Browsing by Author "Toy-Opazo, Octavio"

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    Control of invasive conifers in temperate Andean forests promotes native vegetation restoration, but requires continuous management
    (2024) Fuentes-Ramirez, Andres; Vargas-Gaete, Rodrigo; Toy-Opazo, Octavio; Munoz-Gomez, Nayadeth; Salas-Eljatib, Christian; Pauchard, Anibal
    Non -native conifers have been planted widely because of their growth potential and wood quality. However, many of them have become invasive in the introduced ranges. In Chile, the initial introduction of non -native conifers helped the recovery of degraded land, but today some pine species present a high invasion risk when they are not properly managed, leading to detrimental impacts on natural ecosystems and biodiversity. Such is the case of Douglas fir ( Pseudotsuga menziesii ), a species listed as invasive in south -central Chile, as well as in many other countries, when it establishes beyond the original plantation range. The main goal of this research was to characterize the invasion pattern of P. menziesii within a recently-declared protected area nearby the Conguill & iacute;o National Park in the Andes Cordillera. We aimed at determining the key factors that promote the invasion of P. menziesii outside the original plantations. We established five 1,000 m 2 sampling transects (i.e., 100 x10 m), considering two invasion conditions: (i) within the native forest and (ii) far into open scrub areas, both adjacent to P. menziesii plantations. We measured forest structure, soil nutrients, the floristic composition and pine regeneration before and after controlling the invasion within each study conditions. We found that P. menziesii density and soil nutrient availability in the soil decreased with the distance from the plantation. In addition, an increase in native species cover was found after removing pines, but also noted the ability of P. menziesii to readily re-invade the native forest after removal. These results indicate the need for continuous control of P. menziesii , especially inside the native forest at the early stages of invasion. We discuss the need for better plantation management to prevent its spread into natural areas and protect native forests from non -native conifers invasion.
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    What fire didn't take away: plant growth-promoting microorganisms in burned soils of old-growth Nothofagus forests in Los Andes Cordillera
    (2024) Almonacid-Munoz, Leonardo; Herrera, Hector; Fuentes-Ramirez, Andres; Vargas-Gaete, Rodrigo; Toy-Opazo, Octavio; Costa, Paulo Henrique de Oliveira; Valadares, Rafael Borges da Silva
    Background and aims Wildfires can dramatically alter forests, their biodiversity and goods they provide to society. In the Andes Cordillera, Nothofagus pumilio is a native, fire-sensitive tree species that is completely excluded from severely burned areas. Therefore, it is of interest to evaluate whether there are differences in the microbial soil communities that could contribute to improve the recruitment of N. pumilio after a fire. We aimed at determining the diversity of soil bacteria and fungi associated with Nothofagus pumilio in old-growth forests affected by a moderate severity wildfire in the Andes Cordillera of south-central Chile in 2015. Methods Eight years after fire, soil samples were collected from selected N. pumilio rhizosphere and bulk soil in fire-affected areas, and were compared with those from unburned areas using a metabarcoding approach. Results We found that symbiotic microorganisms such as saprophytic, ectomycorrhizal fungi, ericoid mycorrhizal taxa and N-fixing bacteria were present with high abundances in the burned area. The most abundant bacterial genera were Mycobacterium, Rhodoplanes and Bryobacter. Meanwhile, Cortinarius and Penicillium were the most common fungal genera identified in burned and unburned sites. Conclusions Moderate severity wildfires in Nothofagus pumilio forests do not result in significantly different soil microbiomes eight years post-burn in either the rhizosphere or bulk soil, which could be key for N. pumilio establishment and survival after fire. Identifying the microbial diversity associated with native trees after fire is essential to know symbiotic microorganisms supporting the recovery of plant species.