Evaluation of abundance and diversity of arbuscular mycorrhizal spores in Austrocedrus chilensis forests affected by wildfire in Patagonia,Argentina

TALARICO, S. ; SALGADO SALOMÓN, M.E; BARROETAVEÑA, C.; URRETAVIZCAYA,F.; GIANOLINI, S.

Valdivia

Workshop; International workshop of Mycorrhizal symbiosis in the southern cone of south America; 2017

Universidad Austral de Chile

During February of 2015, near to Cholila (Chubut, Argentina) an extreme behaviour wildfire occurred, leaving 27,101 ha burned. Approximately 5700 ha of this area corresponded to pure and mixed Austrocedrus chilensis forests. The symbiosis between arbuscular mycorrhizal (AM) fungi and A. chilensis has been established and has great ecological importance for the species regeneration. Therefore, is important to determine AM spore bank state in post-fire underground in order to understand the evolution of these stands and to properly manage their restoration. This study was carried out in three sites with A. chilensis forest near to Las Horquetas (Cholila, Chubut) where three treatments were selected: unburned forests, forests moderately affected, and forests severely affected by fire, with the aim of determine and compare the abundance and diversity of AM spores in soil affected by different fire severities. Five composite soil samples were taken in each treatment and site, at the first 15 cm of soil profile; AM spores were extracted with the wet sieving-sucrose gradient method, quantified and classified according to morphological characteristics in binocular stereomicroscope. Arbuscular mycorrhizal spores were significantly more abundant in moderate fire treatment (258 spores/100 g dry soils). It was possible to identify 6 different morpho-species present in all treatments, two of them (Glomus-like) being the most abundant. Evenness declined significantly in moderate severity treatment (EI=0.68; EA-V=0.74, p