Climate change isn’t just causing biodiversity loss for the trees in Canada’s forests — it’s also altering the diversity of plants growing under the canopy of those trees in ways that could weaken the ecosystem’s overall function, a University of Alberta-led study shows.
Using Canada’s National Forest Inventory database to evaluate decade-long shifts in local plant diversity in those “understory” communities, the research showed environmentally driven changes are reshaping the dominance of some species.
Though the number of shrub and moss types increased by eight and 11 per cent respectively per decade, the mix of herbs and mosses became less balanced, dropping by 14 and eight per cent — suggesting a few species are becoming disproportionately abundant.
The increase in species richness and the decline in evenness were linked to warmer temperatures, more nitrogen pollution, changes in water availability and more extreme seasonal temperature swings.
“The shifts in ground-level plant communities may gradually alter habitats and monopolize resources, ultimately reducing species richness and affecting beneficial functions such as soil carbon storage,” says postdoctoral researcher Xinli Chen, who co-led the study with soil scientist Scott Chang.
That insight could improve policy for monitoring and managing Canada’s natural forests, he adds.
“We need to consider how climate change affects those understory plants, and how that, in turn, can have an impact on the environment.”