[POS] Ecology and Enviromment

[POS-45] How are invasive species different? Ecological characteristics of plants revealed by interstage flows and reproductive-value flows.

*Hiroyuki Yokomizo¹, John G Lambrinos², Keiichi Fukaya¹, Takenori Takada³ (1. National Institute for Environmental Studies (Japan), 2. Oregon State University (United States of America), 3. Hokkaido University (Japan))

Keywords:

Matrix population model,Invasive species,Native species,Population growth rate,Reproductive value,Stable stage distribution

From field surveys, demographic data such as survival rates and fecundity can be obtained, enabling the construction of population projection matrices. These matrices can then be used to calculate various demographic statistics—including reproductive value, population growth rate, and elasticity—which provide valuable insights into the ecological characteristics of species. In this study, we introduced two metrics, the interstage flow and the reproductive-value flow, to compare native and non-native plant species. The interstage flow is defined as the product of the a_ij element of the population projection matrix—which represents the transition from stage j to stage i, and the stable stage distribution. The reproductive-value flow is defined as the product of the reproductive value of stage i and the a_ij element of the matrix. In this formulation, stable stage distributions and reproductive values are normalized such that their sums across all life stages equal one, and the total flow across all transitions equals the population growth rate. We obtained population projection matrices for 286 plant species from the COMPADRE Plant Matrix Database. For each species, we determined whether the data were collected within its native range, allowing us to classify species as either native or non-native. We then applied Dirichlet regression to examine how interstage and reproductive-value flows were related to nativeness, life history strategy (semelparous herb, iteroparous herb, shrub, or tree), population growth rate, and matrix dimension. The analysis revealed significant differences in interstage and reproductive-value flows between native and non-native species and suggested that these differences vary depending on life history strategy.