Species composition, microhabitat and dominant species traits aid persistence of Kalmia-black spruce shrub savannah in eastern Canada

Question: In eastern Canada, black spruce-Kalmia forests after wildfire turn to either spruce forest, Kalmia heath, or Kalmia-spruce shrub savannah (SS) depending on fire severity. Do species composition, microhabitat, soil, and dominant species traits in the island and heaths of SS can explain its persistence? Location: Eastern Canada. Methods: We compared species composition, microhabitat conditions, soil properties, and dominant species functional traits in island and heath of three SS sites in Terra Nova National Park, Newfoundland. We determined functional hypervolumes of the four most abundant species using four functional traits that represent resource acquisition and use. Results: High tree cover, cryptogamic species cover, and organic matter depth were associated with island; high light, soil moisture, and shrub cover were associated with heath. Heath soil had higher total N, and lower total C, P, C:N ratio, and K concentration than island soil. Heath had less functional trait variability. Ericaceous species showed a tradeoff between resource conservation in heath to resource acquisition in island. Conclusion: We conclude that the different microclimate, vegetation structure and function of island and heath combinedly contribute to the SS persistence.