Salinity mediates ecosystem impacts of an invasive macrophyte across an aquatic continuum

Salinity mediates ecosystem impacts of an invasive macrophyte across an aquatic continuum | 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 Salinity mediates ecosystem impacts of an invasive macrophyte across an aquatic continuum Leticia da Silva Brito, Heliana Teixeira, Daniel Crespo, Ana I Lillebø This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9227442/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract The ecological impacts of invasive species are increasingly recognized as context-dependent, yet the role of environmental gradients in shaping these effects remains poorly understood. This is particularly relevant in transitional aquatic ecosystems, where salinity gradients can constrain plant performance and alter ecosystem functioning. We investigated how salinity influences the functional role of the invasive macrophyte Pontederia crassipes by quantifying growth, nutrient uptake, and decomposition dynamics across a freshwater–marine continuum. Using a combination of mesocosm experiments (0–5 g L⁻¹) and in-situ litterbag assays along a natural salinity gradient (0–32 g L⁻¹), we assessed how key processes linked to ecosystem functioning vary across environmental conditions. We found that plant growth and nutrient uptake declined with increasing salinity, whereas decomposition rates increased markedly along with the gradient. These contrasting responses indicate a shift in the functional role of the species, from nutrient retention in freshwater systems to enhanced nutrient release under more saline conditions. Our results demonstrate that environmental gradients strongly modulate the ecosystem impacts of invasive macrophytes, highlighting salinity as a key driver of transitions between ecosystem service provision and ecosystem degradation. This context dependency has important implications for predicting invasion impacts and for managing transitional aquatic ecosystems. Pontederia crassipes mesocosm decomposition invasive alien species ecosystem service disservice Full Text Supplementary Files SupplementaryMaterial.doc Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 28 Apr, 2026 Reviewers invited by journal 09 Apr, 2026 Editor invited by journal 26 Mar, 2026 Editor assigned by journal 26 Mar, 2026 First submitted to journal 25 Mar, 2026 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. 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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-9227442","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":620139170,"identity":"860061bc-1837-493f-8f95-4b23fd80c3bf","order_by":0,"name":"Leticia da Silva 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