Arbuscular mycorrhizal fungal composition in high montane forests with different disturbance histories in central Argentina

Abstract

The aim of this work was to describe and compare the arbuscular mycorrhizal fungal (AMF) morphospecies community and root colonization in three Polylepis australis forest disturbance types (degraded forest, young forest and mature forest). Rhizosphere soil samples were collected during wet and dry seasons in three sites located at the high mountains of central Argentina. A highly diverse AMF community was detected with 32 different morphospecies. AMF richness, density, Shannon diversity and evenness were neither influenced by forest disturbance type nor by season. Nevertheless, indicator species analyses showed two AMF taxa mostly associated with the degraded forest, one with the young forest and two linked preferentially to the mature forest. Moreover, the latter forest type showed the highest biovolume of Gigaspora spp., a genus representative of conserved ecosystems. P. australis root colonization was similar among forest disturbance types and seasons. However, higher abundance of vesicles was observed during the dry than during the wet season. This study showed that AMF community composition was relatively similar among forests with distinct structural complexity. These results suggest that the AMF community may be resistant to the kind of disturbances that shaped the forests compared, or that natural successional processes may permit AMF to recover from these disturbances.