INVESTIGADORES
MENOYO Eugenia
artículos
Título:
Arbuscular mycorrhizas and performance of Polylepis australis trees in relation to livestock density
Autor/es:
MENOYO E; RENISON D; BECERRA A
Revista:
FOREST ECOLOGY AND MANAGEMENT
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2009 p. 2676 - 2682
ISSN:
0378-1127
Resumen:
Polylepis australis trees endemic to Argentina dominate the canopy of subtropical high altitude forests.
Here, livestock rearing is themain economic activity and is suspect of the low performance of P. australis
trees through direct and indirect effects which could include the reduction in arbuscular mycorrhizal
fungi (AMF) and their benefit to trees. To elucidate the role of AMF, we compare plant performance
indicators, arbuscular mycorrhizal (AM) colonization and AMF communities in 20 trees distributed in
two areas of central Argentina which differed in livestock grazing intensity. The area with high livestock
density presented more soil degradation and trees with a lower overall plant performance than the area
with reduced livestock density. The AM colonization values of P. australis were considerably higher than
reported for other tree species and the area with high livestock density had a lower proportion of
arbuscules and higher proportion of hyphae, while vesicles and AM colonization all structure
considered together did not differ between areas. Overall AMF spore number and ofmost species when
considered separately was significantly higher in the area with high livestock density, suggesting a high
tolerance and adaptation of AMF to livestock. We conclude that a reduction in livestock improves the
performance of P. australis, that this improvement could bemediated by an increase in the proportion of
arbuscules, but there does not appear to be any limitation in AM colonization or AMF spore number
which could otherwise be limiting forest restoration.