Defining functional groups relevant to the importance of seed dispersal


Plants rely on seed dispersal vectors — for example, animals, wind and water — to move across the landscape. Through dispersal, plants may experience reduced exposure to competition, predation and parasitism; colonize open habitats after disturbance; reach potential suitable microsites in otherwise unsuitable landscapes; track climate fluctuations and environmental change; and contribute to gene flow within and between populations. Seed dispersal is critical to plant fitness and plant community dynamics. However, measuring and tracking all factors that influence seed dispersal effectiveness for any potential seed-disperser relationship would require an unrealistically large amount of time, materials, and financial resources. On the other hand, being able to make dispersal predictions is critical for predicting whether single species and entire ecosystems will be resilient to global change.

Palm tanager
Palm tanager (Thraupis palmarum) consuming Cecropia sp. seeds in Panama. Image credit: P.J. Bath, aligningvisions.com (used with permission).

In a recent study published in AoBP, Aslan et al. suggest that seed dispersal ecology should adopt plant functional groups as analytical units to reduce this complexity to manageable levels. Functional groups can be used to distinguish, for their constituent species, whether it matters (i) if seeds are dispersed, (ii) into what context they are dispersed and (iii) what vectors disperse them.  To avoid overgeneralization, the authors propose that the utility of these functional groups may be assessed by generating predictions based on the groups and then testing those predictions against species-specific data. We suggest that data collection and analysis can then be guided by robust functional group definitions. To grow our understanding of seed dispersal ecology and to predict the likely effects of environmental changes, we advocate a new focus on seed dispersal functional groups. Generalizing across similar species in this way could help us to better understand the population and community dynamics of plants and tackle the complexity of seed dispersal as well as its disruption. The authors invite the ecological community to join them in this effort.

NOTE: 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”. For related articles please see the special issue here.

Clare Aslan received a PhD in Ecology from the University of California-Davis. Clare is currently the co-Director of the Landscape Conservation Initiative at Northern Arizona University and an Assistant Professor in the School of Earth and Sustainability. She is also a Senior Scientist with Conservation Science Partners.

Clare is a community ecologist and conservation biologist interested primarily in the effect of environmental change on species interactions, particularly mutualism. She studies seed dispersal and pollination as focal systems for understanding how climate change, biological invasions, and fire drives changes in interaction networks and system resilience. She is also interested in socioecological questions, particularly surrounding feedbacks between ecological functions and management decision-making.



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