Mycorrhizal status and responsiveness of early successional communities from chaquean region in Central Argentina

Abstract

Theoretical models suggest that early successional communities would be dominated by non-mycotrophic plant species and thus, mycorrhizas do not have an important role in structuring these plant communities. Here we test these models gathering data from Chaquean region from central Argentina. The evidence shows that most of the studied ruderal species in these communities harbour arbucular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in their roots. In addition, experimental data shows that AMF have antagonistic effects on three abundant ruderal fast-growing pioneer species (growing alone and interacting with each other) and promote eveness in this simplified plant community. The effects of AMF on ruderal pioneers observed here, mirror those attributed to herbivores and pathogens, suggesting a previous unrecognised mechanism by which AMF might promote secondary succession. Altogether, the evidence suggests that AMF and DSE should be included in models that predict the effects of fungal root symbionts in early secondary succession communities.