DNA Fingerprinting Validates Seed Dispersal Curves from Observational Studies in the Neotropical Legume Parkia

Eckhard W Heymann,Pedro Pablo Pinedo Saboya,Kathrin Lüttmann,Inga M Michalczyk,Ronald Bialozyt,Birgit Ziegenhagen

doi:10.1371/journal.pone.0035480

Eckhard W Heymann, Pedro Pablo Pinedo Saboya + Show 4 more

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https://doi.org/10.1371/journal.pone.0035480

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Abstract

BackgroundDetermining the distances over which seeds are dispersed is a crucial component for examining spatial patterns of seed dispersal and their consequences for plant reproductive success and population structure. However, following the fate of individual seeds after removal from the source tree till deposition at a distant place is generally extremely difficult. Here we provide a comparison of observationally and genetically determined seed dispersal distances and dispersal curves in a Neotropical animal-plant system.Methodology/Principal FindingsIn a field study on the dispersal of seeds of three Parkia (Fabaceae) species by two Neotropical primate species, Saguinus fuscicollis and Saguinus mystax, in Peruvian Amazonia, we observationally determined dispersal distances. These dispersal distances were then validated through DNA fingerprinting, by matching DNA from the maternally derived seed coat to DNA from potential source trees. We found that dispersal distances are strongly right-skewed, and that distributions obtained through observational and genetic methods and fitted distributions do not differ significantly from each other.Conclusions/SignificanceOur study showed that seed dispersal distances can be reliably estimated through observational methods when a strict criterion for inclusion of seeds is observed. Furthermore, dispersal distances produced by the two primate species indicated that these primates fulfil one of the criteria for efficient seed dispersers. Finally, our study demonstrated that DNA extraction methods so far employed for temperate plant species can be successfully used for hard-seeded tropical plants.

Highlights

Seed dispersal, i.e. the process of displacing seeds away from the maternal plant, creates the template for the steps within the so-called ‘‘seed dispersal loop’’ [1] like secondary seed dispersal, seed predation, germination and seedling establishment
Keeping track of the fate of individual seeds represents a major challenge in seed dispersal studies
Studies which calculate seed dispersal distances and fitted seed dispersal curves from observational studies make the assumption that seeds voided with faeces can be assigned to a source tree when the outlined rigid criterion is applied

Summary

Introduction

I.e. the process of displacing seeds away from the maternal plant, creates the template for the steps within the so-called ‘‘seed dispersal loop’’ [1] like secondary seed dispersal, seed predation, germination and seedling establishment. A more direct approach to obtain proper estimates of seed dispersal distances is to monitor the behaviour and movement of frugivores directly and continuously and to calculate dispersal distances . This holds true when the occurrence of seeds in defecations can be matched to feeding bouts by frugivores in a specific plant individual. An unambiguous assignment of these seeds to their origin is possible if the following criterion is fulfilled: between the feeding on fruits of a particular plant species and the defecation of seeds from that species, no other feeding plant of the same species must have been visited. We provide a comparison of observationally and genetically determined seed dispersal distances and dispersal curves in a Neotropical animal-plant system

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Results

Conclusion