Boreal Forest Multifunctionality Is Promoted by Low Soil Organic Matter Content and High Regional Bacterial Biodiversity in Northeastern Canada

Abstract

Boreal forests provide important ecosystem services, most notably being the mitigation of increasing atmospheric CO2 emissions. Microbial biodiversity, particularly the local diversity of fungi, has been shown to promote multiple functions of the boreal forests of Northeastern China. However, this microbial biodiversity-multifunctionality relationship has yet to be explored in Northeastern Canada, where historical environment have shaped a different regional pool of microbial diversity. This study focuses on the relationship between the soil microbiome and ecosystem multifunctionality, as well as the influence of pH and redox potential (Eh) on the regulation of such relationship. Structural equation modelling (SEM) was used to explore the different causal relationships existing in the studied ecosystems. In a managed part of the Canadian boreal forest, 156 forest polygons were sampled to (1) estimate the α- and β-diversity of fungal and bacterial communities and (2) measure 12 ecosystem functions mainly related to soil nutrient storage and cycling. Both bacteria and fungi influenced ecosystem multifunctionality, but on their own respective functions. Bacterial β-diversity was the most important factor increasing primary productivity and soil microbial biomass, while reducing soil emitted atmospheric CO2. Environmental characteristics, particularly low levels of organic matter in soil, were shown to have the strongest positive impact on boreal ecosystem multifunctionality. Overall, our results were consistent with those obtained in Northeastern China; however, some differences need to be further explored especially considering the history of forest management in Northeastern Canada.

Bacterial rather than fungal diversity and community assembly drive soil multifunctionality in a subtropical forest ecosystem

“…In recent decades, ecologists have explored the links between microbial diversity (or community diversity) and multiple simultaneous ecosystem processes and services (multifunctionality) (Hector and Bagchi, 2007; Bardgett and Van der Putten, 2014; Jing et al ., 2015; Delgado‐Baquerizo et al ., 2017; Manning et al ., 2018; Wagg et al ., 2019; Han et al ., 2021b). Growing evidence from many studies has demonstrated that the linkage between microbial diversity and ecosystem multifunctionality is more frequently positive and linear than saturating across a broad range of ecosystems – e.g., grassland (Byrnes et al ., 2014; Jing et al ., 2015; Wagg et al ., 2019), farmland (Luo et al ., 2019; Chen et al ., 2020), and boreal forest soils (Li et al ., 2019; Giguere‐Tremblay et al ., 2020), implying that microbial diversity could enhance soil multifunctionality. Meanwhile, observational experiments showed that losses in microbial functional diversity could result in the lowering (reduction) of several specific soil processes (e.g., emission of methane and nitrous oxide) (Trivedi et al ., 2019).…”

Effects of plant diversity, soil microbial diversity, and network complexity on ecosystem multifunctionality in a tropical rainforest

“…A previous study have found that soil microbial diversity drives the EMF in the terrestrial ecosystem ( Delgado-Baquerizo et al., 2016 ). Especially, soil bacterial diversity positively promoted EMF enhancement ( Giguere-Tremblay et al., 2020 ). However, soil fungal diversity was not significantly correlated with EMF ( Jing et al., 2015 ; Sun et al., 2023 ).…”