Date de publication: / Author: Chagnon, Pierre-Luc - Lunaris - Découvrez les données de recherche canadiennes Résultats de recherche

Parasquive, Vlad; Brisson, Jacques; Guilbeault-Mayers, Xavier; Laliberté, Etienne; Chagnon, Pierre-Luc — 2023-05-15 Introduction: Plant nutrient acquisition strategies range along a spectrum from autonomous foraging to investment in cooperative foraging through mycorrhizal associations. However, in temperate ecosystems, many plant species encounter contrasted levels of symbiont availability in open fields versus closed forests. Little is known about how fungal partner availability may be associated with intraspecific variation in other root foraging traits in natural settings. Methods: Here, we addressed this issue by sampling saplings from two tree species: the arbuscular mycorrhizal (AM) Acer rubrum and the ectomycorrhizal (ECM) Quercus rubra from open fields (AM-dominated) and adjacent forest plots (ECM-dominated). For each species and environment, we measured morphological, architectural, and symbiotic root traits. Results: For the open field, Quercus had greater specific root length (SRL) while Acer had higher AM colonization and root diameter. In the closed forest, the opposite pattern was observed, namely Quercus had higher ECM colonization and Acer greater SRL. Discussion: Both species showed evidence of a shift toward autonomous root foraging in the habitat with low expected symbiont abundance (open field for Quercus and forest for Acer). Although the confounding effects of site abiotic properties could not be strictly controlled in this study, these results suggest that plants might adjust root foraging traits according to local habitat conditions. Synthesis: Our results shed new light on the intraspecific variation in plant position along the so-called “collaboration gradient”, and suggest that mycorrhizal symbiont availability, along with other factors such as competition and site properties, may contribute to this variation.

Replication Data for: Prairie restoration promotes the abundance and diversity of mutualistic arbuscular mycorrhizal fungi

Borealis

MacColl, Kevin; Tosi, Micaela; Chagnon, Pierre-Luc; MacDougall, Andrew; Dunfield, Kari; Maherali, Hafiz — 2024-03-20

Data from: Soil biotic quality lacks spatial structure and is positively associated with fertility in a northern grassland

Dryad

Chagnon, Pierre-Luc; Brown, Charlotte; Stotz, Gisela C.; Cahill, James F. — 2020-04-16 When placing roots in the soil, plants integrate information about soil nutrients, plant neighbours and beneficial/detrimental soil organisms. While the fine-scale spatial heterogeneity in soil nutrients and plant neighbours have been described previously, virtually nothing is known about the spatial structure in soil biotic quality (measured here as a soil Biota-Induced plant Growth Response, or BIGR), or its correlation with nutrients or neighbours. Such correlations could imply trade-offs in root placement decisions. Theory would predict that soil BIGR is (1) negatively related to soil fertility and (2) associated with plant community structure, such that plants influence soil biota (and vice versa) through plant-soil feedbacks. We would also expect that since plants have species-specific impacts on soil organisms, spatially homogeneous plant communities should also homogenize soil BIGR. Here, we test these hypotheses in a semiarid grassland by (1) characterizing the spatial structure of soil BIGR at a scale experienced by an individual plant and (2) correlating it to soil abiotic properties and plant community structure. We do so in two types of plant communities: (1) low-diversity patches dominated by an invasive grass (Bromus inermis Leyss.) and (2) patches covered mostly by native vegetation, with the expectation that dominance by Bromus would homogenize soil BIGR. Soil BIGR was spatially heterogeneous, but not autocorrelated. This was true in both vegetation types (Bromus-invaded vs. native patches). Conversely, soil abiotic properties and plant community structure were frequently spatially autocorrelated at similar scales. Also, contrary to many studies, we found a positive correlation between soil BIGR and soil fertility. Soil BIGR was also associated with plant community structure. Synthesis. The positive correlation between soil BIGR and some soil nutrient levels suggests that plants don't necessarily trade-off between foraging for nutrients vs. biotic interactions: nutritional cues could rather indicate the presence of beneficial soil biota. Moreover, the spatial structure in plant communities, coupled with their correlation with soil BIGR, jointly suggest that plant-soil feedbacks operate at local scales in the field: this has been identified in modelling studies as an important driver of plant coexistence.

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