Managing for the unexpected: Building resilient forest landscapes to cope with global change

Abstract

Natural disturbances exacerbated by novel climate regimes are increasing worldwide, threatening the ability of forest ecosystems to mitigate global warming through carbon sequestration and to provide other key ecosystem services. One way to cope with unknown disturbance events is to promote the ecological resilience of the forest by increasing both functional trait and structural diversity and by fostering functional connectivity of the landscape to ensure a rapid and efficient self‐reorganization of the system. We investigated how expected and unexpected variations in climate and biotic disturbances affect ecological resilience and carbon storage in a forested region in southeastern Canada. Using a process‐based forest landscape model (LANDIS‐II), we simulated ecosystem responses to climate change and insect outbreaks under different forest policy scenarios—including a novel approach based on functional diversification and network analysis—and tested how the potentially most damaging insect pests interact with changes in forest composition and structure due to changing climate and management. We found that climate warming, lengthening the vegetation season, will increase forest productivity and carbon storage, but unexpected impacts of drought and insect outbreaks will drastically reduce such variables. Generalist, non‐native insects feeding on hardwood are the most damaging biotic agents for our region, and their monitoring and early detection should be a priority for forest authorities. Higher forest diversity driven by climate‐smart management and fostered by climate change that promotes warm‐adapted species, might increase disturbance severity. However, alternative forest policy scenarios led to a higher functional and structural diversity as well as functional connectivity—and thus to higher ecological resilience—than conventional management. Our results demonstrate that adopting a landscape‐scale perspective by planning interventions strategically in space and adopting a functional trait approach to diversify forests is promising for enhancing ecological resilience under unexpected global change stressors.

Climate change may increase Quebec boreal forest productivity in high latitudes by shifting its current composition

“…In PnET-Succession, speciesspecific life-history traits reflect the competitive ability for resources (e.g., light and water), which have implications for simulated tree species range boundary shifts. PnET-Succession and LANDIS-II have been widely used in North America including Quebec boreal forest (Boulanger et al, 2017;Mina et al, 2021Mina et al, , 2022Molina et al, 2021). Complete details of the PnET-Succession extension are found in De Bruijn et al (2014) and Gustafson and Miranda (2019).…”

Vertical stratification of leaf physical traits exerts bottom-up pressures on insect herbivory in a sugar maple temperate forest

“…These insects play a crucial role as key trophic levels affecting forest ecosystem functions and production. While some of these insect herbivores may be pests, high insect diversity tends to decrease the severity of pest outbreaks and to improve forest resilience (Stemmelen et al 2022;Mina et al 2022).…”

A regional integrated assessment of the impacts of climate change and of the potential adaptation avenues for Quebec's forests

“…Other strategies seeking to balance timber supply and other forest values under climate change should be explored, such as the triad concept (Royer-Tardif et al 2021). Strategies aiming to improve functional redundancy in complex ecosystems also show promise (Messier et al 2019, Mina et al 2022. Transition strategies based on assisted migration of climate-adapted species or populations have also demonstrated the potential to provide benefits under climate change (e.g., Pedlar et al 2012).…”