a1 Ecology Department, Autónoma University of Madrid, Cantoblanco 28049 Madrid, Spain
Morphological traits of diaspores that can predict their potential attachment to animal coats may help to model epizoochory in plant populations and communities. The present study tested the role of seed mass, shape and the presence of dispersal structures in the attachment potential of a sample of 14 abundant species in Mediterranean grassland and shrubland, using sheep and cattle coats that were shaken mechanically using a standardized protocol. We also tested recently proposed predictive models for the attachment potential of diaspores. Attachment potential measured on cattle hide was low in comparison with sheep wool for all types of diaspores. Differences between vertically and horizontally positioned coats were significant only for cattle, in which attachment potential was higher in vertically positioned coats. Seed weight was highly significant to predict attachment potential in sheep coats, but yielded significant results only in the case of vertically positioned cattle coats. In both cases, light seeds were best retained. Shape yielded marginally significant results only in the case of horizontally positioned cattle coats. In this case, elongated seeds seemed to be best retained. The presence of appendages in diaspores was significant only for sheep, in which attachment potential was higher for seeds with appendages. Recently proposed predictive models for the attachment potential were found to be highly robust for predicting this parameter in sheep coats, and thus support their generalization for this type of coat.
(Received August 30 2006)
(Accepted January 11 2007)