Resumen

LOVERA, Milagros  y  CUENCA, Gisela. Diversity of arbuscular mycorrhizal fungi (amf) and mycorrhizal potential of the soil from a natural and a disturbed savannah from la gran sabana, venezuela. INCI [online]. 2007, vol.32, n.2, pp.108-114. ISSN 0378-1844.

The benefits provided by arbuscular mycorrhizas (AM) to plants are well known, especially those related to the improvement of mineral nutrition and protection against root pathogens, among others. Although 80% of vascular plants are able to form AM, it is considered that the association lacks specificity from a taxonomical point of view. However, recent evidence has arisen about the influence of the diversity of AM fungi (AMF) on the productivity, diversity, competitive relationships and functioning of natural ecosystems. In addition, there are evidences that support the idea that AMF diversity is severely affected by disturbance and that some AMF are particularly sensitive to human activities. The aim of this work is to compare the diversity of AMF and the mycorrhizal soil potential of an undisturbed savannah from La Gran Sabana, Bolivar state, Venezuela, with an adjacent disturbed savannah. An exhaustive inventory of AMF spores was done taking samples along the year, across the soil profile and using trap culture. Results show that there is a high AMF diversity in the natural savannah studied and many of the collected spores correspond to new species. Results also pointed out that spores belonging to Scutellospora and Gigaspora are highly vulnerable to disturbance. This change in AMF species composition might be related with the slow recovery and the type of plant community that finally will establish in these much degraded areas.

Palabras clave : Diversidad; Esporas; Micorrizas Arbusculares; Potencial Micorrízico; Sabanas Degradadas.