More Like this

1. Nutrient exchange within common mycorrhizal networks is altered in a multispecies environment

   https://doi.org/10.1111/1365-2435.14723  

   Řezáčová, Veronika; Weremijewicz, Joanna; Michalová, Tereza (December 2024, Functional Ecology)

   Abstract Although it is known that arbuscular common mycorrhizal networks (CMNs) mediate below‐ground interactions between one or two species, little is understood about their role in mediating interactions among multiple, co‐occurring plant species.We investigated the CMN‐mediated interactions among two Central European species,Inula conyzaeandCrepis bienniswithin pots and the impact of a third plant, an invasiveEchinops sphaerocephalus, on these relationships. We examined changes in C‐to‐P exchange within a CMN formed byFunneliformis mosseaesourced from Central Europe by tracking plant C cost with¹³C signatures of 16:1ω5 and P acquisition to hosts with³³P only accessible to CMNs.When only native plants were present, the C cost was consistent for both species, despite CMNs favouringC. bienniswith P uptake. In the presence ofE. sphaerocephalus, CMNs also favouredC. bienniswith P, but whileC. biennisandE. sphaerocephalusprovisioned similarly large portions of¹³C,I. conyzaeprovided less. Mycorrhizal P acquisition, therefore, was the costliest forE. sphaerocephalus, which likely mitigated someI. conyzae's C cost even though both received a low proportion of³³P from CMNs.Echinops sphaerocephalusaltered mineral nutrient and C exchange proportions between native plants and their CMN, suggesting that this species alters below‐ground plant interactions and that not only specific characteristic of plant host and fungal partner but also the wider plant community mediates resource exchanges between CMNs and individual plants. Read the freePlain Language Summaryfor this article on the Journal blog. 

   more » « less
2. Herbarium specimens reveal that mycorrhizal type does not mediate declining temperate tree nitrogen status over a century of environmental change

   https://doi.org/10.1111/nph.19452  

   Michaud, Talia J; Cline, Lauren C; Hobbie, Erik A; Gutknecht, Jessica_L M; Kennedy, Peter G (May 2024, New Phytologist)

   Summary Rising atmospheric carbon dioxide concentrations (CO₂) and atmospheric nitrogen (N) deposition have contrasting effects on ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) symbioses, potentially mediating forest responses to environmental change.In this study, we evaluated the cumulative effects of historical environmental change on N concentrations and δ¹⁵N values in AM plants, EM plants, EM fungi, and saprotrophic fungi using herbarium specimens collected in Minnesota, USA from 1871 to 2016. To better understand mycorrhizal mediation of foliar δ¹⁵N, we also analyzed a subset of previously published foliar δ¹⁵N values from across the United States to parse the effects of N deposition and CO₂rise.Over the last century in Minnesota, N concentrations declined among all groups except saprotrophic fungi. δ¹⁵N also declined among all groups of plants and fungi; however, foliar δ¹⁵N declined less in EM plants than in AM plants. In the analysis of previously published foliar δ¹⁵N values, this slope difference between EM and AM plants was better explained by nitrogen deposition than by CO₂rise.Mycorrhizal type did not explain trajectories of plant N concentrations. Instead, plants and EM fungi exhibited similar declines in N concentrations, consistent with declining forest N status despite moderate levels of N deposition. 

   more » « less
3. Soil resource acquisition strategy modulates global plant nutrient and water economics

   https://doi.org/10.1111/nph.70087  

   Cheaib, Alissar; Chieppa, Jeff; Perkowski, Evan A; Smith, Nicholas G (May 2025, New Phytologist)

   Summary Natural selection favors growth by selecting a combination of plant traits that maximize photosynthetic CO₂assimilation at the lowest combined carbon costs of resource acquisition and use. We quantified how soil nutrient availability, plant nutrient acquisition strategies, and aridity modulate the variability in plant costs of nutrient acquisition relative to water acquisition (β).We used an eco‐evolutionary optimality framework and a global carbon isotope dataset to quantify β.Under low soil nitrogen‐to‐carbon (N : C) ratios, a mining strategy (symbioses with ectomycorrhizal and ericoid mycorrhizal fungi) reduced β by mining organic nitrogen, compared with a scavenging strategy (symbioses with arbuscular mycorrhizal fungi). Conversely, under high N : C ratios, scavenging strategies reduced β by effectively scavenging soluble nitrogen, compared with mining strategies. N₂‐fixing plants did not exhibit reduced β under low N : C ratios compared with non‐N₂‐fixing plants. Moisture increased β only in plants using a scavenging strategy, reflecting direct impacts of aridity on the carbon costs of maintaining transpiration in these plants. Nitrogen and phosphorus colimitation further modulated β.Our findings provide a framework for simulating the variability of plant economics due to plant nutrient acquisition strategies in earth system models. 

   more » « less
4. Soil microenvironmental variation drives below‐ground trait variation and interacts with macroclimate to structure above‐ground trait variation of arctic shrubs

   https://doi.org/10.1111/1365-2745.14278  

   Fraterrigo, Jennifer M; Chen, Weile; Loyal, Joshua; Euskirchen, Eugénie S (April 2024, Journal of Ecology)

   Henn, J (Ed.)

   Abstract Intraspecific trait variation can influence plant performance in different environments and may thereby determine the ability of individual plants to respond to climate change. However, our understanding of its patterns and environmental drivers across different spatial scales is incomplete, especially in understudied regions like the Arctic.To fill this knowledge gap, we examined above‐ground and below‐ground traits from three shrub taxa expanding across the tundra biome and evaluated their relationships with multiple microenvironmental and macroclimatic factors. The traits reflected plant size and structure (plant height, leaf area and root to shoot ratio), leaf economics (specific leaf area, nitrogen content), and root economics and collaboration with mycorrhizal fungi (specific root length, root tissue density, nitrogen content, and ectomycorrhizal colonisation intensity). We also measured leaf and root δ¹⁵N and leaf δ¹³C to characterise nitrogen source and acquisition pathways and plant water stress. Traits were measured in replicated plots (N = 135) varying in soil microclimate, thaw depth and organic layer thickness established across five sites spanning a macroclimate gradient in northern Alaska. This hierarchical design allowed us to disentangle the independent and combined effects of fine‐scale and broad‐scale factors on intraspecific trait variation.We found substantial intraspecific variation at fine spatial scales for most traits and less variation along the macroclimate gradient and between shrub taxa. Consistent with these patterns, microenvironmental factors, mainly soil moisture and thaw depth, interacted with macroclimate, mainly climatic water deficit, to structure size‐structural and leaf trait variation. In contrast, most root traits responded additively to thaw depth and macroclimate.Synthesis. Our results demonstrate that above‐ground and below‐ground tundra shrub traits respond differently to microenvironmental and macroclimatic variation. These differing responses contribute to substantial trait variation at fine spatial scales and may decouple above‐ground and below‐ground trait responses to climate change. 

   more » « less
5. Common mycorrhizal networks improve survival and mediate facilitative plant interactions among Andropogon gerardii seedlings under drought stress

   https://doi.org/10.1007/s00572-025-01181-z  

   Russell, Margaret; Řezáčová, Veronika; Miller, Kirby Shane; Nardi, Wynter Helene; Brown, Morgan; Weremijewicz, Joanna (February 2025, Mycorrhiza)

   Under drought conditions, arbuscular mycorrhizal (AM) fungi may improve plant performance by facilitating the movement of water through extensive hyphal networks. When these networks interconnect neighboring plants in common mycorrhizal networks (CMNs), CMNs are likely to partition water among many individuals. The consequences of CMN-mediated water movement for plant interactions, however, are largely unknown. We set out to examine CMN-mediated interactions amongAndropogon gerardiiseedlings in a target-plant pot experiment, with watering (watered or long-term drought) and CMN status (intact or severed) as treatments. Intact CMNs improved the survival of seedlings under drought stress and mediated positive, facilitative plant interactions in both watering treatments. Watering increased mycorrhizal colonization rates and improved P uptake, particularly for large individuals. Under drought conditions, improved access to water most likely benefited neighboring plants interacting across CMNs. CMNs appear to have provided the most limiting resource within each treatment, whether P, water, or both, thereby improving survival and growth. Neighbors near large, photosynthate-fixing target plants likely benefited from their establishment of extensive hyphal networks that could access water and dissolved P within soil micropores. In plant communities, CMNs may be vital during drought, which is expected to increase in frequency, intensity, and length with climate change. 

   more » « less