A predatory waterbird as a vector of plant seeds and aquatic invertebrates

Omnivorous waterbirds play an important role in aquatic ecosystems as dispersal vectors via direct ingestion, transportation, and egestion of plant invertebrate propagules (i.e. endozoochory). Predatory birds also have the potential to disperse plants invertebrates that were first carried internally or externally by their prey animals. However, contribution predatory waterbird species propagule remains understudied. We chose grey heron Ardea cinerea (Ardeidae) study within among ecosystems. hypothesised that: (1) herons a wide variety propagules, from different habitats, with morphologies syndromes), including both native alien species; (2) are ingested primary (i.e., secondary dispersers); (3) pellets show similar abundance richness across widespread range. collected 73 regurgitated containing undigestible 12 locations U.K. The Netherlands, examined taxonomic diversity seeds, remains. Pellets dominated mammal hairs (99% volume), bones confirmed ingestion small mammals (prevalence 38%, e.g. water voles Arvicola amphibius), fish (14%), amphibians (6%). A total 266 intact seeds recovered 71% pellets, representing 50 taxa 17 families, Cotula coronopifolia. cumulative number dispersed was lower at higher latitudes. Eight recorded had not previously been waterbirds, only three endozoochorous syndrome. Plant Caryophyllaceae, Cyperaceae, Juncaceae, Poaceae, 24 littoral zone (Ellenberg moisture values 7–12) 21 terrestrial 4–6). Intact found 30% Cladocera (Daphniidae) Bryozoa (including Plumatella casmiana). Our results demonstrate widely north-western Europe. Herons regurgitate contain for which along is likely underlying mechanism either attached digestive systems various prey). findings showcase invertebrates, how they may facilitate connectivity between freshwater habitats.