Florian Hartig

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Employing plant functional groups to advance seed dispersal ecology and conservation

Clare Aslan, Noelle G Beckman, Haldre S Rogers, Judie Bronstein, Damaris Zurell, Florian Hartig, Katriona Shea, Liba Pejchar, Mike Neubert, John Poulsen, Janneke HilleRisLambers, Maria Miriti, Bette Loiselle, Edu Effiom, Jenny Zambrano, Geno Schupp, Gesine Pufal, Jeremy Johnson, James M Bullock, Jedediah Brodie, Emilio Bruna, Robert Stephen Cantrell, Robin Decker, Evan Fricke, Katie Gurski, Alan Hastings, Oleg Kogan, Onja Razafindratsima, Manette Sandor, Sebastian Schreiber, Rebecca Snell, Christopher Strickland & Ying Zhou

AoB PLANTS, 11(2), plz006 (2019)
Cite this
@article{aslan2019employing,
  author = {Clare Aslan and Noelle G Beckman and Haldre S Rogers and Judie Bronstein and Damaris Zurell and Florian Hartig and Katriona Shea and Liba Pejchar and Mike Neubert and John Poulsen and Janneke HilleRisLambers and Maria Miriti and Bette Loiselle and Edu Effiom and Jenny Zambrano and Geno Schupp and Gesine Pufal and Jeremy Johnson and James M Bullock and Jedediah Brodie and Emilio Bruna and Robert Stephen Cantrell and Robin Decker and Evan Fricke and Katie Gurski and Alan Hastings and Oleg Kogan and Onja Razafindratsima and Manette Sandor and Sebastian Schreiber and Rebecca Snell and Christopher Strickland and Ying Zhou},
  title = {Employing plant functional groups to advance seed dispersal ecology and conservation},
  journal = {AoB PLANTS},
  volume = {11},
  number = {2},
  pages = {plz006},
  year = {2019},
  doi = {10.1093/aobpla/plz006},
}

DOI: 10.1093/aobpla/plz006
Citation statistics: 58 (Google Scholar) · 57 (OpenAlex), as of 29 October 2026

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Funding

This study was supported through funding by US National Science Foundation (DEB-1548194); National Socio-Environmental Synthesis Center under the US National Science Foundation (DBI-1052875); Swiss National Science Foundation (SNF) (PZ00P3_168136/1); German Science Foundation (DFG) (ZU 361/1-1).

View article (DOI)

Abstract

Seed dispersal enables plants to reach hospitable germination sites and escape natural enemies. Understanding when and how much seed dispersal matters to plant fitness is critical for understanding plant population and community dynamics. At the same time, the complexity of factors that determine if a seed will be successfully dispersed and subsequently develop into a reproductive plant is daunting. Quantifying all factors that may influence seed dispersal effectiveness for any potential seed-vector 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. Building on current frameworks, we here posit 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, we 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. 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.

What the paper shows and why it matters

(AI-generated)

Seed dispersal, the movement of seeds away from the parent plant, helps plants reach suitable sites and escape natural enemies. Predicting how global change and the loss of animal dispersers will affect plant populations therefore requires knowing when and how much dispersal matters to a plant’s fitness. The Seed Dispersal Effectiveness (SDE) framework (Schupp et al. 2010) is a reasonable way to organise the many interacting factors involved. Applied in full, however, it needs up to 15 measured quantities for each pair of plant and disperser species, which is out of reach for thousands of species pairs. Earlier functional groupings, for example of seed dispersers (Dennis and Westcott 2006), stayed narrow in scope. Dispersal syndromes, which sort plants by the type of vector (animals or wind) that disperses their seeds, risk being too crude to predict what losing a vector means. The paper questions the use of the individual species as the unit of analysis.

The paper argues that the Seed Dispersal Effectiveness framework should use plant functional groups (groups of species sharing an ecological function) instead of individual species as its units of analysis. The groups are defined by how much it matters to a plant whether its seeds are dispersed (for example, high colonisation ability), where or when they are dispersed (for example, intolerance of shade) and by which vector (for example, seed size). Table 1 lists 17 such groups, almost all paired with a contrasting trait for which losing dispersal should matter less. Published cases illustrate rather than test the vector category: the large-seeded plant Platymitra macrocarpa in Thailand appears to depend on which animals disperse it, whereas for two small-seeded Miconia species in Brazil the dispersing birds differed in the number of seeds moved but not in dispersal quality. To avoid overgeneralising, the paper proposes to test whether predictions derived from the groups hold against data on single species, collected in a standardised way across many systems.

Figure 1. Seed dispersal exemplifies ecological complexity. From Aslan et al. (2019), AoB PLANTS, licensed under CC BY 4.0. Click the image to enlarge.

If groups pass such tests, researchers and conservation planners could judge from a species’ traits whether it is likely to suffer from the loss of its dispersers, and could generalise across species and systems with far less data. The paper offers a proposal and research agenda, not a test, and invites the ecological community to join in.

References

  • Schupp et al. (2010). Seed dispersal effectiveness revisited: a conceptual review. New Phytologist 188, 333–353. doi:10.1111/j.1469-8137.2010.03402.x
  • Dennis & Westcott (2006). Reducing complexity when studying seed dispersal at community scales: a functional classification of vertebrate seed dispersers in tropical forests. Oecologia 149, 620–634. doi:10.1007/s00442-006-0475-3