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Avian vectors, such as ducks, swans and geese, are important dispersers of plant propagules. Until recently, it was thought that small vegetative propagules were reliant on adherence to vectors and are unlikely to survive passage through the avian digestive tract. Here, we conclusively demonstrate that metabolically active angiosperms can survive p...
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Co-pollution of antibiotics and heavy metal copper (Cu) is common in freshwater environments because of their wide use as antimicrobial agents, especially in aquaculture. However, the toxic effects of coexisting antibiotics and heavy metals on aquatic plants remain unclear. This study investigated the effect of four antibiotics (i.e., enrofloxacin,...
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... However, woody plants with larger seeds are also present (Rolon et al., 2010;Wiesbauer et al., 2008). Although wetland plants are typically assigned to abiotic syndromes (Julve, 1998;Lososová et al., 2023), empirical studies have shown that birds and mammals can disperse whole plants (Paolacci et al., 2023;Silva et al., 2018), seeds (Flaherty et al., 2017;Silva et al., 2020) and spores in and between wetlands. ...
... This habit may increase establishment success, and hence dispersal quality, for propagules of aquatic plants (van Leeuwen et al., 2022). It is also favourable for dispersal of wholeplants (Paolacci et al., 2023;Silva et al., 2018) such as the entire free-floating duckweed (Spirodela intermedia) recovered from nutria faeces ( Figure 6a). Duckweeds are part of the diet of both rodents (Borgnia et al., 2000;Guichón et al., 2003;Moreira et al., 2013), ...
The role of large frugivores in the dispersal of tropical trees has been well‐studied, whereas the importance of the world's largest rodents for plant dispersal has previously been ignored. We studied plant dispersal by gut passage (endozoochory) in Neotropical wetlands by the largest extant rodent, the capybara Hydrochoerus hydrochaeris. We compared it with another of the world's 10 largest rodents, the nutria or coypu Myocastor coypus.
We collected 96 faecal samples (50 capybara, 46 nutria) from 10 sites within the Taim Ramsar site in southern Brazil, and extracted intact propagules from 10 g subsamples. Propagules from 27 plant taxa (24 angiosperms, and three aquatic ferns) were recovered, representing 13 plant families. Whole Spirodela (duckweed) plants were dispersed. Seeds from 14 angiosperm taxa were germinated in the laboratory.
Taxonomic composition of propagules was significantly different for the two mammals, but propagule size was not. Capybara dispersed more terrestrial propagules per sample, and nutrias more aquatic propagules. When total faecal production was taken into account, an estimated 1025 propagules (including 133 fern spores) were dispersed by each capybara per day, compared with 691 propagules for nutrias (including 566 fern spores). Capybaras have larger home ranges and likely dispersed plants over a greater distance.
Synthesis: This is the first demonstration that rodents disperse aquatic pteridophytes as well as flowering plants. Our results suggest that capybaras and nutrias play important, complementary roles in dispersing a variety of aquatic and terrestrial plant species within Neotropical wetlands. Our study indicates that the role of herbivorous mammals as vectors of plants with small seeds and non‐fleshy fruits has been overlooked in the neotropics and that defaunation of large herbivores can have negative consequences, in a manner similar to that previously highlighted for frugivores.
... Considering the high mobility of ducks over both short distances (i.e. between water bodies) and long distances (i.e. migration), along with the high frequency of duck fecal events, endozoochory may be a major duckweed spread mechanism (Paolacci et al. 2023). The usual pathways for L. punctata introduction, namely aquarium trade, as a stowaway plant, and animal and boat transportation indicate the potential for multiple introductions and increased propagule pressure which makes widespread invasions such as that seen in the US more likely (Lockwood et al. 2009). ...
... Once dotted duckweed spreads, management becomes virtually impossible, as it reproduces asexually and has one of the fastest growth rates seen in higher plants (Ziegler et al., 2014). In addition, there are multiple introduction pathways, such as aquarium and garden trade (Neucker & Scheers, 2022), and deposition through waterfowl feces (Paolacci et al. 2023). Herbicide resistance developed by dotted duckweed (Koschnick et al 2006) is an additional factor that would hinder management actions. ...
Landoltia punctata is an invasive aquatic plant that has spread across the United States. Unlike native duckweeds, this species has developed herbicide resistance. As a result, invasion can lead to high management costs and the loss of recreational areas and natural habitats. The species has been recently found in Europe, and is also approaching the northern US border with Canada. We predicted the potential distribution of L. punctata in western Europe and Canada using presence-only data from the Global Biodiversity Information Facility as well as other literature records. We fit predictive models to this data using a Maxent approach. Since climate data based on surface lake water conditions are often more relevant to macrophytes than air temperature metrics, our models included both water and air temperature bioclimatic variables related to the life history of the species. Model comparisons confirmed a superior fit of lake temperatures to duckweed distribution records. The best fit model suggests a high habitat suitability for the species in most Western European countries and Western Canada. A moderate emission scenario suggests that in 2041 currently compatible areas will still be suitable, and that the Great Lakes region will become suitable. Preventive measures to avoid future spread of L. punctata are recommended in these locations to avoid impacts associated with this and similar duckweed species in Europe and the US.
... In addition to attachment to waterfowl body parts, living duckweed fronds were recently found to survive for several days and reproduce in duck feces. Considering the high mobility of ducks in short distances, such as roaming between water bodies, and long distances, such as in continental fall migrations, along with the high frequency of duck fecal events, endozoochory may be a major duckweed spread mechanism (Paolacci et al., 2023). The usual pathways for L. punctata introduction, namely aquarium trade, as a stowaway plant, and animal and boat transportation indicate the potential for multiple introductions, which makes widespread invasions such as that seen in the US more likely, as a result of propagule pressure (Lockwood, Cassey, & Blackburn, 2009). ...
Landoltia punctata is an invasive aquatic plant that has spread across the United States. Unlike native duckweeds, this species has developed herbicide resistance. As a result, invasion can lead to high management costs and the loss of recreational areas and natural habitats. The species has been recently found in Europe, and is also approaching the northern US border with Canada. We predicted the potential distribution of L. punctata in western Europe and Canada using presence-only data from the Global Biodiversity Information Facility as well as other literature records. We fit predictive models to this data using a Maxent approach. Since climate data based on surface lake water conditions are often more relevant to macrophytes than air temperature metrics, our models included both water and air temperature bioclimatic variables related to the life history of the species. Model comparisons confirmed a superior fit of lake temperatures to duckweed distribution records. The best fit model suggests a high habitat suitability for the species in most Western European countries and Western Canada. A moderate emission scenario suggests that in 2070 currently compatible areas will still be suitable, and that the Great Lakes region will become suitable. Preventive measures to avoid future spread of L. punctata are recommended in these locations to avoid impacts associated with this and similar duckweed species in Europe and the US.
... Earlier this year, a team from University College Cork added a flowering-plant example, albeit an extremely small one (Paolacci et al. 2023). They managed successfully to grow two species of duckweed from plantlets recovered from Mute Swan Cygnus olor faeces. ...
A semi-popular account of recent work on the role of waterbirds in plant dispersal in Britain.
... Lemna from feces of mute swans (Paolacci et al., 2023). Closely related Wolffia can also be dispersed by waterfowl endozoochory (Silva et al., 2018). ...
Ducks and geese are little studied dispersal vectors for plants lacking a fleshy fruit, and our understanding of the traits associated with these plants is limited. We analyzed 507 faecal samples of mallard ( Anas platyrhynchos ) and Canada goose ( Branta canadensis ) from 18 natural and urban wetlands in England, where they are the dominant resident waterfowl. We recovered 930 plant diaspores from 39 taxa representing 18 families, including 28 terrestrial and five aquatic species and four aliens. Mallards had more seeds and seed species per sample than geese, more seeds from barochory and hydrochory syndromes, and seeds that on average were larger and from plants with greater moisture requirements (i.e., more aquatic). Mallards dispersed more plant species than geese in natural habitats. Plant communities and traits dispersed were different between urban (e.g., more achenes) and natural (e.g., more capsules) habitats. Waterfowl can readily spread alien species from urban into natural environments but also allow native terrestrial and aquatic plants to disperse in response to climate heating or other global change. Throughout the temperate regions of the Northern Hemisphere, the mallard is accompanied by a goose (either the Canada goose or the greylag goose) as the most abundant waterfowl in urbanized areas. This combination provides a previously overlooked seed dispersal service for plants with diverse traits.
... Transport by birds can also occur by endozoochory, as fronds of Wo. columbiana, Le. minor, and Le. gibba were found to survive passage through the guts of waterfowl [35,36]. In time, repeated short-range relocation events can result in far-reaching dispersal of the fronds [2,37], and long-distance dispersal by birds may also occur [7,38]. ...
Duckweeds (Lemnaceae) are small, simply constructed aquatic higher plants that grow on or just below the surface of quiet waters. They consist primarily of leaf-like assimilatory organs, or fronds, that reproduce mainly by vegetative replication. Despite their diminutive size and inornate habit, duckweeds have been able to colonize and maintain themselves in almost all of the world’s climate zones. They are thereby subject to multiple adverse influences during the growing season, such as high temperatures, extremes of light intensity and pH, nutrient shortage, damage by microorganisms and herbivores, the presence of harmful substances in the water, and competition from other aquatic plants, and they must also be able to withstand winter cold and drought that can be lethal to the fronds. This review discusses the means by which duckweeds come to grips with these adverse influences to ensure their survival. Important duckweed attributes in this regard are a pronounced potential for rapid growth and frond replication, a juvenile developmental status facilitating adventitious organ formation, and clonal diversity. Duckweeds have specific features at their disposal for coping with particular environmental difficulties and can also cooperate with other organisms of their surroundings to improve their survival chances.
