Search Results (43)

Background/Objectives: Vector-borne diseases (VBDs) remain a major global public health challenge, particularly in tropical and subtropical regions. In eastern Colombia, the department of Meta reports a high incidence of arboviral infections such as dengue, as well as parasitic diseases including malaria and leishmaniasis. This study aimed to conduct baseline entomological surveillance and molecular screening of Diptera vectors to detect the circulation of arboviruses and parasitic pathogens in two municipalities of Meta, Fuente de Oro and Vista Hermosa. Methods: Adult mosquitoes and sand flies were collected in both municipalities and identified primarily at the genus level, with Anopheles specimens identified to species level. A total of 790 insects were collected, of which 780 were processed in 148 pools and 10 were analyzed individually. Molecular detection of pathogens was performed using PCR and RT-PCR to screen for dengue virus (DENV) serotypes, Zika virus (ZIKV), Chikungunya virus (CHIKV), Oropouche virus (OROV), Plasmodium spp., and Leishmania spp. Results: DENV was detected in 34.8% (55/158) of the processed pools, with DENV-1 identified as the most prevalent serotype. Culex was the most abundant genus overall, particularly in Fuente de Oro, while Aedes predominated in Vista Hermosa. MIR estimates indicated higher molecular detection likelihood in Aedes compared with Culex. Plasmodium vivax and P. falciparum were detected in pools of Anopheles darlingi and Anopheles rangeli, respectively. No molecular evidence of Leishmania DNA was detected in Lutzomyia specimens, and no positive detections were observed for ZIKV, CHIKV, or OROV. Conclusions: The molecular detection of DENV and Plasmodium spp. in field-collected vectors provides valuable baseline evidence of pathogen circulation in Meta, Colombia. While the findings do not imply vector competence, they highlight the importance of sustained entomological surveillance to inform integrated vector control strategies and guide future studies incorporating species-level identification and longitudinal sampling in endemic regions. Full article

Vegetation spatial heterogeneity is fundamental to biodiversity management and ecosystem service provision, yet detailed phytosociological mapping of forest vegetation remains largely unresolved in the Colombian Orinoquia. This study characterized the geographic distribution of forest vegetation through the integration of 178 field surveys, environmental complex variables defined by geomorphological and bioclimatic gradients, and multi-sensor satellite imagery combining Landsat-8 optical bands and Sentinel-1 dual-polarization data, processed within a Random Forest classification framework in Google Earth Engine. Classifications achieved overall accuracies between 0.910 and 0.975 and Kappa coefficients above 0.93, identifying 24 phytosociological alliances or geobotanical formations distributed across approximately 7,565,696 ha, representing 34.63% of the region. Forest cover ranges from 10.95% in the Floodplain to 55.22% in La Macarena, with the High Plain concentrating the greatest formation diversity. The spatial organization of forest vegetation is primarily governed by the geomorphological gradient—fluvial, denudational, and structural—and limiting bioclimatic factors, together with their associated edaphic−hydrological regimes, with anthropic transformation driven by cattle ranching and agricultural expansion constituting the principal threat to forest cover. These results advance beyond existing land cover surrogates, providing an empirically validated cartographic framework for biodiversity assessment, habitat modeling, and natural capital management in the Colombian Orinoquia. Full article

Soil organic carbon (SOC) stocks in cacao agroecosystems are characterized by accumulating large amounts. They depend on the balance between organic matter inputs (plant residues, roots) and losses (decomposition, erosion), being closely related to climatic conditions, soil nature, vegetation type, topography, and land management practices. The objective of this study was to quantify SOC stocks (0–30 cm) and assess key soil fertility indicators across 107 georeferenced sampling locations in cacao production systems of Guamal (Meta, Colombian Llanos Piedmont). Soil pH varies between extremely acidic and moderately acidic (3.8–6.0; mean 4.57), while available P (Bray II) and exchangeable bases showed low concentrations. Organic carbon concentration averaged 1.18% and bulk density averaged 1.17 g cm⁻³. SOC stocks averaged 41.10 Mg C ha⁻¹, ranging from 7.49 to 81.55 Mg C ha⁻¹, evidencing marked spatial contrasts in carbon storage. Spearman correlations highlighted coupled soil chemical controls, including positive associations of pH with Ca²⁺ and P availability and strong negative associations of pH and P with exchangeable Al³⁺, consistent with acidity-driven fertility constraints. Principal component analysis (PCA) further identified a dominant fertility gradient structured by pH, P availability, and Ca²⁺, and a second axis related to organic carbon and cation retention. Spatial modeling using inverse distance weighting (IDW) in ArcGIS supported the visualization of SOC stock variability across the study area. Overall, the results indicate that SOC stocks in these predominantly sandy soils are strongly influenced by acidity-related constraints and heterogeneous nutrient status, underscoring the need for site-specific management to jointly enhance soil fertility and climate-mitigation potential in cacao systems. Therefore, it would be advisable in the future to address the study of differential variations in soil C storage related to chemical fertilizer application rates, especially in the long term. Full article

This study presents a high-resolution mapping of grassland phytosociological alliances in the Colombian Orinoquia by integrating multi-source remote sensing data (Landsat-8 optical and Sentinel-1 SAR) with environmental variables within a Random Forest classification framework. Based on 292 rigorously classified vegetation plots, we modeled the distribution of 18 alliances across dominant geomorphological units: the alluvial plain (north) and the high plain (south-central). Results demonstrate that natural vegetation covers 73.74% of the region, with grasslands (41.55%) representing a more extensive formation than forests (32.19%). The alliances Paspalo pectinati–Axonopodion aurei (6.02%) and Axonopodo aurei–Trachypogonion spicati (4.37%) were identified as the most widespread. Ecological analysis revealed a pronounced dominance of C₄ Poaceae species, particularly in alliances such as Sipaneo pratensis–Axonopodion purpusi (60% C₄ diagnostic species), reflecting adaptations to seasonal moisture stress and high irradiance. Our methodology demonstrates that coupling phytosociological field data with multi-sensor remote sensing achieves high classification accuracy (79–87%), providing a robust tool for moving beyond descriptive vegetation mapping toward a comprehensive understanding of grassland distribution patterns at regional scales. Full article

The Colombian Orinoquia was shaped within a tectonic and sedimentary framework linked to the uplift of the Andean cordilleras during the Oligocene–Miocene. This orogenic event generated two tectonic fronts and facilitated extensive fluvial sedimentation across a broad alluvial geosyncline. The present geomorphological configuration reflects the cumulative interaction of tectonic and erosional processes with Quaternary climatic dynamics, which together produced complex landscape assemblages characterized by plains with distinctive drainage patterns. To delineate and characterize geomorphological units, we employed multidimensional imagery and Machine Learning techniques within the Google Earth Engine platform. The classification model integrated dual polarizations of synthetic aperture radar (L-band) with key topographic variables including elevation, slope, aspect, convexity, and roughness. The analysis identified three major physiographic units: (i) the Foothills and the Floodplain, both dominated by fluvial environments; (ii) the High plains and Serranía de La Macarena (Macarena Mountain Range), where denudational processes predominate; and (iii) localized aeolian environments embedded within the Floodplain. These contrasting dynamics have generated a broad spectrum of landforms, ranging from terraces and alluvial fans in the Foothills to hills and other erosional features in La Macarena. The Floodplain, developed over a sedimentary depression, illustrates the combined action of fluvial and aeolian processes, whereas the High plains is characterized by rolling plains and peneplains formed through the uplift and erosion of Tertiary sediments. Such geomorphic heterogeneity underscores the interplay between tectonic activity, climatic forcing, and surface processes in shaping the Orinoquia landscape. The geomorphological classification using Random Forest demonstrated high effectiveness in discriminating units at a regional scale, with accuracy levels supported by confusion matrices and associated Kappa indices. Nevertheless, some degree of classificatory overlap was observed in fluvial environments, likely reflecting their transitional nature and complex sedimentary dynamics. Overall, this methodological approach enhances the objectivity of geomorphological analysis and establishes a replicable framework for assessing landform distribution in tropical sedimentary basins. Full article

Influenza A virus (IAV) poses a significant threat to animal and public health due to its wide host range and potential for interspecies transmission. This study aimed to conduct a comprehensive survey of IAV in a wide range of wildlife in the Orinoco flooded savannas of Colombia, a region of high biodiversity and a strategic location for monitoring viral transmission. Sampling was conducted during both dry and rainy seasons in two localities. ELISA and qPCR targeted 2028 individuals from 173 bird, mammal, and reptile species, 124 of them without previously published reports. There were positive results for 54 species, with 34 representing first-time world reports. Of the qPCR, 13.4% were positive from birds, and 2.9% were from mammals. Seropositivity was identified in 5.7% of birds, 2.7% of mammals, and 1.3% of reptiles. These findings underscore the potential role of these diverse species as reservoirs or incidental hosts in the transmission cycle of IAV, emphasizing the need for expanded research on less-studied taxa and their ecological interactions. The results also contribute to our understanding of the epidemiology of IAV in the Neotropics and can inform future surveillance and mitigation strategies. Full article

Ticks are arthropods responsible for transmitting microorganisms important to wild, domestic, and human animals. In ecosystems where they are distributed, interactions between hosts are a constant risk. This study analyzed voluntary case reports of tick infestations in humans and tick collections from wild and domestic animals in six different locations in the flooded savanna region of the Colombian Orinoquia. Classical and molecular taxonomy were used to identify tick species. Individuals infested with ticks were monitored for clinical manifestations related to tick bites. A total of 22 ticks were found infesting five men and one woman, aged between 9 and 60 years. Both classical and molecular taxonomy confirmed that 100% of the ticks infesting humans and animals were Amblyomma mixtum. Two of the six individuals reported primary and secondary skin reactions during and after the tick bite, including mild-to-severe inflammatory reactions, pruritus, and erythematous papules that persisted up to 72 h. This study provides, for the first time, compiled information on clinical skin manifestations caused by A. mixtum in humans in the flooded savanna region and in Colombia as a whole. These findings serve as a theoretical basis for developing surveillance programs targeting infestations caused by this arthropod. Full article

This study assesses the current status of selected soil properties of an expanding equatorial agricultural region (Arauca, Colombia) across six landscapes, with the final focus being on evaluating overall soil quality. Field surveys, morphological descriptions, and laboratory analyses of 133 soil profiles were investigated. The landscapes include mountains (25 profiles), foothills (17), hills (11), alluvial plains (43), alluvial plains with dunes (21), and alluvial valleys (16). Soils are classified into six Reference Soil Groups (WRB FAO): Gleysols, Acrisols, Arenosols, Ferralsols, Leptosols, and Cambisols. The findings indicate high acidity, low fertility, and deficient exchangeable bases. Indeed, pH ranges from extremely acid to slightly acid (3.5–6.4), and exchangeable acidity saturation percentage (%SAI) values reach 100% in some areas. Soil textures vary from clay loam to sandy loam and clay. Nutrient contents are ranked in the order Cambisols > Gleysols > Arenosols > Ferralsols > Acrisols > Leptosols. Correlation analysis reveals that clay content positively influences the exchangeable basis percentage, while organic matter (OM) negatively correlates with the nutrients phosphorus, calcium, and magnesium. This study highlights that landscape position influences soil quality, with lower landscape positions having better quality than upper ones. These results provide insights into soil fertility and nutrient availability, which helps to predict suitable plant cultivation areas when increasing areas for agricultural use versus forestry in Arauca. The inclusion or maintenance of diverse tree species is a key element in maintaining the production of organic matter and, consequently, generating better soil quality. Full article

The Orinoquía region of Colombia includes diverse ecosystems such as riparian forests and seasonal savannas, which play vital roles as biodiversity reservoirs. However, increased fire activity, driven by both natural and anthropogenic pressures, poses mounting threats to these ecosystems. Despite their importance, the effects of fire on faunal communities, especially in transitional habitats, are not well understood. Understanding biodiversity responses to fire across different recovery stages is essential for conservation planning. This study aimed to assess the effects of fire occurrence and recovery time on dung beetle communities as an indicator of ecosystem resilience. We analyzed taxonomic responses—including species richness, abundance, and Hill diversity indices (D₀, D₁, D₂)—as well as functional traits such as guild richness, biomass, and food relocation behavior, across riparian forest–savanna ecotones under varying fire histories. Our results indicate that recent fires (≤1 year) and high fire frequencies (4–5 events) negatively affect species diversity and abundance. Dominance by a few disturbance-tolerant species, such as Digitonthophagus gazella, was observed in burned savannas, while forest habitats supported both rare and dominant taxa. Despite taxonomic declines, functional redundancy was maintained, largely due to the prevalence of small-bodied species. However, we observed a general resilience effect in which core species contributed to postfire community reassembly. Functional redundancy was maintained, with small dung beetles dominating the biomass and guild composition. The conservation status of transitional habitats, particularly the forest–savanna ecotone, played a critical role in postfire dung beetle community restructuring. The presence of resilient assemblages highlights the importance of dung beetles in sustaining key ecosystem functions following fire events. These findings underscore the potential of dung beetles as bioindicators for postfire monitoring and emphasize the need for improved fire management strategies in sensitive ecosystems. Full article

The evolutionary history of the Caribbean candelabrum octocorals from the genus Eunicea (Plexauridae: Octocorallia) remains unknown despite their high diversity and abundance in reef environments. Understanding the evolutionary relationships between and within the Eunicea species is critical to accurately measuring the group diversity. Furthermore, this group has a high potential for cryptic diversity and new species, particularly given the rich morphological variability. Conventional molecular markers, however, have not provided a precise positioning for the species inside the genus. Here, we provide the first phylogenomic reconstruction of these candelabrum octocorals employing NextRAD, a reduced-representation sequencing technique, to generate thousands of SNPs. We include 15 morphospecies sampled between valid and new species throughout the Caribbean. At large, the phylogeny is well supported and resolved. In total, 13 species-level clades are discernible, including two lineages with demonstrated genetic and morphological variation that are considered and described as two new species, Eunicea criptica sp. nov. and E. colombiensis sp. nov., both previously assigned as E. clavigera and the second as the “thick morphotype”, thereby increasing the diversity of the group. Understanding the magnitude of species diversity within Eunicea is essential for directing conservation initiatives and clarifying the biological processes in reef ecosystems. Full article

The Colombian Orinoquia is considered one of the eight most important ecosystems in the world. Savannah ecosystems play an essential role in providing ecosystem services. The objectives were (a) to explore and identify the perceptions of traditional farmers and institutional representatives regarding human well-being, animal welfare and the environment, and (b) to identify environmental challenges and opportunities for improvement based on the “One Welfare” concept. Three focal groups were developed: male and female farmers and institutional representatives (n = 24) from Vichada. A thematic analysis, coding with an inductive approach and the definition of themes and sub-themes were carried out. The concept of being “a good farmer” explains the behavior of the producers, where the perception of human well-being is associated with the value of the family and the sense of pride in their tradition as “llanero”. Animal welfare was considered a symbol of profitability and prestige for cattle farmers, a concept that, for them, mixed traditional management, water supply, shade and feed, good health and the natural behavior of cattle. Regarding the environment, this concept is based on their awareness of the importance of conserving the natural savannah. Among the environmental challenges described are climate change, solid waste management and the use of controlled burns. Regarding opportunities for improvement, they proposed strengthening institutional dynamics, partnerships, environmental governance and education. Our results can provide information on the “One Welfare” approach and the motivation of farmers to care for animals and the environment, a fundamental aspect for developing effective intervention strategies. Full article

The relationships between environmental characteristics and species richness in the grasslands of the Colombian Orinoquia are presented and analyzed using an ordinal logistic regression model. Ordinal and scale covariates were included, and their bivariate significance was assessed using Spearman’s rho and Kendall’s Tau-b. The covariates that showed statistical significance with the weighted richness thresholds (WRT) and defined the model were the soil depth and the soil moisture regime, both of which had positive correlations. In contrast, the percentage of bare soil and the monthly minimum temperature showed negative correlations. This contribution highlights the relevance of articulating and combining the floristic and phytosociological characterization of grassland vegetation to advance the predictive studies aimed at defining and understanding the potential divergent relationships between the vegetation and the basic attributes of the natural environment, along with their implications for conservation. Full article

Rainwater harvesting is a popular artisanal method that provides substantial economic advantages and effectively addresses the issue of water scarcity in many parts of Colombia. This method may not be appropriate from a public health standpoint in every instance. Despite Colombia’s ample precipitation, ensuring a stable water supply is problematic, particularly due to the dramatic fluctuations in weather patterns, such as droughts and severe rainy seasons, which affect the dependability of the water delivery system. This study examines the urban region of Villavicencio with two main objectives: (I) to assess the physico-chemical and microbiological quality of rainwater in the municipality’s residential and commercial sectors; and (II) to analyze the spatial distribution of physico-chemical parameters within the study area. The quality and spatial distribution of rainwater resources in the urban catchment region of Villavicencio were evaluated through the analysis of data obtained from several sampling locations. Full article

The native grasses of the flooded savannah ecosystem are produced under natural conditions and there is little information on the productive and nutritional response to the application of fertilizers. They are proposed as a strategy for adaptation to climate change and for the sustainable development of livestock farming. The aim of the study was to evaluate the response to low doses of fertilization of native grasses (“bank” grasses: Paspalum plicatulum, Panicum versicolor, and Paspalum sp. “Low” grasses: Leersia hexandra and Hymenachne amplexicaulis) in flooded savannah conditions. The green forage samples were taken in a 1 m² frame at 28-, 35-, and 42-day cutting intervals and biomass production was estimated with and without fertilization. After 35 days, the nutritional composition was analyzed by near-infrared reflectance spectroscopy (NIRS). The effect of fertilization and the grasses × cutting interval interaction influenced (p < 0.05) green forage (GF, t/ha) and dry matter (DM, t/ha). The effect of fertilization and the grasses × fertilization interaction on the nutritional composition only influenced the content of calcium (Ca²⁺) and magnesium (Mg²⁺) in the “low” grasses, while in the “bank” grasses, it influenced the sodium (Na) content (p < 0.05). The application of fertilizers generated significant differences in forage yield, but not in the general nutritional composition of grasses. However, some numerical variations were observed in favor of fertilized grasses. According to these results, the application of fertilizers will not be required to increase the value of the nutritional composition. Native grasses constitute an important sustainable food resource for livestock in flooded savannah ecosystems. This study constitutes the first approximation to understanding the behavior of native grasses for sustainable management in the flooded savannah ecosystem. Full article