Vicuña antipredator diel movement drives spatial nutrient subsidies in a high Andean ecosystem.

Large animals could be important drivers of spatial nutrient subsidies when they ingest resources in some habitats and release them in others, even moving nutrients against elevational gradients. In high Andean deserts, vicuñas (Vicugna vicugna) move daily between nutrient-rich wet meadows, where there is abundant water and forage but high risk of predation by pumas (Puma concolor), and nutrient-poor open plains with lower risk of predation. In all habitats, vicuñas defecate and urinate in communal latrines. We investigated how these latrines impacted soil and plant nutrient concentrations across three habitats in the Andean ecosystem (meadows, plains, and canyons) and used stable isotope analysis to explore the source of fecal nutrients in latrines. Latrine soils had higher concentrations of nitrogen, carbon, and other nutrients than did nonlatrine soils across all habitats. These inputs corresponded with an increase in plant quality (lower C:N) at latrine sites in plains and canyons, but not in meadows. Stable isotope mixing models suggest that ~7% of nutrients in plains latrines originated from vegetation in meadows, which is disproportionately higher than the relative proportion of meadow habitat (2.6%) in the study area. In contrast, ~68% of nutrients in meadow latrines appear to originate from plains and canyon vegetation, though these habitats made up nearly 98% of the study area. Vicuña diel movements thus appear to concentrate nutrients in latrines within habitats and to drive cross-habitat nutrient subsidies, with disproportionate transport from low-lying, nutrient-rich meadows to more elevated, nutrient-poor plains. When these results are scaled up to the landscape scale, the amount of nitrogen and phosphorus subsidized in soil at plains latrines was of the same order of magnitude as estimates of annual atmospheric nitrogen and phosphorus deposition for this region (albeit far more localized and patchy). Thus, vicuña-mediated nutrient redistribution and deposition appears to be an important process impacting ecosystem functioning in arid Andean environments, on par with other major inputs of nutrients to the system.

Risk effects cascade up to an obligate scavenger.

The effects of predation risk on prey populations have been studied extensively; yet, how risk is manifested in a trophically linked guild-scavengers-has been overlooked. Risk could be particularly consequential for obligate scavengers that are vulnerable while foraging and rely on carrion provisioned by, and shared with, apex predators. We investigated whether Andean condors (Vultur gryphus) respond to predation risk in a landscape where the main source of carrion are camelids killed by pumas (Puma concolor). We hypothesized that condors would exhibit different behavioral responses to predation risk while they search, encounter, and exploit carrion. We explored condor habitat selection while flying by tracking nine birds with satellite transmitters and monitored via camera traps 41 natural carcasses and 25 experimental carrion stations. We found that condors searched for carrion in areas with a high probability of occurrence of puma kills. However, condors avoided exploiting carrion in areas featuring tall vegetation and steep slopes-selected by pumas to stalk prey-suggesting that condors manage risk primarily through the identification of safe foraging sites prior to landing. Our finding that condors avoided foraging near stalking cover for pumas highlights the importance of risk effects beyond predator-prey interactions, particularly for obligate scavengers.

Enteric methane emissions by lactating and dry cows in the high Andes of Peru.

The objective of the study was to determine enteric methane emissions using the sulfur hexafluoride (SF6) technique and comparing with The Intergovernmental Panel on Climate Change (IPCC) methodology in lactating cows (LC) and dry cows (DC) in the Peruvian highlands. Enteric methane (CH4) emissions were measured on 5 LC and 6 DC Brown Swiss in a grazing system without concentrate. Forages samples were collected and analyzed for dry matter, crude protein, and neutral detergent fiber. Milk samples were collected and analyzed for fat, crude protein, and lactose to estimate energy-corrected milk. Animal intakes were measured using the external marker titanium dioxide (production of feces) and crude protein in feces (organic digestibility of the feed) and estimated by using performance data. The enteric methane emissions of LC were higher than methane emissions of DC (325 and 266 g CH4/cow/day for LC and DC, respectively (P < 0.001)). Methane emissions were 358.5 g CH4/day by SF6 technique and 291.6 g CH4/day by IPCC methodology for LC and 337.4 g CH4/day by SF6 technique and 195.8 g CH4/day by IPCC methodology for DC. Methane yields measured by SF6 were higher than methane yields estimated by IPCC methodology (29 g CH4/kg DM and 22 g CH4/kg DM using SF6 technique and IPCC methodology, respectively (P < 0.001)). Methane yields were differently for all expressions by physiological stage and method. The methane conversion factor (Ym) was 9.7% for LC and 9.6% for DC. Methane intensities were similar by method (P > 0.05). It was concluded that IPCC's methodology underestimate the CH4 emissions of dairy systems in the Peruvian Andes; therefore, in order to obtain precise Ym, direct measurements of enteric CH4 in the different regions of Peruvian highlands are required.

Cascading effects of a disease outbreak in a remote protected area.

Disease outbreaks induced by humans increasingly threaten wildlife communities worldwide. Like predators, pathogens can be key top-down forces in ecosystems, initiating trophic cascades that may alter food webs. An outbreak of mange in a remote Andean protected area caused a dramatic population decline in a mammalian herbivore (the vicuña), creating conditions to test the cascading effects of disease on the ecological community. By comparing a suite of ecological measurements to pre-disease baseline records, we demonstrate that mange restructured tightly linked trophic interactions previously driven by a mammalian predator (the puma). Following the mange outbreak, scavenger (Andean condor) occurrence in the ecosystem declined sharply and plant biomass and cover increased dramatically in predation refuges where herbivory was historically concentrated. The evidence shows that a disease-induced trophic cascade, mediated by vicuña density, could supplant the predator-induced trophic cascade, mediated by vicuña behaviour, thereby transforming the Andean ecosystem.

Trace metals and metalloids in Andean flamingos (Phoenicoparrus andinus) and Puna flamingos (P. jamesi) at two wetlands with different risk of exposure in the Bolivian Altiplano.

Birds are widely used as bioindicators in monitoring programs in wetlands. We compare concentrations of seven trace metals and metalloids (TMM) As, Cd, Cu, Fe, Hg, Pb, Znin both feathers and blood in two flamingo species in two high-altitude wetlands in Bolivia, with different levels of anthropogenic point source pollution. Lake Uru Uru (LUU) receives discharges from mining operations, and also effluents from the nearby city of Oruro, while Laguna Colorada (LCo) does not receive contaminants from anthropogenic sources. We sampled water and sediments at each site, as well as flamingos in three age classes in an effort to establish a benchmark for long-term monitoring. Metal concentrations in water did not differ between sites, whereas Zn and Pb concentrations of TMM in sediments were higher at LUU, and Hg higher at LCo. TMM concentrations were highly specific for all separate elements, but results point to differences between Andean flamingo (Phoenicoparrus andinus) chicks and the rest of the classes considered. As flamingo chicks did not molt before sampling, we pose that TMM concentrations in their blood and feathers may respond mainly to local conditions. Eggshells provide additional information, since adults transfer some TMM during egg development. Long-term monitoring in these species should include different age classes and sample both feathers and eggshells to monitor the environmental conditions and bioaccumulation of TMM in these species. Future studies should include sites devoid of natural sources of TMM to help distinguish sources of contamination, since some TMM (As and Pb) may be naturally in high concentrations in remote areas, like Laguna Colorada.

Predictive model of stunting in the Central Andean region of Peru based on socioeconomic and agri-food determinants.

Objectives: A limitation in the design and monitoring of public health policies is the lack of conceptual models to explain their results. The objective of this study was to develop a predictive model of stunting in children under 5 years of age in the central Andean region of Peru, using socioeconomic and agro-productive predictors. Study design: Cross-sectional data of 380 families in 15 districts of the central region of Peru. WHO criteria were used to define stunting prediction model. Methods: An explanatory and predictive study of stunting in children was carried out considering causality criteria through Chi-square tests and bivariate logistic regression. Family food production, maternal education, breastfeeding practices and others determinant related to rural zone conditions were considered as explanatory variables in stunting of children under 5 years old. Three exhaustive models for predicted the presence of stunting was developed. Results: Stunting percentage was 40.3. To Hosmer and Lemeshow test, the best fit was the model that considered the level of maternal education, timely consumption of colostrum, birth weight and guinea pig rearing, having high reliability (P â€‹< â€‹0.05). Conclusions: A predictive model for early detection of stunting risk in rural areas of the Andean region was developed based on simple and easily applied indicators. Effective policies are required to improve the feeding practices of pregnant women, increase breastfeeding and promote guinea pig raising for self-consumption and improve the nutritional status of children.

Divergence in Plant Traits and Increased Modularity Underlie Repeated Transitions Between Low and High Elevations in the Andean Genus Leucheria.

Understanding why some plant lineages move from one climatic region to another is a mayor goal of evolutionary biology. In the southern Andes plant lineages that have migrated along mountain ranges tracking cold-humid climates coexist with lineages that have shifted repeatedly between warm-arid at low elevations and cold habitats at high elevations. Transitions between habitats might be facilitated by the acquisition of common traits favoring a resource-conservative strategy that copes with drought resulting from either low precipitation or extreme cold. Alternatively, transitions might be accompanied by phenotypic divergence and accelerated evolution of plant traits, which in turn may depend on the level of coordination among them. Reduced integration and evolution of traits in modules are expected to increase evolutionary rates of traits, allowing diversification in contrasting climates. To examine these hypotheses, we conducted a comparative study in the herbaceous genus Leucheria. We reconstructed ancestral habitat states using Maximum Likelihood and a previously published phylogeny. We performed a Phylogenetic Principal Components Analysis on traits, and then we tested the relationship between PC axes, habitat and climate using Phylogenetic Generalized Least Squares (PGLS). Finally, we compared the evolutionary rates of traits, and the levels of modularity among the three main Clades of Leucheria. Our results suggest that the genus originated at high elevations and later repeatedly colonized arid-semiarid shrublands and humid-forest at lower elevations. PGLS analysis suggested that transitions between habitats were accompanied by shifts in plant strategies: cold habitats at high elevations favored the evolution of traits related to a conservative-resource strategy (thicker and dissected leaves, with high mass per area, and high biomass allocation to roots), whereas warm-arid habitats at lower elevations favored traits related to an acquisitive-resource strategy. As expected, we detected higher levels of modularity in the clades that switched repeatedly between habitats, but higher modularity was not associated with accelerated rates of trait evolution.

Unique and Potentially Mars-Relevant Flow Regime and Water Sources at a High Andes-Atacama Site.

A field expedition in the High Andes/Atacama Desert region revealed two types of flow-produced structures and a unique flow regime. Gullies somewhat smaller than those on Mars (width: 0.2-1 m, depth: 0.2-0.6 m, length: 4-60 m) were observed as mainly erosional structures. The other flow-related feature called infilled valleys showed activity only in specific, spatially discrete areas during the daytime. The active sections were composed of a source depression where liquid H2O was produced from subsurface buried sources, which flowed down and percolated into fine-grained infilling material of the valley. Several such active sections could be present along one valley, separated by inactive ones. Three types of H2O sources fed them: buried snow, surface snow, and ice left behind from the liquid water that had emerged the preceding day. This latter source has not yet been suggested for Mars. Some aspects related to the formation of the gullies and infilled valleys (H2O budget, albedo, erosional processes) may be similar with the formation processes hypothesized for the recurring slope lineae on Mars. The observed diurnal spatially discrete activity of the infilled valleys is related to the interaction of insolation and mass movement of exhumed subsurface snow, which is also believed to exist on Mars. The Ojos del Salado site is unique in that, despite it being located in the hyperarid High Andes/Atacama Desert region, material from rare snowfall events has been protected due to burial by grains transported by strong winds, supporting ephemeral melting in the long term.

Analog Site Experiment in the High Andes-Atacama Region: Surface Energy Budget Components on Ojos del Salado from Field Measurements and WRF Simulations.

Remote sensing data are abundant, whereas surface in situ verification of atmospheric conditions is rare on Mars. Earth-based analogs could help gain an understanding of soil and atmospheric processes on Mars and refine existing models. In this work, we evaluate the applicability of the Weather Research and Forecasting (WRF) model against measurements from the Mars analog High Andes-Atacama Desert. Validation focuses on the surface conditions and on the surface energy budget. Measurements show that the average daily net radiation, global radiation, and latent heat flux amount to 131, 273, and about 10 W/m2, respectively, indicating extremely dry atmospheric conditions. Dynamically, the effect of topography is also well simulated. One of the main modeling problems is the inaccurate initial soil and surface conditions in the area. Correction of soil moisture based on in situ and satellite soil moisture measurements, as well as the removal of snow coverage, reduced the surface skin temperature root mean square error from 9.8°C to 4.3°C. The model, however, has shortcomings when soil condition modeling is considered. Sensible heat flux estimations are on par with the measurements (daily maxima around 500 W/m2), but surface soil heat flux is greatly overestimated (by 150-500 W/m2). Soil temperature and soil moisture diurnal variations are inconsistent with the measurements, partially due to the lack of water vapor representation in soil calculations.

Geographic distribution analysis of the genusXenodacnis (Birds: Thraupidae) using ecologicalniche modeling

Xenodacnis is a monotypic thraupid genus restricted to the tropical high Andes of Peru and Ecuador. Its only species, X. parina has a large discontinuous distribution from central Ecuador to southern Peru. To date, three subspecies are recognized, all separated by geographical barriers that clouded promote allopatric events. The taxonomic affinities of the Ecuadorian population have not been assessed since its discovery in the 1970s at the Cajas National Park in Azuay province. I studied the environmental affinities between the distribution of the described subspecies and the Ecuadorian population bias ecological niche modeling. I found a distinctive ecological niche in the distribution of each of the analyzed populations and also for the southern Arequipa population. These different environmental niche conditions come apart by deep Andean valleys playing a role as geographical barriers for the isolation of these populations that need further taxonomic analysis.

Xenodacnis es un género de traupido mono típico restringido a los altos Andes tropicales de Perú y Ecuador. Su única especie, X. parina tiene una distribución extensa pero discontinua desde el centro Ecuador hasta el sur de Perú. A la fecha se reconocen tres subespecies, todas separadas por barreras geográficas que pudieron promover eventos alopátricos. Las afinidades taxonómicas de la población de ecuador no se han analizado desde su descubrimiento en los años 70 dentro del Parque Nacional Cajas en la provincia del Azuay. Yo estudié las afinidades ambientales entre las distribuciones de las subespecies descritas y la población en Ecuador mediante modelos de nicho ambiental. Encontré diferentes condiciones ambientales en los nichos de cada una de las poblaciones analizadas y también para la población sureña de Arequipa. Estas diferencias ambientales están separadas por profundos valles Andinos que cumplen el roll de barreras geográficas para el aislamiento de estas poblaciones que necesitan un próximo análisis taxonómico.

A new high-altitude species of centipede from the Andes of Ecuador (Chilopoda, Geophilomorpha, Schendylidae).

Pectiniunguis aequatorialis sp. nov. (Chilopoda: Geophilomorpha: Schendylidae) is described and illustrated on the basis of specimens collected in the Cayambe-Coca Ecological Reserve in the High Andes of Ecuador. The new species is characterized by having ventral pore-fields on the anterior region of the trunk only, a trait that is shared by a single Neotropical congener: Pectiniunguis ascendens Pereira, Minelli Barbieri, 1994 to which it is similar and is compared taxonomically. This is only the second report of a species of the genus Pectiniunguis Bollman, 1889 from mainland Ecuador. The other taxon is Pectiniunguis roigi Pereira, Foddai Minelli, 2001, so far only known from the type locality, Limoncocha (Sucumbíos Province), and herein reported for the first time from Parque Nacional Sumaco Napo-Galeras (Napo Province).

Variaciones espaciales y ontogenéticas en la dieta de un plecóptero de amplia distribución Claudioperla tigrina (Plecoptera: Gripopterygidae) / Spatial and ontogenetic variations in the diet of a widely distributed stonefly Claudioperla tigrina (Plecoptera: Gripopterygidae)

Resumen: La determinación de los hábitos alimentarios permite la comprensión de muchos procesos ecológicos que se dan en los ecosistemas lóticos. El objetivo de este trabajo es: 1) conocer los hábitos alimentarios de ninfas de Claudioperla tigrina en un amplio gradiente altitudinal y latitudinal en Argentina; 2) asignar el grupo funcional trófico (GFT) de C. tigrina; 3) evaluar diferencias entre dietas de los sitios estudiados. Las ninfas estudiadas fueron recolectadas a lo largo de un amplio rango espacial en el noroeste de Argentina e incluyen diferentes estados del desarrollo (cuatro clases de tamaño). El material ingerido fue extraído de la parte anterior del tubo digestivo mediante disección ventral del tórax. Los perfiles dietarios fueron analizados a través de la estimación de parámetros de la distribución multinomial de Dirichlet. Se efectuaron ANOVA's para cada rubro alimentario en función de los sitios. Se utilizó la técnica Multidimensional Scaling (MDS) para identificar los sitios con perfiles alimentarios promedios similares. Se realizó un análisis de amplitud de nicho trófico para evaluar la diversificación de los recursos consumidos en cada sitio. El aparato bucal no muestra variaciones a lo largo del desarrollo ninfal, excepto una mayor esclerotización con la edad. Poseen palpos mandibulares y maxilares relativamente cortos y mandíbulas y maxilas fuertes, esclerozadas y dentadas. Las ninfas ingirieron más de un ítem alimentario, sugiriendo que se trata de una especie flexible en su alimentación. El ítem dominante en la dieta fue la MOPG, los signos de haber sido masticado indican hábitos trituradores. Se encontraron diferencias entre sitios para los ítems MOPF, invertebrados, algas y sedimento, pero no para MOPG. Se obtuvieron las correlaciones para cada eje del análisis MDS. Con el eje 1 se correlacionaron negativamente los sitios AP, LT, LI, C y M (Selva de Yungas y Pastizal de neblina) asociados a un mayor consumo de MOPF, en el lado positivo del eje se encontró el sitio P (Altos Andes) asociado a los ítems invertebrados y sedimento. Para el eje 2 se relacionaron positivamente IN (Pastizal neblina) y LR (Monte de Sierras y Bolsones) con la presencia de algas. Los resultados del análisis de amplitud de nicho revelaron diferencias en el uso de los recursos secundarios de la dieta en los sitios estudiados que puede deberse a la oferta ambiental en las ecorregiones consideradas. El GFT de C. tigrina es triturador/ recolector en Selva de Yungas y Pastizales de Neblina y triturador/ depredador en Altos Andes. La definición del GFT de C. tigrina y el establecimiento de su rol como procesador primario de materia orgánica representa un paso importante para futuros estudios de redes tróficas y otras metodologías basadas en los grupos funcionales.

Abstract: Dietary information gives insight into several ecological processes acting in lotic ecosystems. This work aimed: 1) to identify the dietary habits of Claudioperla tigrina immature stages along a wide altitudinal as well as latitudinal gradient in North Argentina; 2) to define the functional feeding group (FFG) of C. tigrina; 3) to evaluate differences in diet in the studied sites. Studied nymphs were collected from localities widely scattered in Northwestern Argentina and they fell into different developmental stages (four size classes). The ingested material was extracted from the foregut and midgut by using thorax ventral dissection. Dietary profiles were analyzed through the estimation of parameters associated with a Dirichletmultinomial distribution. ANOVA's were performed for each food item using sites as factor. Multidimensional Scaling was used to identify sites with similar dietary profiles. An analysis of food-niche breadth was also performed to evaluate the degree of dietary diversification for the resources consumed in each site. Mouthparts are similar across the different size classes, excepting the increasing sclerotization recorded with age. Mouthparts retained most of the typical chewing groundplan, showing relatively short labial and maxillar palps, and strong, sclerotized and denticulated mandibles and maxillae. Our results pointed out that the nymphs of C. tigrina always ingest two or more food items (CPOM, FPOM, invertebrates and algae), suggesting thus a flexible diet. The diet changed in relation to body size, while finer particles were consumed in the early stages, larger particles were ingested in final stages. Coarse particulate organic matter was the dominant food item, with signals of shredding during ingestion. Differences between sites for FPOM, invertebrates, algae and sediment were detected, but not for MOPG. Correlations were obtained for the first two axis of the MDS analysis. Sites AP, LT, LI, C and M (Yungas Rainforest and Humid Grassland) were negatively correlated with the axis 1 which was associated with increased consumption of FPOM. On the positive side of the axis the site P (High Andes) is associated with a greater proportion of invertebrates and sediment. The sites IN (Humid Grassland) and LR (Argentine Northwest Monte and Thistle of the Prepuna) were located at the positive domain of axis 2 which is in turn associated with a greater count of algae in the dietary contents. We found significant differences in the quantity of secondary items, and this is likely related with the resources environmental availability. The FFG of Claudioperla tigrina is primarily shredder/collector-gatherer in Yungas Rainforest and Humid Grassland shredder/predator in High Andes. FFG classification of C. tigrina and the definition of their role for organic matter processing is an important step for future studies based on functional groups such as analysis of food webs. Rev. Biol. Trop. 65 (3): 1174-1184. Epub 2017 September 01.

Life cycles of dominant mayflies (Ephemeroptera) on a torrent of the high Bolivian Andes / Ciclos de vida de las efímeras (Ephemeroptera) en un torrente de los Andes bolivianos de altura

AbstractThe mayflies of the temperate and cold zones have well-synchronized life cycles, distinct cohorts, short emergence and flight periods. In contrast, aquatic insects from the tropical zones are characterized by multivoltine life cycles, "non-discernible cohorts" and extended flight periods throughout the year. This report is the first observation of life cycle patterns made of two species of mayflies on a torrent in the high elevation Bolivian Andes. The samples were taken from four sites and four periods during a hydrological season. The life cycle of each species was examined using size-class frequency analysis and a monthly modal progression model (von Bertalanffy's model) to infer the life cycle synchrony type. These first observations showed a moderately synchronized univoltine life cycle for Andesiops peruvianus (Ulmer, 1920), whereas Meridialaris tintinnabula Pescador and Peters (1987), had an unsynchronized multivoltine life cycle. These results showed that the generalization of all aquatic insects as unsynchronized multivoltine species in the Andean region may not be entirely accurate since there is still a need to further clarify the life cycle patterns of the wide variety of aquatic insects living in this high elevation tropical environment.

ResumenLos efemerópteros en las zonas templadas y frías, tienen ciclos de vida bien sincronizados, cohortes claras, períodos cortos de emergencia y vuelo. Por el contrario, los insectos aquáticos de las zonas tropicales se caracterizan por ciclos de vida multivoltino, "cohortes no claras" y periodos extendidos de vuelo durante el año. Estas son las primeras observaciones de los patrones del ciclo de vida realizados en dos poblaciones de efemeropteros en un torrente de tierras altas en los Andes de Bolivia. Las muestras se tomaron en cuatro sitios y cuatro periodos durante una temporada hidrológica. El ciclo de vida fue analizado por frecuencia de clases de tallas, y por progresión modal mensual (modelo de von Bertalanffy), con el fin de inferir el tipo de sincronía del ciclo de vida. Estas primeras observaciones mostraron un ciclo de vida univoltino y moderadamente sincronizado para Andesiops peruvianus, mientras que para Meridialaris tintinnabula fue multivoltino desincronizado. Estos resultados muestran que la generalización de todos los insectos acuáticos como especies multivoltina y no sincronizadas en la región andina no puede ser completamente exacta, ya que todavía hay una necesidad de aclarar la definición de los patrones del ciclo de vida de muchos insectos acuáticos que viven en este ambiente tropical de elevada altura.

Placental morphology in two sympatric Andean lizards of the genus Liolaemus (Reptilia: Liolaemidae).

Viviparity is a remarkable feature in squamate sauropsids and it has evolved multiple times in parallel with the formation of a placenta. One example of this repeated evolution of viviparity and placentation occurs in the species-rich South American genus Liolaemus with at least six independent origins of viviparity. However, evolutionary studies of placentation in this genus are limited by a lack of data on placental morphology. The aim of this study is to describe and compare the microanatomy and vessel diameter (Dv, a function of blood flow) of the placenta using scanning electron microscopy (SEM) and confocal laser scanning microscopy (cLSM) in two sympatric Andean viviparous but highly divergent species, Liolaemus robustus and Liolaemus walkeri. We found interspecific differences in cell types in the chorion, allantois, and omphalopleure that may be explained by divergent phylogenetic history. Time elapsed since divergence may also explain the pronounced interspecific differences in vessel diameter, and within each species, there are strong differences in Dv between tissue locations. Both species show features to improve gas exchange in the chorioallantoic placenta including absence of eggshell, large Dv in the allantois (L. robustus) or embryonic side of the uterus (L. walkeri), and when present, microvillous cells in the allantois (L. walkeri). Both species also show features that suggest transfer of nutrients or water in the omphaloplacenta, including an almost complete reduction of the eggshell, secretive material (L. robustus), or vesicles (L. walkeri) on cell surface uterus, and when present specialized cells in the omphalopleure (L. walkeri). No statistical differences in Dv were found among stages 32-39 in each species, suggesting that a different mechanism, other than enhanced blood flow, might satisfy the increased oxygen demand of the developing embryos in the hypoxic environments of the high Andes.

Betacoronavirus 1 in alpacas (Vicugna pacos) in the High Peruvian Andes.

Genetic sequences highly related to Bovine coronavirus (BCoV) were detected in fecal samples from Peruvian 1-3 week old alpaca crias located on six farms in Puno department, some of which shared pastures with cattle. A total of 60 samples were screened for coronavirus using a nested PCR amplification of a fragment of the RNA-dependent RNA polymerase (RdRp) gene. Sequences from 11 positive samples were highly similar to the Kakegawa, Quebec and Mebus BCoV strains (99.5-100.0%) and 99.2% identical to an alpaca Coronavirus (CoV) previously detected in the USA. The detection of genetic sequences related to BCoV from Peruvian alpaca crias suggests possible role of this virus on enteric disorders etiology in the High Andes.

Composición molecular de ácidos húmicos evaluada mediante pirólisis - cromatografía de gases - espectrometría de masas e hidrólisis térmica asistida y metilación en suelos altoandinos de Colombia / Molecular composition of humic acids evaluated by pyrolysis - gas chromatography - mass spectrometry and thermally assisted hydrolysis and methylation in high Colombian Andean soils / Composição molecular de ácidos húmicos avaliada mediante pirólise - cromatografia de gases - massas e hidrólise térmica assistida e metilação, em solos altoandinos em Colômbia

Se determinó la composición molecular de ácidos húmicos (AH), extraídos del horizonte 'A' de suelos altoandinos de Colombia dedicados a tres usos: bosque primario, cultivos y praderas. Los AH se obtuvieron mediante extracción secuencial de la materia orgánica humificada (MOH) con soluciones de tetraborato, pirofosfato e hidróxido de sodio (0,1N), y fueron purificados mediante diferentes procesos analíticos. Su composición molecular se determinó a través de Py-GC/MS y THMA. Los diferentes productos de la pirólisis se clasificaron atendiendo a la familia química a la que pertenecen; prevalecieron los ácidos grasos (FA) como el producto más abundante en los AH de todos los usos, mientras que los fenoles, esteroles, S-compuestos y terpenos se encontraron en menor abundancia. Se presentaron diferencias en los porcentajes de abundancia relativa de los grupos identificados, demostrando así que el cambio de uso de suelo influye en sus propiedades físicas, químicas y biológicas, por lo que se perciben diferentes grados de transformación que afectan la composición de los AH y su reactividad en el suelo.

It was determined the molecular composition of humic acids (HA) extracted from 'A' horizon in Colombian high Andean soils dedicated to three uses: primary forest, croplands and pastures. The AH were obtained by sequential extraction of humified organic matter (HOM) with tetraborate, pyrophosphate and sodium hydroxide (0.1N) solutions; HA were purified through various analytical processes. Its chemical composition was determined by Py-GC/MS and THMA. Different pyrolysis products were classified in response to the chemical family to which they belong, prevailed fatty acids (FA) as the most abundant in all AH, while phenols, sterols, terpenes and S-compounds were found in lower abundance. There were differences in the percentages of relative abundance of the identified groups, showing that the land use change influences the physical, chemical, and biological propertiers of soils that are perceived at different levels of transformation, affecting the HA composition and its reactivity in the soil.

Foi determinada a composição molecular de ácidos húmicos (AH), extraídos do horizonte 'A' dos solos altoandinos, Colômbia, surgiro a três usos: floresta primária, cultivo e pastagem. Os AH se obtiveram através de extração sequencial da Matéria Orgânica Humificada (MOH) com soluções de tetraborato, pirofosfato e hidróxido de sódio (0,1N), e foram purificados por diversos processos analíticos. A sua composição química foi determinada por Py-GC/MS e THMA. Os diferentes produtos da pirolise foram classificados atendendo à família química à que pertencem, prevaleceram os ácidos gordurosos (FA) como o produto mais abundante em todos os AH, enquanto os fenóis, esteróis, S-compostos e terpenos foram encontrados em menor abundância. Surgiram diferenças nas percentagens da abundância relativa dos grupos identificados, mostrando que a mudança de uso de solo influencia nas propriedades físicas, químicas e biológicas do solo podendo ser perceptíveis diferentes graus de transformação, que afetam a composição dos AH e sua reatividade no solo.