Under pressure: overgrazing decreases mycorrhizal colonization of both preferred and unpreferred grasses in the Patagonian steppe.

CAVAGNARO, R.A.; PERO, E.; DUDINSZKY N.; GOLLUSCIO R.A; GRIMOLDI A.A.

FUNGAL ECOLOGY

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2019 vol. 40 p. 92 - 97

1754-5048

Arbuscular mycorrhizal fungi (AMF) are related to plant community dynamics and ecosystem functioning.Overgrazing can negatively affect plant performance, and consequently unbalance the associationwith AMF. We studied the grazing effect on AMF colonization for preferred (Bromus pictus and Poaligularis) and unpreferred grasses (Pappostipa speciosa and Pappostipa humilis) by sheep in the Patagoniansteppe. For each species, AMF colonization in ungrazed, moderate and intense grazing sites was quantified.In ungrazed areas, B. pictus showed the highest extent of AMF colonization. Mycorrhizal colonizationwas higher during the active season, and largely reduced by intense grazing conditions. Thedecrease of AMF colonization was maximal for the most preferred species, but also significant for theunpreferred species. Our results suggest that overgrazing could reduce mycorrhizal benefits for the plantby reduction of AMF colonization, which can be a good indicator of ecosystem functioning, eventuallyrevealing an increasing degree of environmental degradation.