblastus sanguinarius and Parmelia saxatilis. However, the present work shows that concentrations measured in stem flow were considerably lower than in experimental studies.
Mn concentration of A. balsamea bark was considerably higher than in stemflow. Mn is known to limit epiphytic lichen abundance on Picea abies in the Harz Mountains, Germany, where total Mn concentrations in the bark are much lower than on Whiteface Mountain. Total Mn concentrations in bark of P. rubens on Whiteface Mountain were in the same range as in bark of P. abies in Germany. X-ray microanalysis showed that A. balsamea immobilized most Mn in crystals in spongy cork and in sclerotic phelloid cells of the outer bark and explains the high lichen abundance on A. balsamea despite the high total Mn concentrations.
Microclimatic parameters did not differ between fir and spruce, nor between living and dead trees.
1 - University of Goettingen, Department of Systematic Botany, Albrecht von Haller Institute for Plant Sciences, Untere Karspuele 2, Goettingen, D-37073, Germany
Keywords:
epiphytic lichens
precipitation chemistry
forest dieback
nitrate toxicity
microclimate
nitrate
manganese.
Presentation Type: Symposium
Session: 7-5
Location: Ballroom 3 (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 10:45 AM
Abstract ID:96 |
