An overlooked plant–parakeet mutualism counteracts human overharvesting on an endangered tree

SPEZIALE, KARINA L.; LAMBERTUCCI, SERGIO A.; GLEISER, GABRIELA; TELLA, JOSÉ L.; HIRALDO, FERNANDO; AIZEN, MARCELO A.

Royal Society Open Science

The Royal Society Publishing

Año: 2018 vol. 5

The exponential growth of the human population oftencauses the overexploitation of resources and disruption ofecological interactions. Here, we propose that the antagonisteffect of humans on exploited species might be alleviatedwith the advent of a second predator species. We focusedon the complex interactions between an endangered conifer(Araucaria araucana) and two seed exploiters: the Australparakeet (Enicognathus ferrugineus) and human seed collectors.We tested the importance of partial seed consumption byparakeets as an escape from human seed harvesting. Althoughparakeets frequently ate whole seeds, a substantial proportionof the seeds found under trees were only partially eaten andavoided by human seed collectors. These seeds germinated at asimilar proportion but faster than intact seeds under laboratoryconditions. Our results revealed an overlooked mutualismbetween parakeets and an endangered tree. Incomplete seedeating by parakeets, plus selection against these eaten seeds byhumans, may enhance regeneration possibilities for this coniferspecies subject to human seed collection, turning the scale ofthe antagonism?mutualism continuum to the mutualistic side.In this context, parakeets might be providing an importantservice in those forests subject to human harvesting by allowinga fraction of seeds to escape human predation.