Browsing by Autor "Fuentes, Alfredo F."

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Comment on egusphere-2025-2032
(2025) Oelkers, Rose; Andreu-Hayles, Laia; D'Arrigo, Rosanne; Pacheco Solana, Arturo; Rodriguez-Caton, Milagros; Ferrero, M. Eugenia; Tejedor, Ernesto; Fuentes, Alfredo F.; Maldonado, Carla; Ruiz-Carrascal, Daniel
Abstract. Relative to research efforts in higher latitiudes, the impact of climate shifts in the tropical treeline remains understudied. Little is known about the tree growth dynamics and climate response at this treeline over the past few centuries, and at present under a rapidly changing environment. Here we provide information on recent changes in tree-ring patterns of Polylepis pepei BB.Simpson, a tropical tree species that grows in a monospecific forest at the elevational treeline in the Andes-Amazon ecotone of Bolivia and identify factors that limit its radial growth. We first developed a ring width (RW) chronology spanning 1867–2018 C.E. using dendrochronological methods and independently verified annual periodicity with radiocarbon dating. The RW chronology indicates a significant (p < 0.01) radial growth decline in P. pepei since 1997, a trend that mirrors a decrease reported in other Polylepis species from the drier central Andes of South America. P. pepei tree-ring width (RW) was mostly limited by mean, minimum, and maximum temperature and precipitation during austral summer (November–January). Over the instrumental period (1981–2019) prior-year temperatures negatively affected current-year tree growth (p < 0.05), while prior-year wet conditions were associated with higher growth (p < 0.05). Gridded temperature records (1901–2019) showed a significant increase in minimum temperatures and a decline in the diurnal temperature range since 1967, which may reduce orographic convection and water availability at higher elevations where our forest is located. In situ daily measurements from dataloggers in the forest recorded higher temperatures and lower relative humidity values when data was available. Our results suggest less moisture availability associated with warming conditions was related to the observed tree-growth decline. If temperature continues to rise at current rates, one of the highest-elevation tree species on the globe, P. pepei, could face severe consequences. This work provides insights into the past and historical trends of a tropical Andean treeline, which shows a recent decline also observed in other high-elevation forests (4657–4800 m.a.s.l.) of tropical South America (>17° S).
Comment on egusphere-2025-2032
(2025) Oelkers, Rose; Andreu-Hayles, Laia; D'Arrigo, Rosanne; Pacheco Solana, Arturo; Rodriguez-Caton, Milagros; Ferrero, M. Eugenia; Tejedor, Ernesto; Fuentes, Alfredo F.; Maldonado, Carla; Ruiz-Carrascal, Daniel
Abstract. Relative to research efforts in higher latitiudes, the impact of climate shifts in the tropical treeline remains understudied. Little is known about the tree growth dynamics and climate response at this treeline over the past few centuries, and at present under a rapidly changing environment. Here we provide information on recent changes in tree-ring patterns of Polylepis pepei BB.Simpson, a tropical tree species that grows in a monospecific forest at the elevational treeline in the Andes-Amazon ecotone of Bolivia and identify factors that limit its radial growth. We first developed a ring width (RW) chronology spanning 1867–2018 C.E. using dendrochronological methods and independently verified annual periodicity with radiocarbon dating. The RW chronology indicates a significant (p < 0.01) radial growth decline in P. pepei since 1997, a trend that mirrors a decrease reported in other Polylepis species from the drier central Andes of South America. P. pepei tree-ring width (RW) was mostly limited by mean, minimum, and maximum temperature and precipitation during austral summer (November–January). Over the instrumental period (1981–2019) prior-year temperatures negatively affected current-year tree growth (p < 0.05), while prior-year wet conditions were associated with higher growth (p < 0.05). Gridded temperature records (1901–2019) showed a significant increase in minimum temperatures and a decline in the diurnal temperature range since 1967, which may reduce orographic convection and water availability at higher elevations where our forest is located. In situ daily measurements from dataloggers in the forest recorded higher temperatures and lower relative humidity values when data was available. Our results suggest less moisture availability associated with warming conditions was related to the observed tree-growth decline. If temperature continues to rise at current rates, one of the highest-elevation tree species on the globe, P. pepei, could face severe consequences. This work provides insights into the past and historical trends of a tropical Andean treeline, which shows a recent decline also observed in other high-elevation forests (4657–4800 m.a.s.l.) of tropical South America (>17° S).
Data from: Influence of bracken fronds and leaf litter management on soil seed bank characteristics in a fire-disturbed tropical montane forest
(2025) Jimenez, Emili A.; Lopez, Cecilia L.; Fuentes, Alfredo F.; Hensen, Isabell; Gallegos, Silvia C.
The bracken fern Pteridium spp. dominates post-fire vegetation in tropical montane forests, where fronds, litter, allelopathy, and dispersal limitation hinder forest regeneration. However, this species’ effect on soil seed bank remains poorly understood. We investigated the effects of bracken fronds and litter on the abundance, richness, and species diversity of the soil seed bank in a tropical montane fire-deforested area in Bolivia. At eight study sites (1,800-2,350 m.a.s.l), soil samples were collected under five treatments: (a) fronds and litter intact (F+L+), (b) fronds intact and litter removed (F+L-), (c) fronds removed and litter intact (F-L+), (d) fronds and litter removed (F-L-), and (e) forest. Using the seedling emergence method, samples were assessed every 20 days over eight months (September 2021- May 2022). Compared to intact bracken, forest areas showed 2.6, 1.7, and 1.5-fold greater abundance, species richness, and diversity of zoochorous species, respectively. Among bracken treatments, abundance, richness, and diversity of zoochorous species decreased by 2.7, 2.6, and 2 times, respectively, when fronds and litter were removed, compared to the intact bracken treatment, but were not significantly different when only litter was removed. Our findings indicate that in bracken-dominated environments, fronds and litter improve microclimatic conditions, there by maintaining the viability of zoochorous species in the soil seed bank. The removal of litter without cutting fronds reduces light interception and seed trapping, while maintaining zoochorous seed germination capacity in the soil, and might be a better management strategy than removing fronds and litter to promote seedling recruitment from the soil seed bank.
Data from: Trait-based species selection for restoration: A case study from tropical landscapes dominated by bracken
(2025) Gallegos, Silvia C.; López, Cecilia L.; Naoki, Kazuya; Soliz, Andrea; Fuentes, Alfredo F.; Mayta, Cesar; Cayola, Leslie; Tello, J. Sebastian; Hensen, Isabell
Deforestation leads to non-forested areas that often need active ecological restoration to promote forest succession. Here, we developed a trait-based approach to guide the design of restoration projects and tested our approach in tropical areas deforested by fires and dominated by bracken. Deforestation caused by human-induced fires creates complex conservation problems in tropical areas. After fire, montane tropical deforested areas are often dominated by bracken fern (Pteridium spp.), which prevents the establishment of many species of trees. This means that effective ecological restoration strategies are needed for forest recovery. We explored whether a trait-based approach could be used to guide the selection of tree species in active restoration projects in deforested areas. We first tested whether traits could be used to predict which species can overcome bracken-associated filters. We then tested the relationship between the trait-based predictions for each species and their abundance in a reference old-growth forest. To identify key traits, we conducted a seed addition experiment in bracken-dominated areas that had developed 5-15 years after a fire, using 23 tree species common in the Bolivian montane forests, and monitored seedling establishment, survival, and growth for 36 months. We then related seedling performance to the functional traits of adults and seedlings. We found that six functional traits improved tree seedling performance in bracken-dominated areas, and that only one-third of the species evaluated exceeded a 25% probability of recruitment. Most of the favored traits correspond to conservative strategies. The species dispersed by birds and with large seeds were the most likely to overcome the filters created by bracken. Based on the trait predictions, we found that the species predicted to overcome bracken are not common in old-growth forests. Our results can be used by stakeholders to select the species best suited for active restoration projects in bracken-dominated areas throughout the tropical region. Furthermore, our trait-based approach, which considers seedling performance in disturbed areas, can serve as a guide for species selection in restoration programs in other disturbed systems.
La achacana (Neowerdermannia vorwerkii, Cactaceae) nuevo registro para el Valle de La Paz
(Ecología en Bolivia, 2023) Velarde-Simonini, Luis F.; Fuentes, Alfredo F.; Quino-Soliz, Jhonatan
La importancia de las plantas medicinales, su taxonomía y la búsqueda de la cura a la enfermedad que causa el coronavirus (COVID-19)
(Ecología en Bolivia, 2020) Maldonado, Carla; Paniagua-Zambrana, Narel; Bussmann, Rainer W.; Zenteno-Ruiz, Freddy S.; Fuentes, Alfredo F.
Los bosques montanos húmedos de la serranía de Apa-Apa (Sud Yungas, La Paz, Bolivia): Un centro de diversidad de plantas y fuente esencial de agua
(Ecología en Bolivia, 2024) Beck, Stephan G.; Fuentes, Alfredo F.; López, Cecilia L.; Cuba-Orozco, Elmer; Gallegos, Silvia C.
El bosque montano húmedo tropical de los Andes centrales, conocido como los Yungas, alberga alta biodiversidad, pero los estudios acerca de las especies que lo componen son aún escasos. Un área de particular importancia es la serranía de Apa-Apa en Sud Yungas (La Paz, Bolivia). Los objetivos de esta reseña son a) presentar una lista taxonómicamente actualizada de las especies de plantas vasculares de los bosques montanos húmedos y áreas perturbadas de la serranía de Apa-Apa; b) cuantificar las especies endémicas y amenazadas e identificar algunas especies útiles; c) clasificar, caracterizar y cartografiar los tipos de vegetación de la zona; d) describir la flora en los diferentes tipos de vegetación; y e) resaltar la importancia de la conservación de estos bosques en términos de biodiversidad y del bienestar de las poblaciones locales. A lo largo de 40 años se realizaron colectas en la serranía, principalmente entre 1.800-2.600 m. Identificamos 1.439 especies de plantas vasculares, de las cuales 151 destacan como endémicas y 80 como nuevas para la ciencia, mostrando la alta riqueza de la serranía. Encontramos cuatro grupos vegetales principales: los bosques montanos húmedos, los bosques estacionales húmedos, los bosques estacionales subhúmedos y los bosques xéricos secos, además de la vegetación secundaria. Este estudio proporciona una base fundamental para futuras investigaciones y esfuerzos de conservación en la zona. Destacamos la importancia de promover la conservación de estos bosques tanto para mantener su gran diversidad, como para garantizar el acceso al agua a los pobladores locales.
Relaciones fitogeográficas de las sabanas montanas de Apolo en la región Madidi, con sabanas neotropicales. La Paz, Bolivia
(Ecología en Bolivia, 2010) Miranda, Tatiana; Fuentes, Alfredo F.; Jørgensen, Peter M.; Stephan G., Beck