TITLE:
Lichen-Spruce Woodland Early Indicators of Ecological Resilience Following Silvicultural Disturbances in Québec’s Closed-Crown Forest Zone
AUTHORS:
Esteban Gonzalez, François Hébert, Jean-François Boucher, Pascal Sirois, Daniel Lord
KEYWORDS:
Afforestation; Black Spruce; Kalmia angustifolia; Rhododendron groenlandicum; Logging; Picea mariana; Vegetation Recovery; Scarification; Silviculture
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.3A,
March
29,
2013
ABSTRACT:
Lichen
woodlands (LW) located in the closed-crown boreal forest are not a successional
stage moving towards a closed black spruce feathermoss stand (FM), but an
alternative stable state, due to their previous forest history, and the occurrence of LWs
located nearby closed-crown FM stands. Therefore, afforestation in those LWs
through site preparation and plantation could shift back LW into FM stands. We
implemented an experimental design with different combinations of silvicultural treatments in both site types (LW,
FM). We monitored the evolution of plant diversity and the physiology of three
bio-indicators (Picea mariana, Kalmia angustifolia, Rhododendron groenlandicum) in different microsites created by the
silvicultural treatments. The return to the initial composition was noticed only
two years after treatments, especially in the LW stands, thus indicating a
higher level of early ecosystem resilience in LWs compared to FM stands.
Mean species cover, especially in the FM stands, decreased the most in the skid
trails created by logging, probably due to a lack of acclimation of bryophytes
to open stand conditions. Conversely, ericaceous shrubs and lichens found in
the LWs were already acclimated to open stand conditions, which give to LWs a
restructuring advantage compared to FM plant communities after
silvicultural treatments. Overall, FM and LW short-term resilience was similar,
indicating equally efficient ecosystem reorganization in both stands. The
comparable early resilience in managed LW and FM stands, in terms of plant
biodiversity, contradicts the presumed fragility of LW stands, especially in
this case where LWs are assumed to be an alternative stable state created by
compound disturbances. Silvicultural treatments maintained the functional group
diversity in LWs, a key element for ecosystem resilience. Therefore, this study
support the idea that plantation following site preparation in LWs could be a
valuable management strategy to reach several objectives, such as increasing
forest carbon sinks.