A demographic approach for plant invasions
Dr. Satu Ramula
Biodiversity Unit, Lund University, Sweden
Invaders generally show better individual performance than non-invaders and therefore, species traits could potentially be used to predict species invasiveness outside their native range. However, comparative studies have usually correlated traits with the invasiveness status of species, while few studies have investigated traits explicitly in relation to population performance in terms of the long-term population growth rate. Using data on multiple populations of an invasive herb in its invaded range, I demonstrate that the measures of a single or a few plant traits do not necessarily reflect population performance and invasiveness correctly because only some fitness-related plant traits map directly into the long-term population growth rate. Therefore, a demographic approach that takes the whole life-cycle into account is required. I illustrate that this demographic approach provides a tool for identification of the demographic processes with the greatest impact on population growth rates, enabling a better understanding of the population dynamics and potential management strategies for invasive plant species.
