Browsing by Author "Fuentes-Ramirez, Andres"

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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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    Fire Severity Causes Temporal Changes in Ground-Dwelling Arthropod Assemblages of Patagonian Araucaria-Nothofagus Forests
    (2022) Zuniga, Alfredo H.; Rau, Jaime R.; Fierro, Andres; Vergara, Pablo M.; Encina-Montoya, Francisco; Fuentes-Ramirez, Andres; Jaksic, Fabian M.
    Fire is one of the main drivers of anthropogenic disturbances in temperate forest ecosystems worldwide, with multiple effects spread across ecological networks. Nevertheless, the biodiversity effects of fire are poorly known for species-diverse groups such as arthropods. In this research, we used a burn gradient generated two and three years after a large fire event to assess how different levels of fire severity affect arthropod diversity in the forest with the main forest forming long-living tree species Araucaria araucana, in southern Chile. The species richness and abundance of arthropods among trophic guilds was estimated annually in four fire-severity levels. We found that arthropods responded differently to fire severity levels, depending on their trophic guilds and years after fire (two and three years after fire). During the second year after fire, zoophages, phytophages, and parasitoids were more diverse in areas with high fire severity within the second year after fire, as compared to those in areas with low severity or unburned stands. In the third year after fire, a change in this trend was observed, where the abundance of all groups dropped significantly, with positive changes in the diversity in zoophages, phytophages, polyphages and saprophages, which is more noticeable in sites with high severity. These results indicate that annual variation in environmental conditions triggers bottom-up cascading effects for arthropods. Forests stands severely impacted by fires support highly fluctuating and possibly unstable arthropod assemblages. Hence, restoration efforts should be focused on recovering microhabitat conditions in these stands to allow the persistence of arthropods.
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    Native bamboo increases biotic resistance to Pinus contorta invasion in temperate forest ecosystems
    (2023) Ulloa, Javier; Fuentes-Lillo, Eduardo; Fuentes-Ramirez, Andres; Pauchard, Anibal; Garcia, Rafael A.
    One of the tree species with the greatest invasive potential worldwide is Pinus contorta Douglas ex Loundon, which is characterized by producing a great number of individuals in short periods of time, generating different impacts on the ecosystems it invades. The genus Chusquea is present in a diverse number of ecosystems in South America. In the temperate forests of Chile and Argentina, it forms dense thickets in the undergrowth as well as in open areas. Its rapid growth and vegetative reproduction, with large numbers of individuals, allow the species to dominate and restrict the establishment of other plant species. This study focused on analyzing the effect of the presence of individuals of Chusquea culeou E. Desv. on the establishment of the invasive species Pinus contorta, as well as on other native herbaceous and shrub species in Araucaria-Nothofagus forest. With this aim, we established 204 plots within the Malalcahuello National Reserve (in the Andes of south-central Chile) along a gradient of P. contorta invasion, where the presence or absence of these species was recorded through different percentages of Chusquea cover. The results showed that the probability of presence of P. contorta decreases significantly in areas where Chusquea cover is greater than 25%. Native species also decrease their presence, but to a lesser extent compared to P. contorta. Our results demonstrate the inhibitory effect of Chusquea for the establishment of other plant species, but more markedly for invasive conifers.
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    Spatio-Temporal Variation in Soil Nutrients and Plant Recovery across a Fire-Severity Gradient in Old-Growth Araucaria-Nothofagus Forests of South-Central Chile
    (2022) Fuentes-Ramirez, Andres; Almonacid-Munoz, Leonardo; Munoz-Gomez, Nayadeth; Moloney, Kirk A.
    Forest fires can alter essential ecosystem processes, including soil nutrient cycling, potentially cascading into permanent vegetation changes. This is key to elucidate in ecosystems where fires are infrequent. We assessed the effects of fire severity on the spatio-temporal response of soil nutrients and plant diversity in old-growth forests of south-central Chile, 1, 2, and 3 years after a fire that occurred in 2015. Within ancient, old-growth Araucaria araucana (Mol.) K. Koch and Nothofagus pumilio (Poepp. and Endl.) Krasser forests, ranging from areas burned with fire of high severity to unburned forests, we evaluated nitrogen (N), phosphorus (P), potassium (K), and soil organic matter (SOM) content using spatial interpolation to predict their spatial distribution and assessed their availability over time. We also assessed plant species richness and abundance following the fire. The availability of N noticeably increased during the first year after fire but rapidly decreased in the following years, especially in areas of high fire severity. P, K, and SOM were less affected by the fire, remaining more constant over time. In the short term, plant species richness and diversity significantly decreased in severely burned areas, but over time, they became more similar to those of the unburned forests. The time since a fire and its severity determine a heterogeneous distribution of soil nutrients, with N shifting to a significantly lower availability after fire, which was more notable in areas of high fire severity. Here, vegetation exhibited a decrease in plant diversity and the establishment of exotic species, likely producing cascading effects at the community level.
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    The effect of natural disturbances on forest biodiversity: an ecological synthesis
    (2022) Viljur, Mari-Liis; Abella, Scott R.; Adamek, Martin; Alencar, Janderson Batista Rodrigues; Barber, Nicholas A.; Beudert, Burkhard; Burkle, Laura A.; Cagnolo, Luciano; Campos, Brent R.; Chao, Anne; Chergui, Brahim; Choi, Chang-Yong; Cleary, Daniel F. R.; Davis, Thomas Seth; Dechnik-Vazquez, Yanus A.; Downing, William M.; Fuentes-Ramirez, Andres; Gandhi, Kamal J. K.; Gehring, Catherine; Georgiev, Kostadin B.; Gimbutas, Mark; Gongalsky, Konstantin B.; Gorbunova, Anastasiya Y.; Greenberg, Cathryn H.; Hylander, Kristoffer; Jules, Erik S.; Korobushkin, Daniil I.; Koster, Kajar; Kurth, Valerie; Lanham, Joseph Drew; Lazarina, Maria; Leverkus, Alexandro B.; Lindenmayer, David; Marra, Daniel Magnabosco; Martin-Pinto, Pablo; Meave, Jorge A.; Moretti, Marco; Nam, Hyun-Young; Obrist, Martin K.; Petanidou, Theodora; Pons, Pere; Potts, Simon G.; Rapoport, Irina B.; Rhoades, Paul R.; Richter, Clark; Saifutdinov, Ruslan A.; Sanders, Nathan J.; Santos, Xavier; Steel, Zachary; Tavella, Julia; Wendenburg, Clara; Wermelinger, Beat; Zaitsev, Andrey S.; Thorn, Simon
    Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human-induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land-use change. Conversely, the suppression of natural disturbances threatens disturbance-dependent biota. Using a meta-analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on alpha-diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground-dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest alpha-diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta-analysis by applying a unified diversity concept based on Hill numbers to estimate alpha-diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity-disturbance relationships are shaped by species relative abundances. Our synthesis of alpha-diversity was extended by a synthesis of disturbance-induced change in species assemblages, and revealed that disturbance changes the beta-diversity of multiple taxonomic groups, including some groups that were not affected at the alpha-diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape.
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    Tree Cover Species Modify the Diversity of Rhizosphere-Associated Microorganisms in Nothofagus obliqua (Mirb.) Oerst Temperate Forests in South-Central Chile
    (2022) Almonacid-Munoz, Leonardo; Herrera, Hector; Fuentes-Ramirez, Andres; Vargas-Gaete, Rodrigo; Larama, Giovanni; Jara, Ronald; Fernandez-Urrutia, Camila; da Silva Valadares, Rafael Borges
    Chilean native forests have been subjected to several types of disturbances, with one of them being the replacement by exotic species. Pinus radiata D. Don is a widespread exotic tree that forms extensive plantations in southern Chile. It covers extended areas, affecting the landscape, biodiversity, and ecosystem services associated with native forest ecosystems. Although advances in assessing the impact of exotic plant species have been conducted, few studies have focused on the alteration of soil microorganisms. This study aimed to characterize the rhizosphere bacterial and fungal communities associated with the tree species Nothofagus obliqua inside a native forest stand and within a P. radiata plantation growing nearby. We used a 16S rRNA gene and ITS region metabarcoding approach. Using bioinformatics, diversity indices, relative abundance, preferential taxa, and predicted functions and guilds were estimated. The beta-diversity analysis showed that both factors, the type of soil (rhizosphere or bulk soil) and the type of site (native forest or P. radiata plantation), were significant, with the site explaining most of the variation among bacterial and fungal communities. Proteobacteria and Basidiomycota were the most abundant bacterial and fungal phyla in both types of soil and sites. Similarly, bacteria showed similar abundant taxa at the family level, independent of the soil type or the site. The main fungal taxa associated with native forests were Tricholomataceae and Cantharellales, whereas in P. radiata plantations, Russulaceae and Hyaloscyphaceae were the most abundant families. The main bacteria functional groups were chemoheterotrophy and aerobic chemoheterotrophy, without significant differences between the type of soil or sites. Overall, these results demonstrate that the composition and diversity of bacterial and fungal communities associated with native N. obliqua forest are influenced by the surrounding forest, and mainly depend on the site's characteristics, such as the lignin-rich wood source. These results improve our understanding of the impact of native forest replacement on soil microbial communities, which can alter microbial-related soil ecosystem services.
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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.