Presencia de hongos micorrízicos arbusculares en tres zonas de bosque seco tropical

Abstract

The Tropical Dry Forests (TDF) in Tolima, Colombia, face threats from agricultural expansion and deforestation, despite their importance for biodiversity and ecosystem services (Banda et al., 2016; Rangel-Churio & Betancur, 2008). This study focused on exploring arbuscular mycorrhizal fungi (AMF) in the TDF, seeking to understand their relationship with environmental conditions. Soil samples were analyzed in three municipalities (Melgar, Prado, Purificación), counting 3354 AMF spores without finding statistically significant differences (F(2,6)= 3.658 and p= ,91). Although soil pH varied, it showed no significant differences between municipalities (ANOVA: F(F(2,6=4.836, p=0.56). A significant negative correlation was found: lower pH correlated with higher AMF spore concentration (Pearson: r=-0.786, p=0.013. Thirty-seven forest species belonging to 25 botanical families were identified, with Fabaceae being the most prominent family (12.77%), and Vochysia lehmannii being the species with the highest number of individuals (5). Although no statistically significant differences were found, the variation in results is attributed to soil characteristics, particularly pH, affected by soil-forming factors (USDA, 2014). Samples from Melgar and Prado, in hilly landscapes, exhibited shallow soils with low fertility and low levels of organic matter, which could explain the higher abundance of AMF spores and low pH values. On the other hand, samples from Purificación, located in a piedmont landscape with alluvial soils, showed lower levels of AMF and higher pH. The strong negative correlation between AMF spore abundance and soil pH in the three TDF zones suggests that lower pH corresponds to higher spore abundance, contradicting previous findings (Lenoir et al., 2016; Branco et al., 2022; Hung & Trappe, 1983; Rousk et al., 2009; Bazzicalupo et al., 2021). The impact of agricultural and livestock management in Purificación and Prado was also considered, where productive systems near riparian forest remnants may negatively affect mycorrhizal association and AMF composition, especially under the use of industrial agrochemicals (Jaizme, M. 2009; Hage, K. et al, 2018; Karpouzas, et al, 2022). This study confirms the presence of AMF in the TDF of Tolima, with variations in concentration related to soil pH. Additionally, it highlights the diversity of forest species associated with the dominant relief and landscape.