Seed dispersal by ungulates as an ecological filter: a trait‐based meta‐analysis

Abstract

Plant communities are often dispersal-limited and zoochory can be an efficient mechanism for plants to colonize new patches of potentially suitable habitat. We predicted that seed dispersal by ungulates acts as an ecological filter -which differentially affects individuals according to their characteristics and shapes species assemblages -and that the filter varies according to the dispersal mechanism (endozoochory, fur-epizoochory and hoof-epizoochory). We conducted two-step individual participant data meta-analyses of 52 studies on plant dispersal by ungulates in fragmented landscapes, comparing eight plant traits and two habitat indicators between dispersed and non-dispersed plants. We found that ungulates dispersed at least 44% of the available plant species. Moreover, some plant traits and habitat indicators increased the likelihood for plant of being dispersed. Persistent or nitrophilous plant species from open habitats or bearing dry or elongated diaspores were more likely to be dispersed by ungulates, whatever the dispersal mechanism. In addition, endozoochory was more likely for diaspores bearing elongated appendages whereas epizoochory was more likely for diaspores released relatively high in vegetation. Hoof-epizoochory was more likely for light diaspores without hooked appendages. Furepizoochory was more likely for diaspores with appendages, particularly elongated or hooked ones. We thus observed a gradient of filtering effect among the three dispersal mechanisms. Endozoochory had an effect of rather weak intensity (impacting six plant characteristics with variations between ungulate-dispersed and non-dispersed plant species mostly below 25%), whereas hoof-epizoochory had a stronger effect (eight characteristics included five ones with above 75% variation), and fur-epizoochory an even stronger one (nine characteristics included six ones with above 75% variation). Our results demonstrate that seed dispersal by ungulates is an ecological filter whose intensity varies according to the dispersal mechanism considered. Ungulates can thus play a key role in plant community dynamics and have implications for plant spatial distribution patterns at multiple scales.Plant communities are often dispersal-limited and zoochory can be an efficient mechanism for plants to colonize new patches of potentially suitable habitat. Our analysis is the first synthesis of ungulate seed dispersal that compares characteristics from both non-dispersed and dispersed diaspores, distinguishing the three zoochory mechanisms ungulates are involved in: endozoochory, hoof-epizoochory and fur-epizoochory. We confirmed that seed dispersal by ungulates is an ecological filter whose intensity increases from endozoochory, then hoof-epizoochory to finally fur-epizoochory. By filtering seed traits through dispersal, ungulates can thus play a key role in plant community dynamics and have implications for plant spatial distribution patterns at multiple scales. Synthesis

High potential of sub-Mediterranean dry grasslands for sheep epizoochory

“…Our findings are consistent with the results from the above mentioned studies, confirming that diaspores with appendages (e.g. hooks, awns, spines, bristles, hairs and wings) are more likely to be dispersed in the fur [1,27,44]. However, the lack of these diaspore structures (e.g.…”

“…Vremščica recorded in previous studies [30,42], were also found in the fur. In many studies the ability of diaspores to move with sheep transhumance has been observed [1,10,13,20,27]. However, no single study has sampled the high number of species demonstrated in the present work.…”

“…Various strategies of fur-epizoochoric dispersal according to diaspore morphology have already been proposed [1,27]. Both seed mass and seed morphology were positively correlated (on 130 species tested) with attachment potential in a model [25].…”

“…Different diaspore traits are characteristic for fur-epizoochory and hoof-epizoochory [27]. Diaspores (mainly seeds) with appendages, particularly elongated or hooked ones, are more likely dispersed via fur-epizoochory, whereas light and round diaspore without hooked appendages are associated with hoof-epizoochory [27].…”

The Anthelmintic Ingredient Moxidectin Negatively Affects Seed Germination of Three Temperate Grassland Species

“…Besides techniques such as the transfer of seed-containing plant material or seeding (reviewed in [47]), the guidance of mobile livestock herds is suggested as a restoration measure improving an exchange of seeds over short and long distances [48]. The protection of the high capacity of domestic ungulate species in transferring seeds, particularly via faeces [49], becomes increasingly important with respect to ongoing land use and climate changes.…”