Dispersal is a critical life history stage for plants determining the persistence of populations and the distribution of species. Despite the importance of seed dispersal, we have much still to learn about the factors that determine how far species’ seeds travel. Indeed, for the vast majority of species we have no information on how or how far they disperse. The increase in publications on species dispersal abilities in the last 25 years has allowed the development of global scale data sets on species dispersal traits. These types of data sets have become an exciting tool, allowing us to test both long-standing ecological theory and answer some of the most basic questions in dispersal ecology.
Here I show how large-scale dispersal trait databases (consisting of 100’s of species) have been used to test the dispersal investment-distance hypothesis and for a trade-off between maternal provisioning and dispersal distance. I also show how global scale studies have helped to develop our understanding of large-scale landscape patterns in dispersal and how to predict species dispersal abilities from simple plant traits.
Results/Conclusions
Results from these large scale studies have both confirmed and overturned ecological theory. For example, the long-held belief that small-seeded species disperse further than large-seeded species is incorrect. A trade-off between species dispersal abilities and seed mass (maternal provisioning) is only present once you account for plant height. The first global confirmation of the dispersal investment-distance hypothesis has also been provided through a global scale analysis. Species with high investment in dispersal structures on their seeds, disperse their seeds greater distances than those species with no or low investment in dispersal structures. Exploration of simple plant traits as predictors of dispersal distance has found seed mass is not the best proxy for species dispersal distances, but rather dispersal investment or plant height should be used instead.
Global-scale, cross-species analyses have provided a critical role in progressing our understanding of dispersal. They can help answer some of our most basic questions on dispersal, disprove or develop new and exciting theories and improve our ability to predict species’ movements across landscapes.