Consequences of intraspecific variation in seed dispersal


As the single opportunity for plants to move, seed dispersal has an important impact on plant fitness, species distributions and patterns of biodiversity. However, models that predict extinction risk of species, range shifts, and biodiversity tend to rely on average dispersal distances. Yet we know that seed dispersal is highly variable even within a single species (e.g., some seeds go very far and some barely move away from their parent plant, some seeds end up in great quality habitats and some end up on roads). Individual variation in the seed dispersal process is multifaceted and can include differences in the number of seeds dispersed, the specific traits of the dispersed seeds, the treatment of the seed during transit, the dispersal distance and the quality of the habitat in which they are deposited. By focusing on the mean population value, variation among individuals or variability caused by complex spatial and temporal dynamics is ignored.

Intraspecific variation in dispersal and non-linear averaging. Seed dispersal distances from parent trees for three species of toucans (Ramphastidae) in the New World tropics. Image credit: Snell et al.

In a recent Editor’s Choice Point of View article published in AoBP, Snell & Beckman et al. look to understand the consequences of intraspecific variation in seed dispersal for plants and emphasize its implications for plant fitness, populations and communities. The authors first consider the factors influencing seed dispersal, including fruit and seed size, fecundity, plant height and dispersal specific factors. They consider the consequences of variation in these factors on local population dynamics, the spatial spread of populations, local community dynamics and evolution, then discuss the relevance of these in the context of anthropogenic and global climate change. Finally, the authors provide some recommendations for best practices moving forward and suggest some new approaches for studying individual variation and its implications. Specifically, they suggest (i) measuring and reporting variability in seed dispersal to quantify variance, (ii) incorporating variability in dispersal into models to simulate its effect and (iii) use the results of these models to design experiments to test the predictions about the role of intraspecific variability in seed dispersal.

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

Dr Rebecca Snell (right) and Dr Noelle Beckman (left)

Dr. Rebecca Snell grew up in Canada, and earned her Ph.D. in forest ecology from the University of Toronto. She then spent several years in Switzerland, as a post-doctoral research fellow in the Forest Ecology professorship with Prof. Dr. Harald Bugmann, at the Swiss Federal Institute of Technology Zurich (ETH Zurich). She is currently an Assistant Professor in the Department of Environmental and Plant Biology, at Ohio University.

Rebecca and her research group are primarily interested in understanding how forests will respond to climate change and disturbances. We use a variety of methods, such as field work, statistical modelling and process-based models (i.e., dynamic vegetation models, DVMs). The empirical work is used to parametrize processes that are currently poorly represented in DVMs. Rebecca and her lab is particularly interested in the early plant life stages, such as reproduction, seed dispersal and germination – and developing better models to simulate how climate change will impact each of these processes.

 

Dr. Noelle Beckman earned her Ph.D. in Ecology, Evolution, & Behaviour at the University of Minnesota, Twin Cities and her B.S. in Biology at Washington and Lee University. She was a Postdoctoral Fellow at the Mathematical Biosciences Institute (MBI) and the National Socio-Environmental Synthesis Center (SESYNC). She currently is an Assistant Professor in the Biology Department and Ecology Center at Utah State University.

Noelle and her research group investigate interactions between plants and their environment occurring over multiple scales and examine the role of these interactions in limiting plant populations and maintaining biodiversity. Many of these interactions are disrupted by global change, and they examine the consequences of these disruptions for plant communities and ecosystem functions. They use a combination of empirical and quantitative approaches to address their research questions. The group’s aim is to conduct transdisciplinary and actionable research that contributes to solutions of socio-environmental problems, disseminate results to a broad community, and promote a diverse and inclusive community that welcomes and respects diverse backgrounds and perspectives.



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