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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. 

Abstract 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. 

Course-based undergraduate research experiences (CUREs) are an effective way to integrate research into an undergraduate science curriculum and extend research experiences to a large, diverse group of early-career students. We developed a biology CURE at the University of Miami (UM) called the UM Authentic Research Laboratories (UMARL), in which groups of first-year students investigated novel questions and conducted projects of their own design related to the research themes of the faculty instructors. Herein, we describe the implementation and student outcomes of this long-running CURE. Using a national survey of student learning through research experiences in courses, we found that UMARL led to high student self-reported learning gains in research skills such as data analysis and science communication, as well as personal development skills such as self-confidence and self-efficacy. Our analysis of academic outcomes revealed that the odds of students who took UMARL engaging in individual research, graduating with a degree in science, technology, engineering, or mathematics (STEM) within 4 years, and graduating with honors were 1.5–1.7 times greater than the odds for a matched group of students from UM’s traditional biology labs. The authenticity of UMARL may have fostered students’ confidence that they can do real research, reinforcing their persistence in STEM.