WHITE SPRUCE (PICEA GLAUCA), MOOSE (ALCES ALCES) AND THE ORIGIN OF A ZOOTIC DISCLIMAX COMMUNITY ON ISLE ROYALE

<p>Understory herbivory combined with canopy loss alters trajectories of forest succession, and in extreme cases may produce novel landscapes dominated by the groundcover layer. I investigated the response of woody species to savannas which have emerged in Isle Royale National Park as a result of moose herbivory. I used dendrochronological methods and microsite plots to describe the spatial, temporal, and competitive responses of white spruce (<em>Picea glauca</em>), a non-palatable species, to the savanna environment. Most tree species had lower densities in savannas, however bird-dispersed species mountain ash (<em>Sorbus decora</em>)<em> </em>and chokecherry (<em>Prunus virginiana</em>) were increasing in older savannas. White spruce has increased more or less synchronously in both savanna and forest sites, with new establishment favored by sites transitioning from forest to savanna. Spruce seedling density increased with forb cover and plant species richness and decreased with plant litter depth, an effect which intensified with savanna age. Spatial patterns in savannas reflected clustering attributable to seed dispersal and microsite limitation, suggesting long-sustaining patterns of microsite heterogeneity in open savannas.</p>

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2015

Author dc:creator

• Caird, Stephen C

Contributors dc:contributor

• Alan Rebertus

• Herbivory
• Alces alces
• Picea glauca
• savannas
• dendrochronology
• seedbed microsite
• Other Forestry and Forest Sciences

Repository record dc:identifier

https://commons.nmu.edu/theses/48

OAI identifier oai:identifier

oai:commons.nmu.edu:theses-1052