| dc.description.abstract | Scope: In eastern Canada, black spruce (Picea mariana)-Kalmia angustifolia forest revert
into forest, or become Kalmia heath, or Kalmia-spruce shrub savannah (SS) depending on
fire severity. My main research objective was to identify the mechanisms that maintain
SS vegetation structure and function. I hypothesized that microhabitat conditions and
function of dominant plants of island and heath confer SS stability.
Methodology: I used a multivariate approach to quantify the difference in habitat
condition, floristic structure and composition between island and heath of SS. I compared
soil nutrient availability and litter decomposition between island and heath to assess
growth limitations and nutrient cycling. This was followed by determining functional
hypervolumes of the four most abundant species in island and heath considering four
functional traits representing resource acquisition and use. I used a dendrochronological
approach to determine island expansion rate to predict future island cover.
Results: Shrub cover, light availability, and soil moisture were positively related to heath,
and cryptogamic species and tree cover and organic matter depth were positively related
to island. Heath soil had higher total N, but lower total C, and K than island. All other
measured nutrients were similar. Black spruce litter decomposed faster than Kalmia. [...] | en_US |
