Endozoochorous dispersal of aquatic plants: does seed gut passage affect plant performance?

Abstract

The ingestion of seeds by vertebrates can affect the germinability and/or germination rate of seeds. It is, however, unclear if an earlier germination as a result of ingestion affects later plant performance. For sago pondweed, Potamogeton pectinatus, the effects of seed ingestion by ducks on both germinability and germination rate have been previously reported from laboratory experiments. We performed an experiment to determine the effects of seed ingestion by ducks on germination, seedling survival, plant growth and asexual multiplication. Both at the start and end of the winter, seeds were fed to three captive shovelers (Anas clypeata) and planted outdoors in water-filled containers. Plant biomass and its allocation to vegetative parts (shoot and roots), tubers, and seeds were determined in autumn. More duck-ingested seeds than control (uningested) seeds germinated in early winter, but this difference disappeared for seeds planted in late winter, when the treatments were first stratified for 3 mo. None of the variables for measuring seedling survival and plant performance varied between treatments. Under our experimental conditions (no herbivory or competition), ingestion by ducks in early winter resulted in increased performance for seeds surviving gut passage due to enhanced seed germinability, without other costs or benefits for the seedlings.

Do macrophytes, diatoms and non-diatom benthic algae give redundant information? Results from a case study in Poland

“…Among others, macrophytes and algae can be dispersed by waterfowl (Figuerola et al, 2005;Charalambidou and Santamaria, 2005), and it has been shown previously that waterfowl selects habitat based on river structural characteristics (Johnson et al, 1996). A possible scenario is, therefore, that waterfowl will transport macrophytes, diatoms and non-diatom benthic algae between sites having similar structural characteristics.…”

Enhancement of local species richness in tundra by seed dispersal through guts of muskox and barnacle goose

“…This observation implies selective feeding on plant infructescences (not the least Polygonum viviparum bulbil spikes) and a rather fast and ineYcient digestion of plant material (consistent with Buchsbaum et al 1986). Geese have previously been shown to be important seed dispersers of aquatic plants (Charalambidou and Santamaría 2002;Clausen et al 2002;Figuerola et al 2005) but have only rarely been considered to be frugivores and seed dispersers of terrestrial plant seeds (but see Willson et al 1997). Although we did not investigate plant colonization following seed deposition in communities with vertebrate dung, our results show that seed dispersal by means of vertebrates potentially contributes to the generation and maintenance of plant community species richness.…”

Predicting Spatial Patterns of Plant Recruitment Using Animal-Displacement Kernels

“…Firstly, in their analysis of seed-trap data, researches are generally compelled to assume that seeds originate from the closest seed source (i.e. the closest reproductive adult), therefore underestimating actual dispersal [14]–[16]. Secondly, 1D dispersal kernels have the underlying assumptions of isotropic dispersal and habitat homogeneity (across directions and distance), despite general acknowledgement that they rarely hold in reality.…”