Rapid changes in seed dispersal traits may modify plant responses to global change

When climatic or environmental conditions change, plant populations must either adapt to these new conditions, or track their niche via seed dispersal. Adaptation of plants to different abiotic environments has mostly been discussed with respect to physiological and demographic parameters that allow local persistence. However, rapid modifications in response to changing environmental conditions can also affect seed dispersal, both via plant traits and via their dispersal agents. Studying such changes empirically is challenging, due to the high variability in dispersal success, resulting from environmental heterogeneity, and substantial phenotypic variability of dispersal- related traits of seeds and their dispersers. The exact mechanisms that drive rapid changes are often not well understood, but the ecological implications of these processes are essential determinants of dispersal success, and deserve more attention from ecologists, especially in the context of adaptation to global change.

Seed dispersal can be modified via rapid changes in plant dispersal traits at different stages and under different environmental change situations. Changes in temperature, precipitation, habitat availability, biotic interactions or nutrient availability can elicit a plastic response that may or may not be heritable, but may allow a plant to rapidly respond to the changing conditions. This is exemplified by the changes in dispersal traits in Carduus nutans under drought conditions studied by Teller et al. (2014). We use this example to explore the roles of genetics and phenotypic plasticity on rapid changes in seed dispersal as a result of global ecological change.

In a recent review published in AoBP, Johnson et al. explore whether rapid changes in seed dispersal traits may modify plant responses to global change. First, they consider evidence for rapid modification of seed dispersal traits, including plant traits, animal disperser traits and changes in external conditions. They discuss the potential mechanisms driving rapid response of dispersal traits, including phenotypic plasticity, epigenetics and rapid evolution. Finally, they propose a path forward to better understand the ways in which seed dispersal may buffer the effects of global ecological change. They conclude that if we combine our empirical understanding of heritable and non-heritable mechanisms of seed dispersal with theoretical and mathematical modelling of dispersal pathways, we are likely to improve predictions and improve our ability to predict further into the future for best- and worst-case scenarios.

This articles was published in the AoBP special issue “The Role of Seed Dispersal in Plant Populations: Perspectives and Advances in a Changing World” (link: https://bit.ly/2KQ6txA)

Researcher highlight

Jeremy Johnson became interested in forest ecology while growing up near the Rocky Mountains in Colorado, USA. After completing his BS in natural resources at Colorado State University he spent several years working for the US National Park Service and the US National Forest Service before completing a PhD in geography focusing on forest landscape genetics at Texas A&M University. Jeremy now holds a joint postdoctoral appointment with Northern Arizona University in the School of Forestry and with the USDA Forest Service where he spends most of his time at the Dorena Genetic Resource Center in Cottage Grove, Oregon surrounded by the big trees of the Pacific Northwest.

Jeremy is a forest ecologist and geneticist with broad research interests geared towards understanding the spatial and temporal patterns of how forests respond to multiple threats associated with global ecological change by specializing in the use of geographic, landscape ecological, and genetic tools and theory. Specifically, Jeremy investigates patterns of plant movement through seed dispersal, patterns of local adaption and natural genetic resistance to invasive forest diseases. Jeremy’s goal is to ensure the long-term survival of forests with effective conservation interventions and management.

Further reading

Johnson, J. S., Cantrell, R. S., Cosner, C., Hartig, F., Hastings, A., Rogers, H. S., … Pufal, G. (2019). Rapid changes in seed dispersal traits may modify plant responses to global change. AoB PLANTS, 11(3). https://doi.org/10.1093/aobpla/plz020