Disentangling how biodiversity facets link to ecosystem functioning is challenging, given the diverse mechanisms involved, including selection effect and niche complementarity along with competition and facilitation. The impact of flooding stress on these mechanisms has further been little explored. We evaluated the contribution of plant richness and identity, functional diversity and competition to community biomass under flooding relative to field capacity. One forb (Asclepias incarnata), one legume (Melilotus officinalis) and two grasses (Alopecurus pratensis and Phalaris arundinacea) were grown under these two water regimes alone or in mixtures. Community-weighted means (CWMs) and variances (CWVs) based on eight plant traits were related to biomass, and net biodiversity, complementarity and selection effects. Aboveground biomass, net biodiversity and selection effects increased with species and functional group richness only at field capacity. Melilotus officinalis increased biomass at field capacity, and P. arundinacea under flooding. Higher contribution of CWVs to biomass was observed at field capacity, and of CWMs under flooding. Flooding strongly influenced plant diversity-ecosystem productivity relationships by limiting species richness effect, modifying the identity of key species and changing the magnitude of complementarity and selection effects. Overall, promoting not only species but also functional diversity could help maintain ecosystem resilience in flood-prone environments.
Oil sands process-affected water (OSPW) contains naphthenic acid (NA) fraction compounds (NAFCs), structurally diverse organic acids regarded as a primary contributor to OSPW toxicity. Their persistence and complexity complicate characterization and risk assessment, while a no-discharge policy on OSPW makes reclamation an environmental priority. Phytoremediation represents a promising strategy for OSPW treatment, but its optimization requires a clearer mechanistic understanding of how NAFCs affect plant growth and development. An unresolved question is whether NAFCs act solely as toxicants or if they alter hormone signaling pathways in plants, particularly auxin signaling. Here, we demonstrate that exposure to model NAs and OSPW-derived NAFCs altered Arabidopsis thaliana (L.) Heynh. seedling root development in a manner phenotypically similar to that observed in other plant species. NAFC-treated seedlings exhibited reduced primary and lateral root elongation, stimulated adventitious rooting, and disrupted gravitropic responses. Fluorescent transcriptional reporter assays confirmed that NAFC exposure enhanced auxin-responsive expression, while pharmacological experiments suggested that NAFC uptake and distribution involve auxin transporters. Auxin-induced changes in root development may limit water and nutrient acquisition and diminish plant fitness. However, variation in auxin metabolism, transport, and receptor sensitivity among plant species could offer opportunities to identify or develop genotypes better suited for remediation of OSPW-affected sites.
Plant responses to global change are well-studied in spring and early summer but less so in late summer, particularly in tundra ecosystems. It remains unclear whether senescence is driven more by temperature or photoperiod, and whether species respond similarly under late-season warming. We used growth chambers to test how photoperiod and late-season warming affect leaf senescence over two growing seasons in three tundra species collected from the same latitude in southwestern Yukon, Canada— Artemisia norvegica ssp. saxatilis (Bess. ex Hook.), Poa alpina (L.), and Trisetum spicatum (L.), representing one forb and two grasses, respectively. Senescence was quantified by digitally measuring leaf colour change in the final weeks of the experimental season. Both grasses were sensitive to temperature and daylength, but A. norvegica was only marginally affected by daylength. Interestingly, while cooling temperatures increase senescence over stable temperatures, autumn-like shortening daylengths decrease senescence over constant daylengths. In Poa alpina, reproductive individuals showed faster leaf senescence, and panicle senescence was temperature sensitive. The phenology of foliar and reproductive tissues may respond independently, showing that well-documented early-season responses to northern warming do not always predict late-season phenology.
Ethnobotany is a multidisciplinary field, highly relevant in the context of environmental, social and cultural changes. Since the first European explorations of the Inuit Nunangat, numerous ethnobotanical studies, using various methods, have documented the use of more than 300 plant taxa by Inuit communities. This paper addresses the strengths and limitations of 'semi-structured group interviews' through the lens of a case study in Kitikmeot (Nunavut, Canada), broadening our perspectives and understanding of ethnobotanical research done with Inuit communities. A literature review was conducted to highlight the most and least commonly used methods in ethnobotany in Inuit Nunangat. Semi-structured group interviews can increase sample size but require structured coordination of logistics between researchers and community members. They provide an opportunity for researchers to propose future research projects with communities and communicating the results of previous and ongoing projects. This emphasizes the importance of developing transparent and appropriate participatory traditional knowledge research projects that lead to socially and scientifically meaningful results as they are of the essence when addressing Indigenous ethics and methodology in ethnobotany. A fluid and respectful dialogue between Inuit community members and researchers, in a designed and preserved ethical space is an ideal setting to attain better results.
The leaf economics spectrum (LES) is a widely described pattern in plant ecology, representing plant resource-use strategies described by variability in resource conservative to resource acquisitive leaf functional traits. Root traits are also hypothesized to vary along a root economics spectrum (RES) defining belowground resource acquisition strategies. While observed in wild plants, it is unclear if the RES defines belowground strategies in crops, and if a potential RES covaries with a LES in crops. Using 12 cultivars of grapevine scions, spread across three unique rootstocks, we measured five RES traits—specific root length (SRL), root tissue density (RTD), root diameter (D), root nitrogen and carbon concentrations—and three LES traits—leaf mass per area, leaf N concentrations, light-saturated photosynthetic capacity on a per leaf mass basis. We tested for (1) the existence of an intraspecific RES in grapevine, and (2) covariation between an LES and RES. Root traits varied along a conservative-acquisitive RES, defined by positive covariation between RTD and D, which both traded off against SRL. Scion identity explained ~49.2% of belowground trait variation. We also found evidence for orthogonality between the RES and LES, suggesting that above- and belowground strategies vary independently of one another in grapevine.
