Frugivory at Juniperus communis depends more on population characteristics than on individual attributes
D. García, Grupo de Ecología Terrestre, Departamento de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, Granada 18071, Spain (fax 34 958243238; firstname.lastname@example.org).
- 1 We investigated the spatio-temporal variation in the interactions between the juniper Juniperus communis and its vertebrate frugivores (avian dispersers of Turdus spp. and predatory rodents Apodemus sylvaticus) in the Mediterranean mountains of south-east Spain.
- 2 Frugivore activity was evaluated at six sites and for 3 years, in relation to both plant reproductive traits (plant size, cone crop and cone size) and characteristics of the immediate environment (distance to the nearest female, abundance of perches, fruiting environment and habitat).
- 3 Plant characteristics and levels of frugivory varied strongly among the six populations. Cone production, cone size and frugivory also differed significantly among years for the same population. Avian frugivory was only occasionally affected by density of cones per plant, abundance of perches or abundance of other fruiting species, or by habitat. Rodent predation was positively related only to the density of cones per plant and then only in two sites.
- 4 Levels of both avian frugivory and rodent predation significantly increased in populations with higher cone production.
- 5 Both groups of vertebrate frugivores responded to the spatio-temporal variation in cone abundance at a regional scale, discriminating more between juniper populations than between individual plants within a population. The outcome of interactions with frugivores at the individual plant level thus proved more dependent on the whole-population characteristics than on individual attributes.