Computational Models

Individual variation in plant dispersal and fecundity increases rates of spatial spread

The highest increases in spread rates occur when variation in dispersal positively co-varies with fecundity.

Mathematical models have long been used to provide insights into the ecology and evolution of the spatial distribution of populations. Outputs from these models have helped to inform conservation and management decisions to control the spread of invasive species and to predict the impacts of climate change on plant populations. Dispersal and fecundity are two fundamental traits underlying the spread of populations. Most spatial distribution models in the past have relied on mean estimates of dispersal and demography, yet these rates often exhibit substantial variation within populations. This individual variation is known to have important consequences on many ecological and evolutionary processes, so it begs the question, what effect do they have on the spatial spread of populations?

Using analytic approximations and numerical calculations based on Acer rubrum, Schreiber & Beckman found that individual variation in mean dispersal rates (σL/L) increase rates of spatial spread. Covariation with individual variation in fecundity (σL/L) and heritability of this variation leads to even higher spread rates. Image credit: M. Pintar

In their new study published in AoBP, Scheiber and Beckman use mathematical models to examine how individual variation in distribution traits and their heritability influence rates of spatial spread of populations. They show that individual variation in dispersal increases spread rates and the more heritable this variation, the greater the increase. The highest increases in spread rates occurs when variation in dispersal positively covaries with fecundity. The results of this study highlight the importance of estimating individual variation in dispersal rates, dispersal syndromes in which fecundity and dispersal co-vary positively, and heritability of these traits to predict the spread of populations.

This article was published as part of the AoBP Special Issue entitled The Role of Seed Dispersal in Plant Populations: Perspectives and Advances in a Changing World.