Drivers of intraspecific variation in seed dispersal are diverse and pervasive

Intraspecific variation in the quantity and quality of seed dispersal has important ecological and evolutionary consequences, yet it is generally ignored in favour of focussing on population mean values. As a result, there are large gaps in our understanding of intraspecific variation in seed dispersal traits. We do not know how pervasive detectable variation in seed dispersal is, what the drivers of individual variation are and to what extent these drivers have independent versus interactive effects. To date there only have been scattered efforts to summarize the breadth of our understanding of the drivers of intraspecific variation in seed dispersal.

Crataegus monogyna
Crataegus monogyna Jacq., oneseed hawthorn, in the Sierra de Cazorla, southern Spain. A number of studies in both Europe, its native range, and in North America, part of its introduced range, have used this species to investigate fruit traits influencing intraspecific variation in seed dispersal. Image credit: E.W. Schupp.

In a newly published Editor’s Choice review published in AoBP, Schupp et al. address these gaps in knowledge and show that drivers of intraspecific variation in seed dispersal are diverse and pervasive. The review highlights that these drivers (such as crop size, fruit size, plant height etc.) are both intrinsic (i.e. variation in traits of individual plants) and extrinsic (i.e. variation in ecological context) in nature. Further, they appear to interact frequently in complex ways. The authors state that current theory does not include or account for these complex and interacting drivers. They conclude the review by providing some outstanding questions on this important topic that may act as a starting point to advancing our understanding of individual variation in seed dispersal. 

This review 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.