PS 12-134 - The influence of time since introduction on the population growth of introduced species and consequences for management

Monday, August 7, 2017
Exhibit Hall, Oregon Convention Center
Hiroyuki Yokomizo, Center for Environmental Risk Research, National Institute for Environmental Studies, Tsukuba, Japan, Takenori Takada, Hokkaido University, Sapporo, Japan, Keiichi Fukaya, Hokkaido University, Japan and John G. Lambrinos, Oregon State University, Corvallis, OR

Optimal management of invasive species requires understanding the key demographic processes governing invasive population dynamics. However, several ecological and evolutionary processes likely act to change the demography of introduced populations over time, and these changes could shift the optimal approach to management as invasions progress. But we have a poor understanding of the degree to which the demographic processes of introduced populations actually do change over time. In this study we used published matrix population models of introduced plant populations to test whether population growth rate changes with time since introduction. We also test whether the proportional influence on population growth of stasis, fecundity, and growth related matrix elements (elasticity) shift with time since introduction.


We did not find a significant effect of time since introduction on population growth rate. However, elasticity to stasis increased while elasticity to growth decreased with time since introduction. Broadly, as time since introduction progressed the elasticities of the introduced plant populations became more similar to those that have been reported for native species. These results suggest that optimal management strategies can shift as the relative importance of demographic transitions change over time. This is especially true when the time scope of management is long or the available demographic data were obtained in the past.