Medium-Sized Seeds Disperse Better Than Large Seeds: Study

Contrary to common belief, a new study shows that medium-sized seeds have the highest dispersal success due to scatter-hoarding rodents.

AsianScientist (Aug. 22, 2016) – Chinese researchers have found that medium-sized seeds have the highest dispersal success through scatter-hoarding rodents. The study has been published in the journal Ecology.

Seed size selection under rodent predation and dispersal is a complex process. However, it is not clear if there is a trade-off during the dispersal process and what implications that would have for plant seed size.

In the study, researchers from Xishuangbanna Tropical Botanical Garden and the Chinese Academy of Sciences investigated the effects of seed size (measured as seed mass) on the seed fates of a dominant plant Pittosporopsis kerrii (Icacinaceae) dispersed by scatter-hoarding rodents in the Xishuangbanna tropical forest, Yunnan, southwest China over a five-year period.

They divided the dispersal process into two stages: as pre-removal (at seed station or under parent tree) and post-removal (removed from seed station or from parent tree). The study was aimed at testing the hypothesis that large-sized seeds would have highest dispersal success because small-sized seeds are more likely predated while large-sized seeds are more likely dispersed.

Interestingly, they found that seeds experienced conflicting pressures at pre-and post-removal stage. Small-sized seeds were more frequently eaten at the early dispersal stage, while large-sized seeds were more likely to be eaten and pilfered (or larder hoarded) at the late dispersal stage, which resulted in highest dispersal success of medium-sized seeds.


The article can be found at: Cao et al. (2016) Differential Foraging Preferences on Seed Size by Rodents Result in Higher Dispersal Success of Medium-sized Seeds.

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Source: Chinese Academy of Sciences.
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