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Germination Response of the Freshwater Invasive Iris pseudacorus to Brackish and Marine Salinity as Well as Implications for Coastal Invasion

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Abstract

Clarifying the conditions in which a species can germinate helps elucidate dispersal and establishment patterns. Conventionally considered a freshwater species, evidence indicates that the invasive Yellow flag iris (Iris pseudacorus), originally from North Africa, East Asia and Europe, tolerates saline conditions. Clarifying how water-dispersed I. pseudacorus seeds respond to seawater immersion is critical to understanding marine dispersal and invasion risk for coastal habitats. Accordingly, we evaluated the impact of salinity on the germination of I. pseudacorus. Using seeds from marine and freshwater I. pseudacorus populations, we assessed how the duration of immersion (15, 30, 60, and 90 days) in varying salinities (0, 13–15, 33–35 practical salinity units [PSU]) affected germination, and whether immersion in freshwater following saline exposure impacted germination or seed viability. Seeds sourced from freshwater consistently outperformed seeds from the marine population. Neither salinity concentration nor immersion duration had a statistically significant impact on germination, and nearly all seeds remained buoyant in marine saltwater (33–35 PSU) for 90 days. Saline immersion and germination conditions inhibited germination unless seeds received a freshwater recovery. The freshwater population of seeds had statistically significantly thicker seed coats, but there was no discernible difference in mean seed weight. Seeds from both populations remained viable after prolonged salinity exposure (90–165 days). We posit that observed differences in germination between the two populations may arise from seed dormancy mechanisms rather than seed fitness. Our results suggest that I. pseudacorus seeds could disperse vast distances through the marine environment, possibly habitat-hopping to reach increasingly suitable ecosystems.

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Data Availability

The datasets generated and analyses performed as part of this study are available from the corresponding author upon reasonable request.

References

  • Adam P (1977) On the phytosociological status of Juncus maritimus on British saltmarshes. Vegetatio 35:81–94

    Article  Google Scholar 

  • Arditti J, Pray TR (1969) Dormancy factors in iris (Iridaceae) seeds. American Journal of Botany 56:254–0

    Article  CAS  Google Scholar 

  • Ashe A, Colot V, Oldroyd BP (2021) How does epigenetics influence the course of evolution? Philosophical Transactions of the Royal Society B: Biological Sciences 376:20200111

    Article  CAS  Google Scholar 

  • Barbet-Massin M, Rome Q, Villemant C et al (2018) Can species distribution models really predict the expansion of invasive species? PloS One 13:e0193085

    Article  PubMed  PubMed Central  Google Scholar 

  • Bewley JD, Black M (2013) Seeds: physiology of development and germination. Springer Science & Business Media, NewYork

    Book  Google Scholar 

  • Blumenthal A, Lerner HR, Werker E et al (1986) Germination preventing mechanisms in iris seeds. Annals of Botany 58:551–561

    Article  Google Scholar 

  • Brasseale E, Grason EW, Mcdonald PS et al (2019) Larval transport modeling support for identifying population sources of European Green Crab in the Salish Sea. Estuaries and Coasts 42:1586–1599

    Article  CAS  Google Scholar 

  • Chang ER, Veeneklaas RM, Bakker JP (2007) Seed dynamics linked to variability in movement of tidal water. Journal of Vegetation Science 18:253–262

    Article  CAS  Google Scholar 

  • Chang ER, Veeneklaas RM, Buitenwerf R et al (2008) To move or not to move: Determinants of seed retention in a tidal marsh. Functional Ecology 22:720–727

    Article  Google Scholar 

  • Checkley DM, Barth JA (2009) Patterns and processes in the California current system. Progress in Oceanography 83:49–64

    Article  Google Scholar 

  • Chen L (2019) Invasive plants in coastal wetlands: patterns and mechanisms. In: An S, Verhoeven J (eds) Wetlands: ecosystem services, restoration and wise use. Springer, Cham, pp 97–128. https://doi.org/10.1007/978-3-030-14861-4_5

  • Coops H, Van Der Velde G (1995) Seed dispersal, germination and seedling growth of six helophyte species in relation to water-level zonation. Freshwater Biology 34:13–20

    Article  Google Scholar 

  • Cottrell HJ (1947) Tetrazolium salt as a seed germination indicator. Nature 159:748–748

    Article  CAS  PubMed  Google Scholar 

  • Crocker W (1906) Role of seed coats in delayed germination. Contributions from the Hull Botanical Laboratory. LXXXV. Botanical Gazette 42:0265–0291

    Article  Google Scholar 

  • Dawson W, Moser D, Van Kleunen M et al (2017) Global hotspots and correlates of alien species richness across taxonomic groups. Nature Ecology & Evolution 1:0186

    Article  Google Scholar 

  • Donatelli C, Duran-Matute M, Grawe U et al (2022) Residual circulation and freshwater retention within an event-driven system of intertidal basins. Journal of Sea Research 186:102242

    Article  Google Scholar 

  • Dudgeon D, Arthington AH, Gessner MO et al (2006) Freshwater biodiversity: Importance, threats, status and conservation challenges. Biological reviews of the Cambridge Philosophical Society 81:163–182

    Article  PubMed  Google Scholar 

  • Dyer AR, Brown CS, Espeland EK et al (2010) The role of adaptive trans-generational plasticity in biological invasions of plants. Evolutionary Applications 3:179–192

    Article  PubMed  PubMed Central  Google Scholar 

  • Ens NJ, Harvey B, Davies MM et al (2022) The Green Wave: Reviewing the environmental impacts of the invasive European green crab (Carcinus maenas) and potential management approaches. Environmental Reviews 30:306–322

    Article  CAS  Google Scholar 

  • Epanchin-Niell RS (2017) Economics of invasive species policy and management. Biological Invasions 19:3333–3354

    Article  Google Scholar 

  • França-Neto JDB, Krzyzanowski FC (2019) Tetrazolium: An important test for physiological seed quality evaluation. Journal of Seed Science 41:359–366

    Article  Google Scholar 

  • Gallardo B, Clavero M, Sanchez MI et al (2016) Global ecological impacts of invasive species in aquatic ecosystems. Global Change Biology 22:151–163

    Article  PubMed  Google Scholar 

  • Gallego-Tévar B, Grewell BJ, Whitcraft CR et al (2022) Contrasted impacts of Yellow flag iris (Iris pseudacorus) on plant diversity in tidal wetlands within its native and invaded distribution ranges. Diversity 14:326

    Article  Google Scholar 

  • Gaskin JF, Pokorny ML, Mangold JM (2016) An unusual case of seed dispersal in an invasive aquatic; Yellow flag iris (Iris pseudacorus). Biological Invasions 18:2067–2075

    Article  Google Scholar 

  • Gervazoni P, Sosa A, Franceschini C et al (2020) The alien invasive Yellow flag (Iris pseudacorus L.) in Argentinian wetlands: Assessing geographical distribution through different data sources. Biological Invasions 22:3183–3193

    Article  Google Scholar 

  • Gerwing TG, Thomson HM, Brouard-John EK et al (2021) Observed dispersal of invasive Yellow flag iris (Iris pseudacorus) through a saline marine environment and growth in a novel substrate, shell hash. Wetlands 41:1–6

    Article  Google Scholar 

  • Gillard MB, Castillo JM, Mesgaran MB et al (2021) High aqueous salinity does not preclude germination of invasive Iris pseudacorus from estuarine populations. Ecosphere 12:e03486

    Article  Google Scholar 

  • Gillard MB, Castillo JM, Mesgaran MB et al (2022) Germination niche breadth of invasive Iris pseudacorus (L.) suggests continued recruitment from seeds with global warming. American Journal of Botany 109:1108–1119

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  • Gillham ME (1957) Coastal vegetation of Mull and Iona in relation to salinity and soil reaction. Journal of Ecology 45:757–778

    Article  Google Scholar 

  • González MB (2019) Adaptation of halophytes to different habitats. In: Jimenez-Lopez JC (ed) Seed dormancy and germination. IntechOpen, pp 1–23. https://doi.org/10.5772/intechopen.87056

  • Green SJ, Grosholz ED (2021) Functional eradication as a framework for invasive species control. Frontiers in Ecology and the Environment 19:98–107

    Article  Google Scholar 

  • Grewell BJ, Gallego-Tevar B, Gillard MB et al (2021) Salinity and inundation effects on Iris pseudacorus: Implications for tidal wetland invasion with sea level rise. Plant and Soil 466:275–291

    Article  CAS  Google Scholar 

  • Grewell BJ, Gallego-Tévar B, Bárcenas-Moreno G et al (2023) Phenotypic trait differences between Iris pseudacorus in native and introduced ranges support greater capacity of invasive populations to withstand sea level rise. Diversity and Distributions 29:834–848

    Article  Google Scholar 

  • Guja LK, Merritt DJ, Dixon KW (2010) Buoyancy, salt tolerance and germination of coastal seeds: Implications for oceanic hydrochorous dispersal. Functional Plant Biology 37:1175–1186

    Article  Google Scholar 

  • Gul B, Ansari R, Flowers TJ et al (2013) Germination strategies of halophyte seeds under salinity. Environmental and Experimental Botany 92:4–18

    Article  CAS  Google Scholar 

  • Hanhijärvi AM, Fagerstedt KV (1994) Comparison of the effect of natural and experimental anoxia on carbohydrate and energy metabolism in Iris pseudacorus rhizomes. Physiologia Plantarum 90:437–444

    Article  Google Scholar 

  • Havel JE, Kovalenko KE, Thomaz SM et al (2015) Aquatic invasive species: Challenges for the future. Hydrobiologia 750:147–170

    Article  PubMed  PubMed Central  Google Scholar 

  • Hickey BM (1979) The California current system—hypotheses and facts. Progress in Oceanography 8:191–279

    Article  Google Scholar 

  • Hintz WD, Relyea RA (2019) A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters. Freshwater Biology 64:1081–1097

    Article  Google Scholar 

  • Infante-Izquierdo MD, Castillo JM, Grewell BJ et al (2019) Differential effects of increasing salinity on germination and seedling growth of native and exotic invasive cordgrasses. Plants 8:372

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  • Jaca TP, Mkhize V (2015) Distribution of Iris pseudacorus (Linnaeus, 1753) in South Africa. BioInvasions Records 4:249–253

    Article  Google Scholar 

  • Kcnwcp (2020) King county noxious weed control program best management practices: yellow-flag iris (Iris pseudacorus Iridaceae). In: WaLRD King County Department of Natural Resources and Parks, Washington (ed) King County Department of Natural Resources and Parks, Water and Land Resources Division, Washington

  • Khangaonkar T, Long W, Xu W (2017) Assessment of circulation and inter-basin transport in the Salish Sea including Johnstone Strait and Discovery Islands pathways. Ocean Modelling 109:11–32

    Article  Google Scholar 

  • Kleyheeg E, Claessens M, Soons MB (2018) Interactions between seed traits and digestive processes determine the germinability of bird-dispersed seeds. PloS One 13:e0195026

    Article  PubMed  PubMed Central  Google Scholar 

  • Kołodziejek J, Patykowski J, Wala M (2019) Dormancy, germination, and sensitivity to salinity stress in five species of Potentilla (Rosaceae). Botany 97:452–462

    Article  Google Scholar 

  • Koutstaal BP, Markusse MM, de Munck W (1987) Aspects of seed dispersal by tidal movement. In: Huiskes AH, Blom CWPM, Rozema J (eds) Vegetation between land and sea: structure and processes. Junk, Dordrecht, pp 226–235

  • Larson ER, Graham BM, Achury R et al (2020) From eDNA to citizen science: emerging tools for the early detection of invasive species. Frontiers in Ecology and the Environment 18:194–202

    Article  Google Scholar 

  • Leach S (2000) The saltmarshes of coll and tiree. Botanical Journal of Scotland 52:65–78

    Article  Google Scholar 

  • Liu R, Wang L, Tanveer M et al (2018) Seed heteromorphism: An important adaptation of halophytes for habitat heterogeneity. Frontiers in Plant Science 9:1515

    Article  PubMed  PubMed Central  Google Scholar 

  • Marbán LM, Zalba SM (2019) When the seeds go floating in: a salt marsh invasion. Estuarine, Coastal and Shelf Science 231:106442

  • Melo-Merino SM, Reyes-Bonilla H, Lira-Noriega A (2020) Ecological niche models and species distribution models in marine environments: A literature review and spatial analysis of evidence. Ecological Modelling 415:108837

    Article  Google Scholar 

  • Miller AL (2010) AOSA/SCST tetrazolium testing handbook. Association of Official Seed Analysts (AOSA) & Society of Commercial Seed Technologists (SCST), Moline, IL

  • Mopper S, Wiens KC, Goranova GA (2016) Competition, salinity, and clonal growth in native and introduced irises. American Journal of Botany 103:1575–1581

    Article  PubMed  Google Scholar 

  • Munishi LK, Ngondya IB (2022) Realizing UN decade on ecosystem restoration through a nature-based approach: A case review of management of biological invasions in protected areas. PLOS Sustainability and Transformation 1:e0000027

    Article  Google Scholar 

  • Nilsson C, Brown RL, Jansson R et al (2010) The role of hydrochory in structuring riparian and wetland vegetation. Biological Reviews 85:837–858

    Article  PubMed  Google Scholar 

  • Pan Y, Garcia-Giron J, Iversen LL (2023) Global change and plant-ecosystem functioning in freshwaters. Trends in Plant Science 28(6):646–660. https://doi.org/10.1016/j.tplants.2022.12.013

  • Rahel FJ, Olden JD (2008) Assessing the effects of climate change on aquatic invasive species. Conservation Biology 22:521–533

    Article  PubMed  Google Scholar 

  • Ranal MA, Santana DGD (2006) How and why to measure the germination process? Brazilian Journal of Botany 29:1–11

    Article  Google Scholar 

  • Reijers VC, Lammers C, De Rond AJA et al (2020) Resilience of beach grasses along a biogeomorphic successive gradient: Resource availability vs. clonal integration. Oecologia 192:201–212

    Article  PubMed  Google Scholar 

  • Ridley HN (1930) The dispersal of plants throughout the world. L. Reeve & Co., Ashford

    Google Scholar 

  • Sala OE, Chapin FS, 3rd, Armesto JJ et al (2000) Global biodiversity scenarios for the year 2100. Science 287:1770–1774

  • Schluter U, Crawford RM (2001) Long-term anoxia tolerance in leaves of Acorus calamus L. and Iris pseudacorus L. Journal of Experimental Botany 52:2213–2225

    Article  CAS  PubMed  Google Scholar 

  • Simberloff D (2014) Biological invasions: What’s worth fighting and what can be won? Ecological Engineering 65:112–121

    Article  Google Scholar 

  • Singh K, Byun C (2023) Ecological restoration after management of invasive alien plants. Ecological Engineering 197:107122

    Article  Google Scholar 

  • Solohin E, Widney SE, Craft CB (2020) Declines in plant productivity drive loss of soil elevation in a tidal freshwater marsh exposed to saltwater intrusion. Ecology 101:e03148

    Article  PubMed  Google Scholar 

  • Song J, Wang BS (2015) Using euhalophytes to understand salt tolerance and to develop saline agriculture: Suaeda salsa as a promising model. Annals of Botany 115:541–553

    Article  CAS  PubMed  Google Scholar 

  • Song J, Shi WW, Liu RR et al (2017) The role of the seed coat in adaptation of dimorphic seeds of the euhalophyte Suaeda salsa to salinity. Plant Species Biology 32:107–114

    Article  Google Scholar 

  • Stoltz LP (1968) Iris seed dormancy. Physiologia Plantarum 21:1328–1331

    Article  Google Scholar 

  • Sutherland WJ (1990) Iris Pseudacorus L. Journal of Ecology 78:833–848

    Article  Google Scholar 

  • Sutherland WJ, Walton D (1990) The changes in morphology and demography of Iris pseudacorus L. at different heights on a saltmarsh. Functional Ecology 4:655–659

    Article  Google Scholar 

  • Team RC (2022) R: a language and environment for statistical computing. In: RC Team (ed) R Foundation for Statistical Computing. Vienna, Austria

  • Thomaz SM, Kovalenko KE, Havel JE et al (2015a) Aquatic invasive species: General trends in the literature and introduction to the special issue. Hydrobiologia 746:1–12

    Article  Google Scholar 

  • Thomaz SM, Mormul RP, Michelan TS (2015b) Propagule pressure, invasibility of freshwater ecosystems by macrophytes and their ecological impacts: A review of tropical freshwater ecosystems. Hydrobiologia 746:39–59

    Article  Google Scholar 

  • Thomson HM, Davies MM, Lawn PTES et al (2021) Spread of an aquatic invasive plant, Iris pseudacorus, following replacement of a hydraulic structure. Ecological Restoration 39:238–246

    Article  Google Scholar 

  • Thomson HM, Shackelford N, Gerwing TG (2022) Observation of the freshwater invasive, Yellow flag iris (Iris pseudacorus L.) reproducing in marine habitat, isolated from perennial freshwater inputs. Pacific Conservation Biology 29:364–365

    Article  Google Scholar 

  • Tootoonchi M, Gettys LA (2019) Testing salt stress on aquatic plants: Effect of salt source and substrate. Aquatic Ecology 53:325–334

    Article  CAS  Google Scholar 

  • Ungar IA (1987) Population ecology of halophyte seeds. The Botanical Review 53:301–334

    Article  Google Scholar 

  • Van Der Stocken T, Wee AKS, De Ryck DJR et al (2019) A general framework for propagule dispersal in mangroves. Biological Reviews 94:1547–1575

    Article  PubMed  Google Scholar 

  • Van Zandt PA, Mopper S (2004) The effects of maternal salinity and seed environment on germination and growth in Iris hexagona. Evolutionary Ecology Research 6:813–832

    Google Scholar 

  • Van Zandt PA, Tobler MA, Mouton E et al (2003) Positive and negative consequences of salinity stress for the growth and reproduction of the clonal plant, Iris hexagona. Journal of Ecology 91:837–846

  • Young SL, Hamerlynck EP (2023) Patterning ecological restoration after weeds. Restoration Ecology 31:e13841

    Article  Google Scholar 

  • Zhao YT, Wang GD, Zhao ML et al (2022) How soil salinization and alkalinization drive vegetation change in salt-affected inland wetlands. Plant and Soil 480:571–581

    Article  CAS  Google Scholar 

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Funding

We acknowledge the support of NSERC, the Natural Sciences and Engineering Research Council of Canada [funding reference number SRQ412903].

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  1. School of Environmental Studies, University of Victoria, Victoria, BC, Canada

    Hanna M. Thomson, Nancy Shackelford, Miranda A. Gilbert & Travis G. Gerwing

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  1. Hanna M. Thomson
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  4. Travis G. Gerwing
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Contributions

All authors contributed to the study's conception and design. HMT and MAG performed study implementation and data collection. HMT conducted data analyses with support from NS and TGG. The first complete draft of the manuscript was written by HMT. NS, MAG, and TGG helped edit and refine subsequent manuscript versions. All authors read and approved the final manuscript.

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Correspondence to Hanna M. Thomson.

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Thomson, H.M., Shackelford, N., Gilbert, M.A. et al. Germination Response of the Freshwater Invasive Iris pseudacorus to Brackish and Marine Salinity as Well as Implications for Coastal Invasion. Wetlands 44, 36 (2024). https://doi.org/10.1007/s13157-024-01792-w

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