Abstract
BackgroundIn the context of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec (Canada). Using contemporary and long-term fire cycles, each natural forest landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape variability.MethodsThe study encompassed a forested area of 175 000 km2 divided into 14 landscapes. Using a framework that integrates fire cycles, age structure and forest dynamics, we characterized the forest composition and age structures that resulted from three historical fire cycles (110, 140, and 180 years) representative of the boreal forest of eastern Canada. The modeled natural landscapes were compared with present-day landscapes in regard to the proportion of old-growth forests (landscape level) and the proportion of late-successional forest stands (landscape level and potential vegetation type).ResultsFour landscapes (39%) remain within their natural range of variability. In contrast, nine landscapes (54%) show a large gap between natural and present-day landscapes. These nine are located in the southern portion of the study area, and are mainly associated with Abies-Betula vegetation where human activities have contributed to a strong increase in the proportion of Populus tremuloides stands (early-successional stages) and a decrease of old-growth forest stands (more than 100 years old). A single landscape (7%), substantially changed from its potential natural state, is a candidate for adaptive-based management.ConclusionComparison of corresponding natural (reference conditions) and present-day landscapes showed that ten landscapes reflecting an important shift in forest composition and age structure could be considered beyond the range of their natural variability. The description of a landscape’s natural variability at the scale of several millennia can be considered a moving benchmark that can be re-evaluated in the context of climate change. Focusing on regional landscape characteristics and long-term natural variability of vegetation and forest age structure represents a step forward in methodology for defining reference conditions and following shifts in landscape over time.
Highlights
In the context of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec (Canada)
The natural variability associated with this fire cycle extends from 56 to 315 years (Additional file 1: Appendix 3)
In accordance with contemporary ecologists (Bergeron et al 2001, 2004; Lesieur et al 2002) and paleoecological studies (Carcaillet et al 2010), we estimate that the natural variability of this fire cycle extends from 47 to 340 years
Summary
In the context of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec (Canada). Natural ecosystems and landscapes can offer an objective benchmark for guiding short-term and long-term goals for management and restoration of ecosystems (Swetnam et al, 1999; Gauthier et al 2008; Keane et al 2009; Kuuluvainen 2009, 2017) Such an approach to ecosystem management increasingly considers the effect of human activities on landscape (logging, anthropogenic fires), in addition to the influence of global climate change. The estimated temperature increases in our study area (2 °C according to RCP 4.5 and 6.0, Boulanger et al 2014) could favor the development of ecosystems similar to those observed during the warm early Holocene period, dominated by early successional species (8500 to 6500 BP) (Ali et al 2012) These new ecosystems could be considered alternative stable states (Scheffer & Carpenter 2003; Jasinski & Payette 2005), because they follow from a previous ecosystem with clearly defined characteristics. It is absorbed, through the capacity of species to adapt to an ecosystem’s modifications following human disturbances and climate change (Kuuluvainen & Siitonen 2013; Gauthier et al 2015; Kuuluvainen 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
