by Claire Morin | 30 January 2019
Published in Ecological Applications 28(5): 1282-1291. https://doi.org/10.1002/eap.1727
The development of efficient ecosystem resilience indicators was identified as one of the key research priorities in the improvement of existing sustainable forest management frameworks. Two indicators of tree diversity associated with ecosystem functioning have recently received particular attention in the literature: functional redundancy (FR) and response diversity (RD). We examined how these indicators could be used to predict post-logging productivity in forests of Québec, Canada. We analysed the relationships between pre-logging FR and RD, as measured with sample plots, and post-logging productivity, measured as seasonal variation in enhanced vegetation index obtained from MODIS satellite imagery. The effects of the deciduous and coniferous tree components in our pre-disturbance diversity assessments were isolated in order to examine the hypothesis that they have different impacts on post-disturbance productivity. We also examined the role of tree species richness and species identity effects. Our analysis revealed the complementary nature of traditional biodiversity indicators and trait-based approaches in the study of biodiversity-ecosystem-functioning relationships in dynamic ecosystems. We report a significant and positive relationship between pre-disturbance deciduous RD and post-disturbance productivity, as well as an unexpected significant negative effect of coniferous RD on productivity. This negative relationship with post-logging productivity likely results from slower coniferous regeneration speeds and from the relatively short temporal scale examined. Negative black-spruce-mediated identity effects were likely associated with increased stand vulnerability to paludification and invasion by ericaceous shrubs that slow down forest regeneration. Response diversity outperformed functional redundancy as a measure of post-disturbance productivity most likely due to the stand-replacing nature of the disturbance considered. To the best of our knowledge, this is among the first studies to report a negative significant relationship between a component of RD and ecosystem functioning, namely coniferous RD and forest ecosystem productivity after a stand-replacing disturbance.
by Claire Morin | 30 January 2019
Published in Ecological indicators 72: 288-296. https//doi.org/10.1016/j.ecolind.2016.08.033
Forest age structure is one of the main indicators of biodiversity in temperate and boreal forests worldwide. This indicator was mainly chosen for the conservation of a subset of rare or sensitive species related to the oldest age classes, not to capture variability across the entire biodiversity spectrum, but is often considered as such. In this study, we analysed alpha and beta diversity in temporary plots of western Quebec, Canada, to consider biodiversity indicators complementary to existing forest age structure targets. Our analysis revealed that considered individually, stand characteristics such as cover type and height are better predictors of changes in site-level contribution to tree beta diversity than age. We also show that plots belonging to different age classes can be similar in terms of tree alpha diversity. Height class was found to have a more significant impact on tree alpha diversity than expected: height was more important than age in coniferous forests, and in deciduous and mixedwood stands it frequently complemented age in explaining the observed diversity patterns. Our results suggest that forest age structure target levels should not be used as the sole indicator of ecosystem sustainability, and that some mature secondary stands can provide significant contributions to biodiversity. We propose that more efficient trade-offs between forest exploitation, ecosystem functioning and environmental conservation can be attained if: (i) forest age structure targets are complemented by cover type and stand height; or (ii) complementary biodiversity indicators of ecosystem sustainability are implemented.
by Claire Morin | 30 January 2019
Published in Forest Ecology and Management 368: 63-70. https://doi.org/10.1016/j.foreco.2016.02.029
Forest fragmentation by management activities has been implicated in the decline of forest biodiversity. Even though boreal ecosystems are generally deemed quite resilient to disturbance effects, high contemporary levels of disturbance might push forest-interior species toward decline or extinction. In this study, we examined beetle communities in forest patches of different sizes, including clearcuts, residual postharvest patches from 0.03 to 50 ha in size, and large mature forest tracts (>1000 ha). Overall, community structure follows a gradient between clearcuts and large mature forest tracts, even if patch size effects were more difficult to detect among patches >2.5 ha. Beetles were most abundant in clearcuts, and species richness was highest in small tree groups (0.03–0.05 ha). The effects of fragmentation were strongly conditioned by beetle feeding habits. Predators and xylophagous beetles were mostly associated with clearcuts or smaller patches (i.e., small tree groups or large tree groups [0.3–0.5 ha]), whereas fungivorous beetles were associated with forest-interior habitats. Although many forest-interior species were still present in relatively small patches 1–5 years after harvesting, negative effects of habitat fragmentation on these species might increase in the long-term.
by Claire Morin | 30 January 2019
Published in Canadian Journal of Forest Research 45(5): 515-528. https://doi.org/10.1139/cjfr-2014-0260
The boreal forest ecosystem is one of the largest frontier forests of the world, providing many ecological services to society. Boreal forests are also economically important, but forest harvesting and management become increasingly difficult when one moves from south to north in boreal environments. An approach was thus developed to assess the suitability of land units for timber production in a sustainable forest management (SFM) context in the northern boreal forest of Quebec (Canada). This area includes all of Quebec’s spruce – feather moss bioclimatic domain (closed forest), as well as the southern portion of the spruce–lichen bioclimatic domain (open woodland). Four criteria specific to the biophysical aspects of SFM were evaluated in 1114 land districts: physical environment, timber production capacity, forest vulnerability to fire (e.g., probability that it reaches maturity), and conservation of biodiversity. Indicators and acceptability cutoff values were determined for each selected criterion, and a sequential analysis was developed to evaluate if a land district has the potential to be sustainably managed. This analytical process led to the classification of land districts into three categories: slightly sensitive (SFM possible); moderately sensitive (SFM possible under certain conditions); and highly sensitive (SFM not possible). The results show that 354 land districts were highly sensitive, 62 due to physical constraints (7.5% of the area), 130 due to insufficient potential productivity (15.4% of the area), 92 due to insufficient potential productivity to account for the fire risk (13.8% of the area), and 70 due to an insufficient proportion of tall and dense forest habitats (7.7% of the area — biodiversity criterion). This work provides scientific background to proposing a northern limit for forest management activities in Quebec. The developed approach could be useful in other jurisdictions to address similar issues.
by Marie-Claude Boileau | 30 January 2019
The protection measure outlined in this document for the Bicknell’s Thrush pertain only to forest management activities. It was prepared by a working group (wildlife subcommittee) under the Administrative agreement on the protection of threatened and vulnerable plant and animal species and other biodiversity components in Quebec’s forests (Ministère du Développement durable, de l’Environnement et des Parcs and Ministère des Ressources naturelles et de la faune, 2010). The document is intended mainly for forest planners and managers responsible for preparing integrated forest management plans; it therefore includes several notes intended specifically for them.
