Repositorio Digital Ikiam (Univ. Regional Amazónica)
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Salt lick characterization and their relation with visiting fauna in Amazonia
Get PDFSalt licks are key areas the forests, where a great diversity of mammals and birds frequently
visit them to consume clay. Some hypotheses have been proposed to explain this geophagic
behaviour, mineral supply and detoxify are the two more studied. However, the principal
reasons that explain soil consumption at salt licks remains unclear. The aim of this study is
the physic - chemical characterization of salt licks with different levels of intervention and
to asses, their relation with fauna visits. During dry season, from October 24 to December
8 in 2019, 13 salt licks was select at Yasuní National Park. Na, K, Ca and Mg concentration
was determined, by ion chromatography with a high-capacity cation-exchange column
(HPLC). Visits of fauna for each salt lick was also recorded using camera traps with a total
sample effort of 256 trap/nights (with a mean of 25 trap/nights per salt lick). A total of 13
mammals and 10 birds species associated to salt licks was recorded. Na concentrations
were typically higher at all salt licks samples in contrast with control sites. Using guidance
models a great influence was observed from number of predation events and disturbance
level on the frequency of animals visit to salt licks. High Na concentrations appears to be
more associated to ungulates visits as Tapirus terrestris and Tayassu pecari, both with
Mazama americana and Ara macao were frequently recorded species (with visit rates
higher than 11%). Although high Na concentration at salt licks, soil chemical composition is
not the only factor that determine visit frequency, therefore it is necessary to link
multidisciplinary research that includes ecological and geochemical approaches. These
results are relevant to understand the role of salt licks and the influence of environment
on the species that visit them, being important information for conservation programs at
landscape level or areas of high conservation priority such as Yasuní National Park
Microclimate buffering and thermal tolerance across elevations in a tropical butterfly
Get PDFMicroclimatic variability in tropical forests plays a key role in shaping species distributions and their ability to cope with environmental change, especially for ectotherms. Nonetheless, currently available climatic datasets lack data from the forest interior and, furthermore, our knowledge of thermal tolerance among tropical ectotherms is limited. We therefore studied natural variation in the microclimate experienced by tropical butterflies in the genus Heliconius across their Andean range in a single year. We found that the forest strongly buffers temperature and humidity in the understorey, especially in the lowlands, where temperatures are more extreme. There were systematic differences between our yearly records and macroclimate databases (WorldClim2), with lower interpolated minimum temperatures and maximum temperatures higher than expected. We then assessed thermal tolerance of 10 Heliconius butterfly species in the wild and found that populations at high elevations had significantly lower heat tolerance than those at lower elevations. However, when we reared populations of the widespread H. erato from high and low elevations in a common-garden environment, the difference in heat tolerance across elevations was reduced, indicating plasticity in this trait. Microclimate buffering is not currently captured in publicly available datasets, but could be crucial for enabling upland shifting of species sensitive to heat such as highland Heliconius. Plasticity in thermal tolerance may alleviate the effects of global warming on some widespread ectotherm species, but more research is needed to understand the long-term consequences of plasticity on populations and species
RGCxGC toolbox: An R-package for data processing in comprehensive two-dimensional gas chromatography-mass spectrometry
Get PDFComprehensive two-dimensional gas chromatography (GC×GC) offers detailed chemical information about
volatile and semivolatile analytes from complex samples. However, the high complexity of the data structure
encourages the development of new tools for a more efficient data handling and analysis. Although some tools have already been presented to overcome this challenge, there is still need for improvement. In this manuscript, we present a toolbox containing a pipeline for end-to-end basic GC×GC data processing which can be used for both, signal pre-processing and multivariate data analysis. The pre-processing algorithms perform signal smoothing, baseline correction, and peak alignment, while the multivariate analysis is done through Multiway
Principal Component Analysis (MPCA). The software is capable to prepare the chromatographic data for further applications with other chemometric tools, e.g.: cluster analysis, regression, discriminant analysis, etc. The performance of this new software was tested on in-house experimental dataset and on two other published datasets
Spatial and temporal variation of forest net primary productivity components on contrasting soils in northwestern Amazon.
Get PDFClimate is a strong determinant of tropical forest productivity; therefore, it is often assumed
that Amazonian forest growing on the same local rainfall regime responds similarly to fluctuations in rainfall,
independently of soil differences among them. We evaluated intra- and inter-annual variation of net
primary productivity (NPP) components, and forest dynamics during 2004–2012 yr in five forests on clay,
clay-loam, sandy-clay-loam, sandy-loam and loamy-sand soils, and the same local rainfall regime in northwestern
Amazonia (Colombia). The questions were as follows: (1) Do NPP components and forest dynamics
respond synchronously to temporal rainfall fluctuations? (2) Are the responses between above and
belowground components and forest dynamics similar for different forest stands? A slight and complex
synchronicity among different NPP components in their response to temporal rainfall fluctuations were
found; few plots showed that aboveground biomass (AGB) and stem growth were susceptible to rainfall
fluctuations, while belowground components (fine roots) showed correlation with one-month lagged rainfall.
Furthermore, despite that northwestern Amazonia is considered relatively aseasonal, litterfall showed
high seasonality in the loam-soil forest group, as well as the fine-root mass, particularly during the 2005
drought. Litterfall correlation with rainfall of sandy-loam terra-firme forest was time lagged as well as
fine-root mass of the loamy-sand forest. The correlation between mortality and rainfall was weak, except
for the loamy-sand forest (white-sand forest, 77%). High mortality rates occurred in the non-flooded forests
for the censuses that included the dry years (2004–2005, 2005–2006). Interestingly, litterfall, AGB increment,
and recruitment showed high correlation among forests, particularly within the loam-soil forest group.
Nonetheless, leaf area index (LAI) measured in the most contrasting forests (clay and loamy-sand soil) was
poorly correlated with rainfall, but highly correlated among them, which could be indicating a phenotypic
response to the incident radiation in these sites; also, LAI did not reflect the differences in NPP components
and their response to rainfall. Overall, the different temporal behavior of NPP components among forests
in relation to rainfall fluctuations suggests the important role that soil exerts on the responses of plant species
in each site, besides their effect on forest dynamics and community composition
Una breve introducción a los modelos de nicho ecológico
Get PDFa degradación y transformación de los ecosistemas. Hasta hace poco, la disponibilidad de mapas de alta resolución para mostrar los patrones de biodiversidad era limitada. Sin embargo, ahora existen los desarrollos conceptuales, herramientas, métodos y numerosas bases de datos accesibles para estudiar y entender de manera más eficiente los patrones de biodiversidad a diversas escalas espacio-temporales. En este capítulo se presentan conceptos básicos y se mencionan algunas herramientas disponibles para analizar la biodiversidad de manera espacialmente explícita mediante la creación de mapas y modelos; asimismo, se presentan algunos ejemplos de la manera en que se han utilizado estos mapas para analizar espacialmente la biodiversidad
Biogas based polygeneration plant options utilizing dairy farms waste: A Bolivian case
Get PDFThis study presents a comparative techno-economic feasibility analysis for two polygeneration plant solutions, applied to low-income dairy farms in Bolivia. The first option considers an internally fired microturbine (IFMT) and, the second, an internal combustion engine (ICE). They are integrated with an absorption refrigeration system and a fertilizer dryer. Biogas, produced with farms waste, fuels these power generators. The levelized costs of biogas for cooking, electricity, cooling and fertilizers were determined. The cost of biogas, for both options, was found to be 0.020 USD/kWh, which is lower than the subsidized price of LPG. The most competitive cost of electricity was determined for the ICE plant option; it was found to be 0.082 USD/kWh and is lower than the subsidized cost of fossil fuel-based electricity. The cost of cooling was found to be around 0.082 USD/kWh, which is slightly higher than the cost of cooling supplied by using grid electricity. In a realistic scenario, the shorter payback period was found to be 4.4 years for the ICE plant option. From this, the ICE-based plant was found as the most feasible option. Additionally, if no subsidies are applied to the fossil fuel-based services, the proposed polygeneration systems are a highly competitive alternative
Cruzioseptins, antibacterial peptides from Cruziohyla calcarifer skin, as promising leishmanicidal agents
Get PDFScreenings of natural products have significantly contributed to the discovery of novel leishmanicidal agents. In this study, three known cruzioseptins—antibacterial peptides from Cruziohyla calcarifer skin—were synthesized and evaluated against promastigotes and amastigotes stages of Leishmania (L.) amazonensis and L. (V.) braziliensis. EC50 ranged from 9.17 to 74.82 μM, being cruzioseptin-1 the most active and selective compound, with selectivity index > 10 for both promastigotes and amastigotes of L. (V.) braziliensis. In vitro infections incubated with cruzioseptins at 50 μM showed up to ∼86% reduction in the amastigote number. Cruzioseptins were able to destabilize the parasite's cell membrane, allowing the incorporation of a DNA-fluorescent dye. Our data also demonstrated that hydrophobicity and charge appear to be advantageous features for enhancing parasiticidal activity. Antimicrobial cruzioseptins are suitable candidates and alternative molecules that deserve further in vivo investigation focusing on the development of novel antileishmanial therapies
Tratamiento de aguas residuales de piscicultura con fines de reutilización y análisis de mecanismos de bloqueo de poro
Get PDFEn el escenario climático actual resulta importante explorar afluentes de agua no
convencionales para mantener la seguridad hídrica; este es el caso de los afluentes de
origen acuícola. Una de las tecnologías más utilizadas para la producción de agua potable
es la Ultrafiltración. A pesar de su amplio uso, el principal inconveniente de esta tecnología
es el taponamiento de membranas. Con el fin de tener un mayor entendimiento de los
procesos de taponamiento se han desarrollado múltiples modelos para caracterizar el
fouling de membrana. El presente estudio evalúa el proceso de ultrafiltración de afluentes
de origen piscícola y utiliza los modelos estructurales y de taponamiento de poro para
obtener información de la estructura taponante formada durante el tratamiento. Muestras
de agua usadas para la producción de peces fueron colectadas y filtradas a través de
membranas de ultrafiltración, analizando parámetros fisicoquímicos, microbiológicos,
moleculares y asociados al proceso de ultrafiltración. Los resultados muestran que la
ultrafiltración de afluentes con altas cargas de contaminantes forma estructuras
taponantes más altas y más porosas respecto a las estructuras formadas por afluentes
menos contaminados. A partir de estos resultados se propone un modelo conceptual de
taponamiento de membrana por etapas. En cada una de las etapas ocurren interacciones
membrana-taponante y taponante-taponante. Se sugiere en investigaciones futuras
realizar exploraciones con el análisis de un mayor número de contaminantes, la
comparación de los resultados experimentales obtenidos con modelos de contaminantes
y explorar con mayor profundidad las poblaciones microbianas asociadas a este proces
Diversity patterns of aquatic macroinvertebrates in a tropical high-Andean catchment
Get PDFGlacierised catchments are remote and hostile environments, in which streams
from different water sources (e.g., glacier melt, rain/snowmelt, groundwater) converge, creating a complex
mosaic of stream sites with varying levels of glacial influence and environmental conditions. This environmental
heterogeneity, in turn, influences the assemblage and composition of aquatic communities and produces complex
patterns of species diversity at the catchment scale. Objectives: In this contribution, we assessed biodiversity
and community composition of aquatic macroinvertebrate communities from 51 stream site types in a glacierised
catchment in the tropical Andes. The aim of our study was to: (1) determine diversity, rarity, commonness and
spatial distribution patterns of aquatic macroinvertebrate communities from sites with different water sources,
and (2) identify which environmental variables influence the density and presence of macroinvertebrate taxa
and, in particular, of the subfamilies of the ubiquitous chironomids. Methods: Our study sites were grouped
according to their water source and to their percentage of glacier coverage in the catchment (GCC). At each
site we sampled aquatic macroinvertebrates, measured environmental variables and assessed community differences
and environmental influence with ordination analyses and generalized linear models. Results: Kryal
and mixed sites had an important proportion of rare taxa. Mean richness was highest in the mixed sites and
lowest in the sites with the highest glacier cover; while sites with an intermediate percentage of glacier cover,
had the highest values of α and β diversity. We found that 13 taxa (15.9%) were common to all stream site
types. SIMPER analysis showed that Orthocladiinae, Hyalella sp. and Andesiops sp. contributed the most to
the dissimilarity between site types (˃ 45% of cumulative contribution). RDA showed that kryal sites were
associated with high turbidity and density of Podonomids, and with low temperature, amount of CPOM and
densities of both Anomalocosmoecus sp. and Andesiops sp. Orthocladinae was associated with high current
velocity and chlorophyll a concentration, whereas Hyalella sp. had a positive relationship with higher pH and
streambed stability. Generalized linear models showed that GCC was the main variable explaining all faunal
metrics. Current velocity explained macroinvertebrate abundance, water temperature was related to chironomid
density and chlorophyll a influenced Orthocladiinae presence-absence. Conclusions: Our results suggest that by
favoring the presence of rare taxa and taxa turnover, glacier influence may increase biodiversity in glacierised catchments. In terms of biodiversity conservation, this study confirms an urgent need to increase knowledge of
high-Andean stream biodiversity, especially in highly heterogenous glacierised catchments, to better describe
regional biodiversity patterns and community composition of these highly vulnerable freshwater ecosystems.
Detailed analyses of benthic communities and development of databases are key for conservation strategies.
Water management municipalities and/or enterprises should consider water quality and stream types for more
sustainable management of these important ecosystems
Thraulodes marreroi Chacón, Segnini y Domínguez (Ephemeroptera: Leptophlebiidae: Atalophlebiinae): nuevos registros para Venezuela y un análisis sobre su distribución neotropical mediante el modelo de nicho ecológico
Get PDFSe registran nuevas localidades para Thraulodes marreroi en Venezuela y se analiza su potencial distribución geográfica en el Neotrópico mediante el modelo de nicho ecológico, utilizando el algoritmo de Máxima Entropía (MaxEnt), con base en los reportes de Brasil, Panamá y Venezuela. Se incluyen descripciones sobre el hábitat lótico y las subregiones fitogeográficas o unidades de paisaje a través de las cuales discurren las quebradas donde se recolectaron los adultos: los Llanos Occidentales y la Cordillera de la Costa Central. Thraulodes marreroi parece ser una especie característica de ríos y quebradas que drenan a través de sistemas boscosos, desde bosques semi-deciduos y deciduos hasta tropicales lluviosos amazónicos, a altitudes que no sobrepasan los 300 msnm. Es la única especie del género, con posible especiación en el Neotrópico suramericano, que ha sido registrada en el Neotrópico mesoamericano (Panamá). Antes del registro en Panamá, solo el Neártico y el Neotrópico mesoamericano compartían especies de Thraulodes. Finalmente se consideró oportuno actualizar la lista de especies de Thraulodes para el continente americano