Thursday, August 9, 2018: 11:10 AM
238, New Orleans Ernest N. Morial Convention Center
Marion Barbé, Institut de Recherche sur les Forêts, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC, Canada, Mathieu Bouchard, Direction de la recherche forestière, Ministère des Forêts, de la Faune et des Parcs, Québec, QC, Canada and Nicole Fenton, Forest research institute, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC, Canada
Background/Question/Methods
The capacity of communities to adapt drives the resilience and vulnerability of ecosystems to environmental changes. This subject has been a hot topic in boreal forests due to the greater effect of global warming at northern latitudes. However, to date it has been examined solely at the whole boreal scale and with the entire focus on trees, limiting our true understanding of the adaptation ability of different types of boreal communities to changes. We propose an initial reconsideration of this topic by splitting the boreal forest into coniferous and mixedwood forest types based on their overstory tree composition, and by using bryophytes as indicators of environmental changes. Bryophytes were sampled in coniferous and mixedwood forests across the province of Québec between the 47°N and the 50°N parallels, which represents a temperature gradient (mean annual temperature of +2.30°C south; -1.40°C north). Overall bryophyte community composition, as well as community compositions on three key microhabitats (live tree bases, deadwood, forest floor), were analyzed in both forest types across the temperature gradient. Climatic variables (abiotic) and stands characteristics (biotic) were also measured.
Results/Conclusions
A more marked change in bryophyte composition between the warmer and the colder locations was observed in mixedwood compared to coniferous forests. At a finer scale, in coniferous forests, communities inhabiting live tree bases and deadwood (corticolous), were primarily related to stand structure whereas they were mainly related to temperature in mixedwood forests. Bryophytes from mixedwood forests, especially corticolous species, were climate-sensitive and represent a potential target group to investigate the effects of climate change. In contrast, bryophyte communities from coniferous forests were stand structure-sensitive, with little response to climate. In conclusion, the dynamics of mixedwood forests was allogenic, with bryophyte communities adapted to temperature change. These forests acted like colanders as bryophytes are subject to variation in the regional climate, a potential indicator of forest resilience. In contrast, the dynamics of coniferous forests was autogenic and they acted as solid domes, where communities are only subject to local stand conditions. Is resilience of the whole boreal forest a question of perspective? The debate is open…
