Migratory geese allow plants to disperse to cooler latitudes across the ocean

Abstract

AimHow plants can disperse in response to global change is a critical question, yet major knowledge gaps persist about long‐distance dispersal (LDD) mechanisms. We studied the potential a migratory waterfowl has for LDD of flowering plants via gut passage of seeds (endozoochory), comparing spring and autumn migration.LocationUnited Kingdom and Iceland.TaxonPink‐footed Goose (Anser brachyrhynchus, Baillon) and Angiosperma.MethodsWe studied endozoochory by Pink‐footed geese migrating within and between the UK and Iceland by faecal sampling and GPS tracking. We collected 614 faecal samples from 14 areas in the UK and one in Iceland. Using GPS tracks to and from these areas, we estimated how far seeds can be dispersed by Pink‐footed geese, and where to or from.ResultsWe recorded 5507 intact seeds of 35 species (27 terrestrial) from 15 plant families, with lower seed abundance per dropping when birds were migrating northwards in the UK during spring than upon their arrival in autumn. Species richness of plant seeds was highest in Iceland and in autumn. Only four plant species dispersed had an “endozoochory syndrome”. GPS movements showed that seeds retained in guts for up to 24 h can be readily dispersed in both directions between the UK and Iceland, with maximum distances exceeding 2000 km, as well as between UK localities separated by 100 s of km. Movements northwards of ≤400 km were even recorded in autumn. While at stopover sites, daily movements between roost and feeding sites often exceed 20 km.Main ConclusionsPink‐footed geese are LDD vectors for plants previously assumed to lack an LDD mechanism. Spring migration is not the only period when geese move plants to cooler latitudes. The pink‐footed goose can allow terrestrial and aquatic plants to cross the ocean and to keep pace with climate change.

Plant traits associated with seed dispersal by ducks and geese in urban and natural habitats

“…We recorded many species as a single seed, and increasing sampling effort would likely detect many additional plant species whose seeds are carried in waterfowl guts. These vectors may be vital to allow plants to modify their distributions in response to global change (Lovas‐Kiss et al., 2023; Nuñez et al., 2023; Urgyán et al., 2023).…”

“…Since the peak in endozoochory rates in late summer was not strongly pronounced, instead continuing into autumn, our results also suggest that endozoochory can occur at high rates for months after seed production, as shown for ducks in central and southern Europe (Brochet et al., 2010; Figuerola et al., 2003; Urgyán et al., 2023). Hence, seed dispersal by waterfowl is not strongly coupled to the phenology of fruit production in a manner comparable to frugivory (González‐Varo et al., 2021), and this likely favours poleward plant dispersal in response to climate change (Lovas‐Kiss et al., 2023; Urgyán et al., 2023).…”

“…These vectors may be vital to allow plants to modify their distributions in response to global change (Lovas-Kiss et al, 2023;Nuñez et al, 2023;Urgyán et al, 2023).…”

“…As opportunistic habitat generalists, they ingest and disperse an abundance of seeds from a wide range of plant species (Kleyheeg et al., 2017; Soons et al., 2016; Urgyán et al., 2023). Recent studies demonstrate that geese are also important seed vectors in Europe (Almeida et al., 2022; Hattermann et al., 2019; Lovas‐Kiss et al., 2023; Navarro‐Ramos et al., 2024), but there are no studies comparing plants dispersed by ducks and geese in the same habitats, or their trait composition.…”

Overlooked seed‐dispersal modes and underestimated distances

“…Endozoochory by wild and domestic ungulates has been studied in broadleaved and mixed temperate forests, Mediterranean dehesas, grasslands and coastal habitats (see appendix 1 and tab. A1 in Albert et al, 2015), while endozoochory by waterbirds has been studied in permanent and temporary wetlands, grasslands and agricultural habitats (Almeida et al, 2022;Lovas-Kiss et al, 2023). Thus, endozoochory by nonfrugivorous seed dispersers is not only important across plant taxa but also across habitat types.…”