Seed dispersal shapes ecological and evolutionary dynamics of plant populations. Here, we extend classical diversity measures to study the impact of disperser behavior on seed dispersal. We begin by extending our previous diversity structure approach, which partitioned seed source diversity within and among dispersal sites, into the more general framework of traditional diversity measures. This statistical approach allows an assessment of the extent to which foraging behavior shapes α and γ diversity, as well as the divergence in seed sources among dispersal sites, which we call δ. We also introduce tests to facilitate comparisons of diversity among dispersal sites and seed vectors and to compare overall diversity among sampled systems. We then apply these tools to investigate the diversity blend of parentage resulting from seed dispersal by two avian seed vectors with very different social and foraging behaviors: (1) acorn woodpeckers, transporting Quercus agrifolia acorns, and (2) long-wattled umbrellabirds, transporting Oenocarpus bataua palm nuts. Using these diversity and divergence measures, we test the hypothesis that different foraging behaviors generate distinctive diversity partitions for the two focal tree species. This approach provides a new tool for assessment of the impact of dispersal agents on the seed source structure of plant populations, which can be extended to include the impact of virtually any propagule vector for a range of systems.

Scofield-et-al_AmNat_52938_Quercus-agrifolia_adult-genotypesGenotypes of adult Quercus agrifolia trees found in the study area of Sedgwick Reserve, Santa Barbara County, California. Data are in GenAlEx format, and represent diploid microsatellite genotypes at 10 loci. Loci are named following Scofield et al. 2010 J. Ecology.Scofield-et-al_AmNat_52938_Quercus-agrifolia_pericarp-genotypesGenotypes of Quercus agrifolia collected from Acorn Woodpecker granaries at Sedgwick Reserve, Santa Barbara County, California, in 2006. Data are in GenAlEx format and represent diploid microsatellite genotypes. Genotypes are grouped by granary as indicated by the second column. Locus names follow Scofield et al. 2010 J. Ecology.Oenocarpus bataua microsat dataMicrosatellite fragment lengths at 7 loci for the tropical palm species Oenocarpus bataua. Dataset includes seed (pericarp) tissue from seedlings collected in NW Ecuador2008_Genotype_Oenocarpus_data.xls