Browsing by Autor "Fernando D. Alfaro"

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Climatic vulnerabilities and ecological preferences of soil invertebrates across biomes
(Wiley, 2019) Felipe Bastida; David J. Eldridge; Sebastián Abades; Fernando D. Alfaro; Antonio Gallardo; Laura García‐Velázquez; Carlos Garcı́a; Stephen C. Hart; Cecilia A. Pérez; Fernanda Santos
Unlike plants and vertebrates, the ecological preferences, and potential vulnerabilities of soil invertebrates to environmental change, remain poorly understood in terrestrial ecosystems globally. We conducted a cross-biome survey including 83 locations across six continents to advance our understanding of the ecological preferences and vulnerabilities of the diversity of dominant and functionally important soil invertebrate taxa, including nematodes, arachnids and rotifers. The diversity of invertebrates was analyzed through amplicon sequencing. Vegetation and climate drove the diversity and dominant taxa of soil invertebrates. Our results suggest that declines in forest cover and plant diversity, and reductions in plant production associated with increases in aridity, can result in reductions of the diversity of soil invertebrates in a drier and more managed world. We further developed global atlases of the diversity of these important soil invertebrates, which were cross-validated using an independent database. Our study advances the current knowledge of the ecological preferences and vulnerabilities of the diversity and presence of functionally important soil invertebrates in soils from across the globe. This information is fundamental for improving and prioritizing conservation efforts of soil genetic resources and management policies.
Exclusion of small mammals and lagomorphs invasion interact with human-trampling to drive changes in topsoil microbial community structure and function in semiarid Chile
(Elsevier BV, 2018) Fernando D. Alfaro; Marlene Manzano; Sebastián Abades; Nicole Trefault; Rodrigo De la Iglesia; Aurora Gaxiola; Pablo A. Marquet; Julio R. Gutiérrez; Peter L. Meserve; Douglas Kelt
Functional stratification and enzymatic arrangement in microbial communities across a hypersaline depth gradient
(Frontiers Media, 2025) C. Hoepfner; Daniel Guzmán; Boris Vidal‐Veuthey; V. Foronda; Antonia Beggs; Juan Pablo Cárdenas; Virginia A. Vargas; Fernando D. Alfaro
Extreme environments comprise a significant portion of Earth's terrestrial surface, posing challenges, such as extreme temperatures, pressure, pH extremes, oxygen and nutrient scarcity, and high salinity. Hypersaline ecosystems, such as those in the Andean Cold Deserts, exemplify extreme environments where microbial life has evolved specialized survival mechanisms. The Central Andean Mountains host extensive salt flats exposed to extreme temperature fluctuations, intense ultraviolet radiation, and high soil salinity. While most studies focus on surface layers, the impact of soil depth on functional diversity remains poorly understood. This study utilized shotgun metagenomics and functional annotation to explore enzymatic diversity across a 8-meter depth gradient in the Uyuni Salt Flat aiming to understand microbial adaptations to depth and abiotic stress. Our findings revealed a complex, stratified microbial ecosystem. Surface layers showed high abundance of amylases, enzymes that degrade accessible carbohydrates, likely derived from photosynthetic communities or surface-imported organic matter. These patterns suggest a dominance of strategies for rapid carbon decomposition. Intermediate depths exhibited elevated lipase and peroxidase activity, reflecting the presence of complex lipids and oxidative stress management, essential for survival in oxygen-limited, high-salinity zones. Lipase support lipid utilization as a carbon source, while peroxidase activity points to redox adaptations for microbial resilience under fluctuating oxidative conditions. Deeper sediment layers showed a shift toward protease and peptidase activity, indicating organic nitrogen recycling in nutrient-deprived environments and suggesting an efficient protein degradation system among halophilic archaea. Peroxidases remained abundant even at these depths, supporting sustained redox regulation and biogeochemical cycling thus enabling microbes to manage redox imbalances in high-salinity, low-oxygen settings. The enzymatic diversity across the depth gradient demonstrates functional stratification and remarkable microbial adaptability to hypersaline conditions. This functional resilience underpins nutrient cycling and organic matter decomposition deep in the salt flats. Notably, the identified halophilic enzymes, stable and active under high-salinity conditions, hold significant potential for biotechnological applications. This study contributes to our understanding of microbial life's complexity in hypersaline environments, enhancing our ability to harness extremophilic enzymes for biotechnological applications while underscoring the ecological value of these unique habitats.
Global ecological predictors of the soil priming effect
(Nature Portfolio, 2019) Felipe Bastida; Carlos Garcı́a; Noah Fierer; David J. Eldridge; Matthew A. Bowker; Sebastián Abades; Fernando D. Alfaro; Asmeret Asefaw Berhe; Nick A. Cutler; Antonio Gallardo
Microbial communities in soil chronosequences with distinct parent material: the effect of soil <scp>pH</scp> and litter quality
(Wiley, 2017) Fernando D. Alfaro; Marlene Manzano; Pablo A. Marquet; Aurora Gaxiola
Summary During soil development, bacteria and fungi can be differentially affected by changes in soil biogeochemistry. Since the chemistry of parent material affects soil pH , nutrient availability, and indirectly litter quality, we hypothesize that parent material has an important influence on microbial community patterns during long‐term soil development. In this paper, we tested for the effect of parent material, as well as, soil and litter properties upon microbial community patterns in three c. 20 000‐year‐old semi‐arid chronosequences developed on sedimentary and volcanic (i.e. Andesitic and Dacitic) soils in the Dry Puna of Bolivia. We evaluated microbial patterns by analysing the terminal restriction fragment length polymorphism from amplified bacterial 16S rRNA genes, and the fungal internal transcribed spacer region, and quantitative real‐time polymerase chain reaction. Soil and litter characteristics differed significantly between the Sedimentary and volcanic chronosequences. In particular, soil pH was alkaline in all stages of the Sedimentary chronosequence; whereas it changed from alkaline to near neutral across stages in both volcanic chronosequences. Composition of bacterial communities changed across volcanic chronosequences, and this change was associated with a reduction in soil pH and increases in litter quality, whereas no differences were found in the Sedimentary chronosequence. Fungal community composition, in contrast, did not change across any chronosequence. Relative microbial abundance, expressed as the fungal:bacterial ratio, declined across stages of the Sedimentary chronosequence in association with decreases in TC and TP , whereas in the Andesitic chronosequence decreases in fungal:bacterial ratios were related with increases in litter quality and declines in soil pH . Synthesis . Our results show the importance of parent material in affecting bacterial and fungal communities during soil development. Further, in semi‐arid chronosequences, fungal:bacterial ratios tend to decline given that soil pH in young soils is rather alkaline. Our results also are consistent with the general framework that highlights the importance of above‐ground (i.e. litter quality) and below‐ground (i.e. soil properties) in affecting microbial relative abundance and community composition during soil development.
Plant communities on the islands of two Altiplanic salt lakes in the Andean region of Bolivia
(Pensoft Publishers, 2016) Alejandro Coca‐Salazar; Huber Villca; Mauricio Torrico; Fernando D. Alfaro
This paper reports a quantitative survey of the composition, diversity and structure of the plant communities on six islands of Uyuni and Coipasa salt lakes (Bolivia). Plant communities on each island were examined via the use of 10 transects, along which species richness and abundance were recorded. Seventy-one species were found in total, representing pteridophytes (6%), gymnosperms (1%), monocotyledons (14%) and dicotyledons (79%). About 21% of the species were endemic or faced some degree of threat. The calculation of Shannon-Wiener α-diversity indices and comparisons of community structure revealed similarities between the islands. Indeed these analyses suggest the existence of a single floral assemblage; however, small differences in the plant communities were visually identified during fieldwork. These islands are home to a considerable subset of the Altiplano’s flora and appear to have been little disturbed. They should therefore be the subject of surveillance/conservation programs.
Sociality of<i>Octodontomys gliroides</i>and other octodontid rodents reflects the influence of phylogeny
(Oxford University Press, 2014) Daniela S. Rivera; Sebastián Abades; Fernando D. Alfaro; Luis A. Ebensperger
Multiple ecological factors are known to drive variation in social behavior. However, group-living in some species appears to be highly conserved, suggesting a phylogenetic influence. In this study, we evaluated both scenarios using intraspecific and interspecific comparisons across octodontid rodents. We first examined 2 different populations of Andean degu (Octodontomys gliroides), representing 2 extremes of a climate vegetation gradient across the Andes range. We evaluated how ecological variation in terms of abundance and distribution of food resources, predation risk, and burrowing costs predicted interpopulation variation in group size and range-area overlap (2 proxies of sociality). We estimated these measures of sociality from livetrapping and radiotelemetry. We then used phylogenetic methods to determine whether sociality exhibits a phylogenetic signal and reconstructed the ancestral state of sociality across the family Octodontidae. Overall activity of females and males of O. gliroides was greater during nighttime than daytime. Across populations we found significant differences in ecology, including abundance and distribution of food, predation risk, and burrowing costs. However, populations were similar in terms of group size and range-area overlap. The phylogenetic approach revealed a strong and significant phylogenetic signal associated with sociality, where this behavior was present early during the evolution of octodontid rodents. Together, these findings imply that sociality of O. gliroides is not linked to current population differences in ecology.
The impact of Polylepis tarapacana on soil microbial communities in the Andean Dry Puna of Chile
(Elsevier BV, 2025) Ignacio Gutiérrez-Cortés; Stephen D. Simpson; Marlene Manzano; Huber Villca; Bárbara Monteiro de Castro e Castro; Jean‐Baptiste Ramond; María del Pilar Fernández Murillo; Fernando D. Alfaro
Trypanosoma cruzi (Kinetoplastida Trypanosomatidae): Ecology of the transmission cycle in the wild environment of the Andean valley of Cochabamba, Bolivia
(Elsevier BV, 2006) Mirko Rojas Cortez; Ana Paula Pinho; Patrícia Cuervo; Fernando D. Alfaro; Marco Solano; Samanta Cristina das Chagas Xavier; Paulo Sérgio D’Andrea; Octavio Fernandes; Faustino Torrico; François Noireau