Seed dispersal by animals: exact identification of source trees with endocarp DNA microsatellites

A long-standing challenge in studies of seed dispersal by animal frugivores has been the characterization of the spatial relationships between dispersed seeds and the maternal plants, i.e. the seed shadow. The difficulties to track unambiguously the origin of frugivore- dispersed seeds in natural co...

Descripción completa

Detalles Bibliográficos
Autores: Godoy, José A., Jordano, Pedro
Tipo de recurso: artículo
Fecha de publicación:2001
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/42605
Acceso en línea:http://hdl.handle.net/10261/42605
Access Level:acceso abierto
Palabra clave:avian frugivores
microsatellites
Seed dispersal
seed endocarp
seed shadow
spatial variation
Descripción
Sumario:A long-standing challenge in studies of seed dispersal by animal frugivores has been the characterization of the spatial relationships between dispersed seeds and the maternal plants, i.e. the seed shadow. The difficulties to track unambiguously the origin of frugivore- dispersed seeds in natural communities has been considered an unavoidable limitation of the research field and precluded a robust analysis of the direct consequences of zoochory. Here we report that the multilocus genotype at simple sequence repeat (SSR; microsatellite) loci of the woody endocarp, a tissue of maternal origin, provides an unequivocal genetic fingerprint of the source tree. By comparing the endocarp genotype against the complete set of genotypes of reproductive trees in the population, we could unambiguously identify the source tree for 82.1% of the seeds collected in seed traps and hypothesize that the remaining 17.9% of sampled seeds come from other populations. Identification of the source tree for Prunus mahaleb seeds dispersed by frugivores revealed a marked hetero- geneity in the genetic composition of the seed rain in different microhabitats, with a range of 1– 5 distinct maternal trees contributing seeds to a particular landscape patch. Within- population dispersal distances ranged between 0 and 316 m, with up to 62% of the seeds delivered within 15 m of the source trees. Long distance dispersal events, detected by the exclusion of all reproductive trees in the population, accounted for up to 17.9% of the seeds sampled. Our results indicate strong distance limitation of seed delivery combined with infrequent long-distance dispersal events, extreme heterogeneity in the landscape pattern of genetic makeup, and a marked mosaic of multiple parentage for the seeds delivered to a particular patch