Do birds of a feather disperse plants together?

Abstract

1. Dispersal of propagules by waterbirds is thought to be important for wetland plants because of the abundance of birds and their frequent movements among aquatic habitats. Differences in bird characteristics (size, movement, feeding ecology) were expected to lead to different outcomes for plant dispersal. 2. We investigated heterogeneity in plant dispersal by ducks (Anas superciliosa, Anas gracilis, Anas castanea). We calculated the probability of transport of viable seeds by germinating propagules retrieved from feathers and feet (epizoochory) and the contents of the oesophagus, gizzard and lower gut (endozoochory). 3. The abundance and richness of seeds carried internally and externally did not differ among sympatric bird species. We used estimates from the literature of movements of Anas species to approximate dispersal kernels for the transport of plant propagules. 4. Heterogeneity in the abundance and movement ecology of disperser species will result in differing patterns and degrees of connectivity for wetland plant metacommunities. Sedentary waterfowl are likely to have an important role in replenishing propagules and connecting aquatic metacommunities over small distances. Nomadic waterfowl may facilitate long-distance dispersal. We discuss the implications of differences between duck species in movement patterns for connectivity of aquatic plant metacommunities across landscapes.

Seed dispersal by waterbirds in southern Africa: comparing the roles of ectozoochory and endozoochory

“…At least one intact propagule was found in 37% of the ectozoochory samples. This proportion was approximately double that found in other recent studies investigating ectozoochory (Brochet et al ., ; Raulings et al ., ). External transport is usually a rare mechanism and is the dominant dispersal mode in only 5% of extant plant species (Sorensen, ); the high proportion of ‘positive’ ectozoochory samples was thus surprising.…”

“…() and Raulings et al . () provide Australian examples. In this article, we present the first quantitative analysis of the seed dispersal potential of waterbirds anywhere in Africa.…”

Environmental opportunities and constraints in the reproduction and dispersal of aquatic plants

“…For example, Darwin noticed in 'On the Origin of Species by means of Natural Selection' (Darwin, 1859) that the dispersal of seeds and vegetative fragments on the plumage and muddy feet of water-fowl can explain the wide range of some freshwater plants. By germinating propagules retrieved from feathers and feet (epizoochory) and the contents of the oesophagus, gizzard and lower gut (endozoochory), Raulings et al (2011) found that sedentary waterfowl are likely to have an important role in replenishing propagules and connecting aquatic metacommunities over small distances. Nomadic waterfowl may facilitate long-distance dispersal.…”

Evaluating the potential for weed seed dispersal based on waterfowl consumption and seed viability

“…Some of this expansion can be attributed to the movement of seed through machinery, seed and feed . However, waterfowl have also been implicated, as they have demonstrated the ability to disperse wetland plant seeds over long distances . The abundance of waterfowl, their widespread distribution, as well as their high frequency of movement within and between habitats could prove crucial for the exchange of plant seed via waterfowl dispersal …”