Papers by Kimberly Holbrook
AoB PLANTS, 2019
As the single opportunity for plants to move, seed dispersal has an important impact on plant fit... more As the single opportunity for plants to move, seed dispersal has an important impact on plant fitness, species distributions and patterns of biodiversity. However, models that predict dynamics such as risk of extinction, range shifts and biodiversity loss tend to rely on the mean value of parameters and rarely incorporate realistic dispersal mechanisms. By focusing on the mean population value, variation among individuals or variability caused by complex spatial and temporal dynamics is ignored. This calls for increased efforts to understand individual variation in dispersal and integrate it more explicitly into population and community models involving dispersal. However, the sources, magnitude and outcomes of intraspecific variation in dispersal are poorly characterized, limiting our understanding of the role of dispersal in mediating the dynamics of communities and their response to global change. In this manuscript, we synthesize recent research that examines the sources of indi...
Seed dispersal: theory and its application in a changing world
A study was conducted at the Tiputini Biodiversity Station and Yasuní Research Station in Orellan... more A study was conducted at the Tiputini Biodiversity Station and Yasuní Research Station in Orellana Province, Ecuador from 2001 to 2005 to estimate seed dispersal distances for a neotropical tree, Virola flexuosa, based solely on toucan movements and seed retention times, and to present a spatially explicit model, which more realistically 'outlines' the dispersion patterns generated by toucans. More than 400 h of observations at 13 individual fruiting trees indicate that Ramphastos and Pteroglossus pluricinctus represent 64.3% of visits and remove more than 52.0% of dispersed seeds. Seed retention experiments revealed little difference between Ramphastos and Pteroglossus toucans with the average seed retention time of approximately 30 minutes. A small percentage were retained in the gut for around 100-140 minutes by Ramphastos, suggesting a trend for longer retention times by the larger Ramphastos species. Ramphastos and P. pluricinctus had mean home range of 86 and 191 ha, r...
Molecular Ecology Notes, 2006
Eight highly polymorphic microsatellite loci were developed for Virola flexuosa from a (CA) nenri... more Eight highly polymorphic microsatellite loci were developed for Virola flexuosa from a (CA) nenriched genomic library for population and seed dispersal studies in eastern Ecuador. Loci show a high level of variation with the number of alleles ranging from 13 to 27. Observed and expected heterozygosities were from 0.313 to 0.896 and 0.552 to 0.937, respectively. The high levels of polymorphism and exclusionary power of the developed markers will likely prove very useful in direct measurement of seed dispersal.
Ecology, 2009
To understand how different frugivores impact dispersal, we studied the assemblage that feed on V... more To understand how different frugivores impact dispersal, we studied the assemblage that feed on Virola flexuosa over a two-year period at two sites differing in hunting pressure in Ecuador. We focus on disperser effectiveness and test the hypothesis that seed removal, influenced by differential visits of large-bodied frugivores, will differ between hunted and non-hunted sites. All visiting frugivores were identified, and fruit handling behavior and seed removal rates quantified. Seed traps were placed under fruiting trees to estimate crop size and fruit removal. Seventeen bird and three primate species were recorded foraging in V. flexuosa trees. Toucans and primates were the most important dispersers comprising nearly 85% of visits with six toucan species recorded in 74% of visits. A proportionately larger number of seeds were removed from fruiting trees at a non-hunted site (89.4%) than a hunted site (66.8%). In addition, there were significantly more frugivore visits at the non-hunted than the hunted site. The differences in the frugivore assemblage and the number of seeds dispersed from individual trees between two structurally similar forest sites suggest dispersal limitation resulting from a decline in frugivores.
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Papers by Kimberly Holbrook