Gorchov, David , Noe, Douglas .
Assessing the relative importance of long-distance dispersal vs. diffusion in the invasion of an exotic shrub, Lonicera maackii, with a Bayesian model.
As part of a larger investigation to understand the relative importance of long-distance dispersal vs. diffusion in the invasion of non-native plants, we are using age structure to infer the contribution of external propagule pressure vs. within-population reproduction to recruitment. We are studying the age structures of Amur honeysuckle, Lonicera maackii (Rupr.) Herder (Caprifoliaceae), a shrub native to northeast Asia that is a major forest invader in eastern North America. Our study area is a set of recently invaded woodlots in an agriculture landscape matrix in Darke County, Ohio. We sampled the 30 largest L. maackii individuals in each of 12 populations (woodlots) and aged these by counting annual rings in stem cross-sections. We have constructed a Bayesian hierarchical probability model to describe recruitment as a result of two independent processes: external recruitment (long-distance dispersal) and internal recruitment (reproduction of shrubs within the population). External recruitment is modeled as one Poisson process, and internal recruitment is modeled as a combination of Poisson processes, each governed by the age-based reproductive rates of existing shrubs in the population. Individuals in the oldest four 1-year age classes are assumed to be from external recruitment, given minimum age at which shrubs reproduce. We used the age structures of the 12 populations to fit our probability model. We then used this model to estimate the relative contribution of external and internal recruitment over the next two four-year intervals for each population. These findings will be compared to those from microsatellite markers derived from many of the same individuals in the same populations. Understanding the relative importance of long-distance dispersal vs. diffusion will inform management, e.g. whether it is more effective to patrol for isolated shrubs in otherwise uninvaded areas or kill mature shrubs at the advancing edge of an invasion.
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1 - Miami University, Department Of Botany, 316 Pearson Hall, Oxford, OH, 45056, USA
2 - Miami University, Statistics, Oxford, OH, 45056, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 9th, 2012
Time: 10:30 AM