INVESTIGADORES
DIMARCO Romina Daniela
congresos y reuniones científicas
Título:
Non-native mammals disperse non-native fungi that promote invasion of non-native trees
Autor/es:
NUÑEZ MARTIN A.; HAYWARD JEREMY; HORTON THOMAS R.; AMICO GUILLERMO C.; DIMARCO ROMINA D.; BARRIOS-GARCIA M. NOELIA; SIMBERLOFF DANIEL
Reunión:
Conferencia; 97th ESA Annual Meeting; 2012
Resumen:
Background/Question/Methods
Biological invasions are complex phenomena since many factors determine their outcome. One key
aspect is the interaction of the non-natives with the local biota. Interaction with local species may be
especially important for exotic species that require an obligatory mutualism, such as the case of
members of the Pinaceae family that need ectomycorrhizal (EM) fungi. EM fungi and seed of Pinaceae
disperse independently, so different vectors can be involved in their dispersal. Mammals such as deer,
wild boar, and rodents can disperse EM fungi. We studied the role of mammals as dispersal agents of EM
fungi on Isla Victoria, Argentina. On this island ca. 80 years ago 135 species of exotic trees, many of
them Pinaceae, were introduced. Only a few of these species have become invasive, and they are found
in high densities only near plantations, partly because Pinaceae trees cannot find EM fungi when their
seeds land far from plantations. With greenhouse experiments using animal feces as inoculum, plus
observational and molecular studies, we examined how local mammals disperse EM fungi. This project
aimed to determine which animals can act as vectors of the mycorrhizal fungi.
Results/Conclusions
We found that wild boar and deer, both non-native, are dispersing EM fungi. Approximately 30% of the
seedlings growing with feces of wild boar and 15% of the seedling growing with deer feces were
colonized by EM fungi. Seedlings growing in control pots were not colonized by EM fungi. We attempted
to collect feces of rodents, but observational evidence confirms that rodents are very rare near and in
the plantations of non-native trees, so their ecological role seems to be negligible in the zones studied.
We found low diversity of fungi colonizing the seedlings, possibly owing to animal preferences and/or the
differential ability EM species to germinate after being ingested. The hypogeous genus Rhizopogon was
the most abundant genus found. Wild boar, a recent addition to the local fauna, seem to be the main
agent dispersing the fungi, so they may be playing a key role in facilitating the invasion of pine trees
and may contribute to triggering their spread. These results show that interactions among non-natives,
in this case from three different kingdoms, seem to explain pine invasions at our study area.