Ecohydrological assessment of the water balance of the world's highest elevation tropical forest (Polylepis).

Polylepis trees grow at elevations above the continuous tree line (3000-5000 m a.s.l.) across the Andes. They tolerate extreme environmental conditions, making them sensitive bioindicators of global climate change. Therefore, investigating their ecohydrological role is key to understanding how the water cycle of Andean headwaters could be affected by predicted changes in environmental conditions, as well as ongoing Polylepis reforestation initiatives in the region. We estimate, for the first time, the annual water balance of a mature Polylepis forest (Polylepis reticulata) catchment (3780 m a.s.l.) located in the south Ecuadorian páramo using a unique set of field ecohydrological measurements including gross rainfall, throughfall, streamflow, and xylem sap flow in combination with the characterization of forest and soil features. We also compare the forest water balance with that of a tussock grass (Calamagrostis intermedia) catchment, the dominant páramo vegetation. Annual gross rainfall during the study period (April 2019-March 2020) was 1290.6 mm yr-1. Throughfall in the Polylepis forest represented 61.2 % of annual gross rainfall. Streamflow was the main component of the water balance of the forested site (59.6 %), while its change in soil water storage was negligible (<1 %). Forest evapotranspiration was 54.0 %, with evaporation from canopy interception (38.8 %) more than twice as high as transpiration (15.1 %). The error in the annual water balance of the Polylepis catchment was small (<15 %), providing confidence in the measurements and assumptions used to estimate its components. In comparison, streamflow and evapotranspiration at the grassland site accounted for 63.7 and 36.0 % of the water balance, respectively. Although evapotranspiration was larger in the forest catchment, its water yield was only marginally reduced (<4 %) in relation to the grassland catchment. The substantially higher soil organic matter content in the forest site (47.6 %) compared to the grassland site (31.8 %) suggests that even though Polylepis forests do not impair the hydrological function of high-Andean catchments, their presence contributes to carbon storage in the litter layer of the forest and the underlying soil. These findings provide key insights into the vegetation-water­carbon nexus in high Andean ecosystems, which can serve as a basis for future ecohydrological studies and improved management of páramo natural resources considering changes in land use and global climate.

Frontiers in páramo water resources research: A multidisciplinary assessment.

Interdisciplinary knowledge is necessary to achieve sustainable management of natural resources. However, research is still often developed in an exclusively disciplinary manner, hampering the capacity to holistically address environmental issues. This study focuses on páramo, a group of high-elevation ecosystems situated around ∼3000 to ∼5000 m a.s.l. in the Andes from western Venezuela and northern Colombia through Ecuador down to northern Peru, and in the highlands of Panama and Costa Rica in Central America. Páramo is a social-ecological system that has been inhabited and shaped by human activity since ∼10,000 years BP. This system is highly valued for the water-related ecosystem services provided to millions of people because it forms the headwaters of major rivers in the Andean-Amazon region, including the Amazon River. We present a multidisciplinary assessment of peer-reviewed research on the abiotic (physical and chemical), biotic (ecological and ecophysiological), and social-political aspects and elements of páramo water resources. A total of 147 publications were evaluated through a systematic literature review process. We found that thematically 58, 19, and 23 % of the analyzed studies are related to the abiotic, biotic, and social-political aspects of páramo water resources, respectively. Geographically, most publications were developed in Ecuador (71 % of the synthesized publications). From 2010 onwards, the understanding of hydrological processes including precipitation and fog dynamics, evapotranspiration, soil water transport, and runoff generation improved, particularly for the humid páramo of southern Ecuador. Investigations on the chemical quality of water generated by páramo are rare, providing little empirical support to the widespread belief that páramo environments generate water of high quality. Most ecological studies examined the coupling between páramo terrestrial and aquatic environments, but few directly assessed in-stream metabolic and nutrient cycling processes. Studies focused on the connection between ecophysiological and ecohydrological processes influencing páramo water balance are still scarce and mainly related to the dominant vegetation in the Andean páramo, i.e., tussock grass (pajonal). Social-political studies addressed páramo governance and the implementation and significance of water funds and payment for hydrological services. Studies directly addressing water use, access, and governance in páramo communities remain limited. Importantly, we found only a few interdisciplinary studies combining methodologies from at least two disciplines of different nature despite their value in supporting decision-making. We expect this multidisciplinary synthesis to become a milestone to foster interdisciplinary and transdisciplinary dialogue among individuals and entities involved in and committed to the sustainable management of páramo natural resources. Finally, we also highlight key frontiers in páramo water resources research, which in our view need to be addressed in the coming years/decades to achieve this goal.

Ventilación mecánica invasiva en COVID-19, ¿una estrategia mortal? / Invasive mechanical ventilation in COVID-19, a deadly strategy? / Ventilação mecânica invasiva no COVID-19, uma estratégia mortal?

Resumen Desde la epidemia de poliomielitis de Copenhague en 1952, los cuidados intensivos no habían enfrentado un desafío tan importante desde el punto de vista médico y mediático como la pandemia por COVID-19, la cual ha tenido consecuencias devastadoras; una de ellas es el desborde en la capacidad de las Unidades de Cuidados Intensivos y, como resultado, la posibilidad de ofrecer ventilación mecánica ha sido insuficiente; además, las características avasallantes y rápidamente cambiantes de la información médica y no médica, al igual que la mortalidad relacionada a la enfermedad, han desarrollado una narrativa deletérea al tratamiento de estos pacientes con apoyo ventilatorio invasivo, lo que ha hecho resurgir viejas cuestiones sobre ésta como lesiones inducidas por ventilación mecánica invasiva. Todo esto ha promovido la revivificación del apoyo ventilatorio no invasivo como medida salvadora; sin embargo, como veremos en esta aproximación a la luz de la evidencia, es errónea y puede resultar deletérea no sólo para el paciente, sino también para el personal de salud que cuida de éstos.

Abstract Since the Copenhagen polio epidemic in 1952, intensive care has not faced as important a challenge from a medical and media point of view as the COVID-19 pandemic, which has had devastating consequences, one of which is the overflow in the capacity of Intensive Care Units, and as a result of the capacity to offer mechanical ventilation has been insufficient, in addition to the overwhelming and rapidly changing characteristics of medical and non-medical information, also of disease-related mortality, has developed a deleterious narrative to the treatment of these patients with invasive ventilatory support and raising old questions about this as injuries induced by invasive mechanical ventilation. All this has promoted the rise of non-invasive ventilatory support as a saving lifes strategy, however, as we will see, this approach, in scope of the evidence, is erroneous and can be hazardous not only for the patient but also for health personnel who care for them.

Resumo Desde a epidemia de poliomielite em Copenhague em 1952, a terapia intensiva não enfrenta um desafio tão importante do ponto de vista médico e midiático como a pandemia de COVID-19, que teve consequências devastadoras, sendo uma delas o transbordamento da capacidade de terapia intensiva unidades, e com isso a possibilidade de oferta de ventilação mecânica tem sido insuficiente, além das características avassaladoras e em rápida mudança das informações médicas e não médicas, bem como a mortalidade relacionada à doença, desenvolveu uma narrativa deletéria ao tratamento da esses pacientes com suporte ventilatório invasivo e ressurgiu antigas questões sobre o mesmo, como as lesões induzidas pela ventilação mecânica invasiva. Tudo isso tem promovido o renascimento do suporte ventilatório não invasivo como medida de economia, porém, como veremos, essa abordagem, à luz das evidências, é errônea e pode ser deletéria não só para o paciente, mas também para o pessoal de saúde quem cuida deles.

Ventilación mecánica invasiva en COVID-19. ¿Una estrategia mortal? / Invasive mechanical ventilation in COVID-19, a deadly strategy? / Ventilação mecânica invasiva no COVID-19, uma estratégia mortal?

Resumen: Desde la epidemia de poliomielitis de Copenhague en 1952, los cuidados intensivos no habían enfrentado un desafío tan importante desde el punto de vista médico y mediático como la pandemia por COVID-19, la cual ha tenido consecuencias devastadoras; una de ellas es el desborde en la capacidad de las unidades de cuidados intensivos y como resultado la posibilidad de ofrecer ventilación mecánica ha sido insuficiente. Además, las características avasallantes y rápidamente cambiantes de la información médica y no médica, al igual que la mortalidad relacionada a la enfermedad, han desarrollado una narrativa deletérea al tratamiento de estos pacientes con apoyo ventilatorio invasivo y ha hecho resurgir antiguas interrogantes sobre las lesiones inducidas por ventilación mecánica invasiva. Todo esto ha promovido la revivificación del apoyo ventilatorio no invasivo como medida salvadora; sin embargo, como veremos esta aproximación es errónea a la luz de la evidencia y puede resultar deletérea no sólo para el paciente, sino para el personal de salud que cuida de éstos.

Abstract: Since the Copenhagen polio epidemic in 1952, intensive care has not faced as important a challenge from a medical and media point of view as the COVID-19 pandemic, which has had devastating consequences, one of which is the overflow in the capacity of intensive care units, and as a result of the capacity to offer mechanical ventilation has been insufficient, in addition to the overwhelming and rapidly changing characteristics of medical and non-medical information, also of disease-related mortality, has developed a deleterious narrative to the treatment of these patients with invasive ventilatory support and raising old questions about this as injuries induced by invasive mechanical ventilation. All this has promoted the rise of non-invasive ventilatory support as a saving lifes strategy, however, as we will see, this approach, in scope of the evidence, is erroneous and can be hazardous not only for the patient but also for health personnel who care for them.

Resumo: Desde a epidemia de poliomielite em Copenhague em 1952, a terapia intensiva não enfrenta um desafio tão importante do ponto de vista médico e midiático como a pandemia de COVID-19, que teve consequências devastadoras, sendo uma delas o transbordamento da capacidade das unidades de terapia intensiva, e como resultado a possibilidade de oferecer ventilação mecânica tem sido insuficiente. Além das características avassaladoras e a rápida mudança das informações médicas e não médicas, bem como a mortalidade relacionada à doença, desenvolveu-se uma narrativa deletéria ao tratamento da esses pacientes com suporte ventilatório invasivo e fez ressurgir antigas questões sobre o mesmo, como as lesões induzidas pela ventilação mecânica invasiva. Tudo isso tem promovido o renascimento do suporte ventilatório não invasivo como medida de salvadora, porém, como veremos, essa abordagem, à luz das evidências, é errônea e pode ser deletéria não só para o paciente, mas também para o pessoal de saúde quem cuida deles.

Progress in understanding the hydrology of high-elevation Andean grasslands under changing land use.

High-elevation grasslands worldwide provide essential hydrological services including water provision, flow regulation, and erosion control. Despite their importance, hydrological research of grasslands in montane regions is usually scarce and disperse, limiting the capacity to improve water resource management. We present a systematic literature review of the hydrological function of high Andean grasslands under conserved, degraded, and restored conditions in ecosystems situated above the tree line in the tropical Andes (páramos, punas, and jalcas). Most hydrological research on these grasslands has been developed in páramos (92%), especially in Ecuador, while research in punas is scarce (6%) despite being the largest grassland extent in the region. For páramos, published literature highlights the importance of conserving grasslands to facilitate water infiltration to soils, which in turn reduces erosive processes. Water-vegetation relations for conserved páramos are well understood, indicating that about 50% of water inputs return to the atmosphere via evapotranspiration, but knowledge about hydrological functions of conserved punas and jalcas is virtually non-existent. Under changing land use, afforestation of grassland ecosystems with exotic tree species, especially pines, reduces soil water storage as well as water yield and flow regulation capacity. Impacts of grazing and agriculture on the hydrological function of páramo grasslands strongly depend on historical land management and current land use practices and are not generalizable. Short-term restoration studies indicate that more than two years are necessary to recover the hydrological function of degraded grasslands, therefore medium and long-term studies are required to determine efficient restoration periods. These knowledge gaps limit the ability to extrapolate and regionalize findings. Future directions aimed to fill them are proposed, and methods successfully used to investigate the hydrology of high Andean grasslands are highlighted. This research not only enlightens what is known about the hydrology of high Andean grasslands, but also seeks to guide future hydrological evaluations to fill identified geographical and topical knowledge gaps precluding improved management of water resources in the tropical Andes.