Browsing by Author "Carabajo Hidalgo, Aldemar Emmanuel"

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Brief windows with more favorable atmospheric conditions explain patterns of Polylepis reticulata tree water use in a high-altitude Andean forest
(2023) Carabajo Hidalgo, Aldemar Emmanuel; Crespo Sánchez, Patricio Javier
Polylepis trees occur throughout the Andean mountain region, and it is the tree genus that grows at the highest elevation worldwide. In the humid Andes where moisture is rarely limiting, Polylepis trees must adapt to extreme environmental conditions, especially rapid fluctuations in temperature, ultraviolet radiation and vapor pressure deficit (VPD). However, Polylepis’ water-use patterns remain largely unknown despite the importance of understanding their response to microclimate variation to determine their capacity to maintain resilience under future environmental change. We conducted a study in a Polylepis reticulata Kunth forest in the Ecuadorian Andes to evaluate its tree water-use dynamics and to identify the main environmental drivers of transpiration. Tree sap flow was monitored simultaneously with soil volumetric water content (VWC) and microclimate during 2 years for trees growing in forest edge and interior locations. We found that sap flow was primarily controlled by VPD and that VWC exerted a secondary role in driving sap flow dynamics. The highest values for sap flow rates were found when VPD > 0.15 kPa and VCW < 0.73 cm3 cm−3, but these threshold conditions only occurred during brief periods of time and were only found in 11% of our measurements. Moreover, these brief windows of more favorable conditions occurred more frequently in forest edge compared with forest interior locations, resulting in edge trees maintaining 46% higher sap flow compared with interior trees. Our results also suggest that P. reticulata has a low stomatal control of transpiration, as the sap flow did not decline with increasing VPD. This research provides valuable information about the potential impacts of projected future increases in VPD due to climate change on P. reticulata water-use dynamics, which include higher sap flow rates leading to greater transpirational water loss due to this species’ poor stomatal control.The main research question this paper seeks to answer is “What key factors are used to design BSSs?” those factors are supported by criteria such as methods for interpreting and using data from several sources. In this context, both automatic and manual searches for literature were conducted, resulting in 96 studies related to the design of a BSS being included in this review. The methodology used objectively assesses the research topic in a reliable, repeatable, and replicable manner. It allows us to determine what factors, methods, and data were used in the strategic planning of the BSS design. The review results show that although many solutions to problems have been devised, gaps need to be filled in this research field. This study aims to help researchers detect weaknesses and gaps and open new horizons regarding the BSS long-term design.
Cómo avanzar en la conservación de los bosques de Polylepis y su diversidad biológica?
(2021) Segovia Salcedo, Maria Claudia
Polylepis is the dominant genus of the high Andean forest vegetation and they have a crucial ecological role. However, these forests are highly endangered and many of their biological aspects are still unknown. In this context, a series of questions were formulated with the aim that their resolution would contribute to a better understanding of Polylepis’dynamics and biological diversity, as well as improve their conservation efforts. Twenty one speakers from the V International Congress of Conservation and Ecology of Polylepis forests participated in the formulation of 67 questions related to these forests. Comments and additional information were received via email and google doc spreadsheet, open to the participants. Afterwards, two workshops were organized with the researchers to formulate, discuss, analyze and define the final list, narrowing down to a total of 40 questions. The questions were categorized into 6 different topics: Taxonomy, Ecology and Biogeography, Genetics, Conservation, Ethnobiology and Climate Change. We hope these questions will be considered as a priority for new research agendas and to define joint efforts for Polylepis forest conservation. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
Efectos de las condiciones meteorológicas extremas en los patrones de los ciclos diarios de los árboles de Polylepis reticulata
(Universidad de Cuenca, 2025-03-25) Poma Tene, Byron Rodrigo; Carabajo Hidalgo, Aldemar Emmanuel
Polylepis forests grow in the high Andes, forming the world's highest tree line while adapting to extreme climatic conditions. Despite their ecological significance, the daily patterns of stem cycles remain understudied. From 2018 to 2022, we monitored a Polylepis reticulata forest in the Ecuadorian Andes, utilizing high-resolution dendrometers to assess stem cycle responses to climatic events in large (LD) and small (SD) diameter classes. A peak threshold approach identified extreme events based on vapor pressure deficit (VPD). We employed multiple linear regression (MLR) to pinpoint key environmental factors influencing daily maximum stem shrinkage (MDS) and used random forest (RF) and regression tree (RT) techniques to determine growth drivers. During cold events, stem shrinkage was minimal, contributing 30% to annual growth, whereas warm events exhibited pronounced shrinkage, contributing less than 1%. The primary driver of MDS was maximum daily VPD, followed by precipitation. VPD is the main driver in radial growth, when VPD is <0.048 kPa higher growth rate was observed. The various responses to extreme conditions and the drivers of stem fluctuation provide key information on the possible impacts on these forests, affecting their development and adaptive capacity in the future.