Functional group composition and defoliation intensity affect differentially community invasibility according to exotic species ontogenetic stage

Functional group composition and defoliation intensity affect differentially community invasibility according to exotic species ontogenetic stage | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Functional group composition and defoliation intensity affect differentially community invasibility according to exotic species ontogenetic stage María Grisel Longo, Pedro Maximiliano Tognetti, Juan Manuel Piñeiro-Guerra, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7697211/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Apr, 2026 Read the published version in Biological Invasions → Version 1 posted 5 You are reading this latest preprint version Abstract Functional group composition can positively influence plant community invasibility through niche vacancy when the resident community does not sufficiently overlap with the invaders. Phenology plays a key role in determining functional group composition, as it defines the temporal scale on which niche overlap occurs. Defoliation may regulate the effect of functional group composition by releasing resources, resulting in interactive effects. In a manipulative experiment, we assembled native communities with different functional group compositions: perennial warm- and cool-season grasses growing either separately or together. These communities were subjected to two defoliation regimes to test the hypothesis that niche overlap determines the invasion success of Lolium multiflorum, an annual grass belonging to a functional group under-represented in the native flora of the region. We also hypothesized that higher defoliation intensity would increase community invasibility, promoting invasion and reducing the differences observed between communities under lower defoliation intensity. We evaluated this in two ontogenetic stages of the invader by counting seedlings and measuring above-ground biomass at the end of the growing season. The evidence shows that community invasibility is mediated by functional group composition through phenological overlap, although priority effects were also important. Defoliation intensity promoted seedling establishment similarly across all communities but did not affect the resulting above-ground biomass at the end of the growing season. Instead, it negatively impacted the performance of the invader growing in monoculture. Considering the variable effects on each ontogenetic stage is important for developing targeted management strategies at the appropriate temporal scale. Lolium multiflorum phenological overlap microcosm grassland Full Text Supplementary Files LongoetalSupplementaryInformation.pdf Cite Share Download PDF Status: Published Journal Publication published 17 Apr, 2026 Read the published version in Biological Invasions → Version 1 posted Reviewers agreed at journal 18 Oct, 2025 Reviewers invited by journal 13 Oct, 2025 Editor invited by journal 27 Sep, 2025 Editor assigned by journal 24 Sep, 2025 First submitted to journal 23 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7697211","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":529033491,"identity":"c2d05d30-ebd5-461a-9acf-8ce32664eebb","order_by":0,"name":"María Grisel 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