Search Results (91)

Planning conservation for multiple species while accounting for habitat availability and connectivity under uncertain land-use changes presents a major challenge. This study proposes a protocol to identify strategic conservation areas by assessing the functional connectivity of key bird species under future land-use scenarios in the Chaco Serrano of Córdoba, Argentina. We modeled three land-use scenarios for 2050: business as usual, sustainability, and intensification. Using the Equivalent Connected Area index, we evaluated functional connectivity for Chlorostilbon lucidus, Polioptila dumicola, Dryocopus schulzii, Milvago chimango, and Saltator aurantiirostris for 1989, 2019, and 2050, incorporating information about habitat specialization and dispersal capacity to reflect differences in ecological responses. All species showed declining connectivity from 1989 to 2019, with further losses expected under future scenarios. Connectivity declines varied by species and were not always proportional to habitat loss, highlighting the complex relationship between land-use change and functional connectivity. Surprisingly, the sustainability scenario led to the greatest losses in connectivity, emphasizing that habitat preservation alone does not ensure connectivity. Using the Integral Connectivity Index, we identified habitat patches critical for maintaining connectivity, particularly those vulnerable under the business as usual scenario. With a spatial prioritization analysis we identified priority conservation areas to support future landscape connectivity. These findings underscore the importance of multispecies, connectivity-based planning and offer a transferable framework applicable to other regions. Full article

(1) Background: Changes in the spatial, temporal, and magnitude-related patterns of fires caused by humans are expected to exacerbate with climate change, significantly impacting ecosystems and societies worldwide. However, our understanding of fire regimes in many regions remains limited, largely due to the inherent complexity of fire as an ecological process. Pyrogeography, combined with unsupervised learning methods and the availability of long-term satellite data, offers a robust framework for approaching this problem. The purpose of the study is to identify the pyroregions of the Argentine Gran Chaco, the world’s largest continuous tropical dry forest region. (2) Methods: Using globally available fire occurrence datasets, we computed five fire metrics, related to the extent, frequency, intensity, size, and seasonality of fires at three spatial scales (5, 10, and 25 km). In addition, we tested two widely used cluster algorithms, the K-means algorithm and the Gaussian Mixture Model (GMM). (3) Results and Discussion: The identification of pyroregions was dependent on the clustering algorithm and scale of analysis. The GMM algorithm at a 25 km scale ultimately demonstrated more coherent ecological and spatial distributions. GMM identified six pyroregions, which were labeled based on three metrics in the following order: annual burned area (categorized in low, regular or high), interannual variability of fire (rare, occasional, frequent), and fire intensity (low, moderate, intense). The values were as follows: LRM (22% of study area), ROI (19%), ROM (14%), LOM (10%), ROL (9%), and HFL (4%). (4) Conclusions: Our study provides the most comprehensive delineation of the Argentine Gran Chaco’s Dry Forest pyroregions to date, and highlights both the importance of determining the optimal scale of analysis and the critical role of clustering algorithms in efforts to accurately characterize the diverse attributes of fire regimes. Furthermore, it emphasizes the importance of integrating fire ecology principles and fire management perspectives into pyrogeographic studies to ensure a more comprehensive and meaningful characterization of fire regimes. Full article

(1) Background: Land-use change threatens biodiversity globally, making it essential to anticipate future impacts. (2) Methods: We assess future land-use change scenarios as a tool for analyzing the taxonomic and functional richness of birds in the Serrano forest. We developed two change scenarios: The “Business as usual” scenario assumes that the trend of land-use change observed between 2004 and 2019 will continue without modifications by 2035 and 2050. The “Sustainable” scenario seeks to achieve a sustainable relationship between anthropogenic land-use activities and ecosystem conservation. We created distribution models and derived the potential distribution of the taxonomic and functional richness of forest and understory specialist birds in the change scenarios. (3) Results: The taxonomic and functional richness of both bird groups was strongly affected in the “Business as usual” change scenario, which presented extreme deforestation events, while the “Sustainable” change scenario tended to maintain bird richness over time. We detected areas with a reduction in richness greater than 20% and areas where richness increased due to being distant from urbanization and exotic forests. Full article

Soil organic carbon (SOC) stocks play an important role in ecosystem functioning and climate regulation. These stocks are declining in many tropical dry forests due to land-use change and degradation. Data on topsoil (0–300 mm) organic C stocks from six experiments conducted in the Dry Chaco region, the world’s largest dry tropical forest, were used to test the predictive performance of the Rothamsted Carbon Model (RothC) after its implementation in an object-oriented graphical programming language. RothC provided promising predictions (i.e., precise and accurate) of the SOC stocks under two representative land covers in the region, native forest and Rhodes grass [relative prediction error (RPE) < 10%, concordance correlation coefficient (CCC) > 0.9, modelling efficiency (MEF) > 0.7]. Comparatively, model predictions of the SOC stocks under degraded Rhodes grass swards were suboptimal. The predictions were sensitive to C inputs; under native forests and Rhodes grass, a high C input improved the predictive performance of the model by reducing the mean bias and increasing the MEF values, compared with mean and low C inputs. Larger datasets and revisiting some of the underlying assumptions in the SOC modelling will be required to improve the model’s performance, particularly under the degraded Rhodes grass land cover. Full article

The extant Patagonian mara Dolichotis patagonum (Zimmermann, 1780) is a cursorial herbivorous rodent that is hare-like in appearance. Nowadays, it occurs in some ecoregions of Argentina (28 °S–50 °S) in lowland habitats, in semi-arid thorn-scrub, in open grasslands and in shrub–land steppe. In this research, we have studied a partially preserved skull (FCDPV-2758), referred to D. patagonum, from the Late Pleistocene (Sopas Formation) in northern Uruguay (Arapey Grande River, Salto Department). Body mass estimates and morphological analyses were performed including contemporary specimens of D. patagonum, the Chaco mara Dolichotis salinicola, and extinct dolichotine species. The body mass estimate using the regression method and geometric similarity suggested a 6–8 kg range for the studied specimen, which is consistent with D. patagonum (7–8 kg) and notably greater than D. salinicola (1–2.3 kg). A comparative analysis, including the extinct D. platycephala and material previously referred to D. major from southwestern Uruguay, suggests that the studied specimen falls within the variation of D. patagonum, differing in part from D. chapalmalense and more clearly from D. salinicola, the extinct D. minor and Prodolichotis prisca. The implications of the wider geographic distributions of the living Patagonian mara at these latitudes in the Late Pleistocene in South America, and the paleoenvironmental significance are discussed. Full article

In this work, we performed the genetic characterization of a new variant of orthohantavirus associated with a fatal case of hantavirus pulmonary syndrome, outside the known endemic region, in northwestern Argentina. We first confirmed an orthohantavirus infection by ELISA, testing for the detection of IgM and IgG antibodies. Then, we extracted RNA from 100 microliters of serum, the only sample available, followed by RT-PCR. The amplicons were sequenced using Sanger and next-generation sequencing technology. We obtained partial sequences of 1253 bp, 799 bp and 1675 bp from the S-, M- and L-segments, respectively, showing low sequence identities with all the previously characterized hantaviruses (10.9%, 13.5% and 15.1% of the divergence, respectively). The phylogenetic analysis showed that this virus belongs to the Orthohantavirus andesense species (ANDV), and among the ANDV-like variants, it is more closely related to the Lechiguanas clade. Similar percentages of divergence were considered sufficient to distinguish AND-like variants in previous works. As the patient had no travel history before the onset of disease was reported, we conducted rodent surveys to confirm the presence of reservoirs. The rodent assemblage was compatible with the transitional zone among different ecoregions (Yungas, Chaco and Monte). Moreover, one of the species captured, Oligoryzomys flavescens, was previously described as a reservoir of hantavirus. This species may either host several variants across its range or encompass a species complex, as proposed by some authors. Full article

The current range of the jaguar (Panthera onca) spans sixty degrees of latitude across eighteen countries in the Western Hemisphere and covers approximately 7,000,000 km². Throughout this geographical breadth, jaguars represent an essential component of native biological diversity, but conflict revolving around real and perceived jaguar depredation on livestock is a factor in jaguar mortality. We developed a structured questionnaire to evaluate the effectiveness of anti-depredation strategies from northern Mexico to Argentina, collecting data from 11 countries and 248 livestock operations, 194 with efficacy metrics, and 24 with benefit–cost ratios (value of the livestock losses averted/cost of the intervention). Using coarse categories, 11 intervention types were tested. Techniques effectively reducing livestock losses were documented across the entire livestock operation size (2–130,000 ha, 5–30,000 head) and biome spectrum. While the techniques varied in complexity and required levels of investment, successful reductions in depredation were achieved at all levels. We conclude that anti-depredation strategies are highly effective, and when benefits are evaluated, they surpass costs, sometimes substantially. Given the proven efficacy and cost-effectiveness of the techniques described in this paper, we advocate for broader application across the species range to increase tolerance towards jaguars and a more effective human–jaguar coexistence. Full article

Furfural is a relevant industrial product, but its presence in water and soil generates contamination and health risks. Moving bed biofilm reactors (MBBRs) are an increasingly used alternative to eliminate contaminants with the advantage of occupying small spaces, despite their high dependence on support and the microorganisms involved in the process. This work proposes furfural elimination through a laboratory-scale MBBR using Bacillus licheniformis GTQ1, Microbacterium sp. GISTAQ2, and Brevundimonas sp. GISTAQ1 isolated from an industrial effluent and agroforestry waste (rice husks, pine sawdust, and quebracho chips) as supports. The biofilm development was tested with both axenic and mixed cultures, confirming high coverage by Scanning Electron Microscope (SEM) images, especially in triple-mixed cultures. Biodegradation tests were carried out in the MBBR with 15 g rice husks or quebracho chips as supports and a 4000 mg L⁻¹ initial furfural concentration for 72 h. The mixed culture achieved almost a 100% furfural removal in three days with a rate of 3.97% per hour with rice husks and 2.61% per hour with quebracho chips. This laboratory-scale MBBR development is a promising first step ready for a scale-up for its implementation in industries to significantly reduce the environmental impact of the discharge of this type of effluent. Full article

Lithium-ion batteries are essential for electric vehicles, requiring critical resources such as lithium and cobalt. Paraguay’s integration into the electric vehicle supply chain presents an opportunity to leverage its renewable energy and strategic location. This study evaluates potential partners for Paraguay to establish a lithium-ion battery and electric vehicle assembly plant in the Chaco region. A multi-criteria decision analysis using the Analytic Hierarchy Process and expert opinions assessed Argentina, Brazil, Bolivia, and Chile based on economic, energy, environmental, social, political, and geopolitical factors. The results indicate Chile as the most favorable partner (29.5%), followed by Argentina (25.9%), Bolivia (22.8%), and Brazil (21.6%). Chile’s strengths lie in its environmental policies and political stability, while Argentina offers logistical advantages and resource availability. The findings highlight strategic pathways for Paraguay’s integration into the electric vehicle supply chain and the importance of targeted collaboration to enhance regional lithium-ion battery production and commercialization. Full article

Organic acids are key components that determine the taste and flavor of fruits, playing a crucial role in maintaining fruit quality and nutritional value. To investigate the metabolic differences of organic acids between the fruit pericarp and the pulp during the developmental maturation of the Cerasus humilis, this experiment utilized Cerasus humilis cultivated in Inner Mongolia, China, as the experimental material. By measuring the malic acid and citric acid content, as well as the activities of the related metabolic enzymes in the fruit pericarp and the pulp at five developmental stages, this study investigated the characteristics of organic acid accumulation, changes in enzyme activities, and the expression trends of corresponding genes. Transcriptomic data were integrated to support the analysis. This study specifically analyzed the reasons for the differences in acidity between the pericarp and the pulp, and performed a correlation analysis of various indicators. The results indicated that, during development, the organic acid composition in both the pericarp and the pulp was primarily malic acid, with citric acid as a secondary component. The malic acid and citric acid content in the pericarp were significantly higher than in the pulp, resulting in greater overall acidity in the pericarp. The combined action of PEPC, NAD-MDH, and NADP-ME was identified as the primary reason for the differences in malic acid content between the pericarp and the pulp of Cerasus humilis. CS and ACO were identified as the key enzymes responsible for the lower citric acid content in the pulp compared to the pericarp. Furthermore, the expression levels of ChMDH2, ChME, ChCS2, ChCS3, ChACO1, and ChACO2 differed significantly between the fruit pericarp and the pulp, suggesting their regulatory roles in organic acid accumulation. Full article

In this article, we give a brief review of a well-known integral inequality that gives information about the integral of the product of two functions using synchronous functions, the Chebyshev inequality. We have compiled the most relevant information about fractional and generalized integrals, which are one of the most dynamic topics in today’s mathematical sciences. After presenting the classical formulation of the inequality using Lebesgue integrable functions, the most general results known from the literature are collected in an attempt to present the reader with a current overview of this research topic. Full article

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi that associate with the vast majority of terrestrial plants. Among non-vascular plants, while AMF associations are well-documented in liverworts and hornworts, there is a broad consensus that symbiotic associations do not occur in mosses. Here, we report the presence of AMF in the living material of mosses found in Chaco Serrano (Tucumán, Argentina). We found all characteristic structures of AMF when establishing an intimate connection with two moss species of Pottiaceae (Bryophyta). While Gertrudiella uncinicoma exhibited AMF with both Arum- and Paris-type morphologies, Pleurochaete luteola only displayed an Arum-type morphology. Plant tissue samples were subjected to high-throughput sequencing for AMF identification. We determined that Rhizophagus irregularis was a clear dominant species in both moss species, with Glomus sp. also being present as a less abundant element. In addition, we also reported the presence of vesicles, arbuscules, and spores adhered to the hyphae and the presence of septate endophytes. This finding expands our understanding of the interactions between AMF and non-vascular plants and prompt us to further characterize this interaction by considering the diversity of mycorrhizal associations with concurrent implications for the ecology of mosses and the functionality of the ecosystems. Full article

Urinary tract infections (UTIs) are common and are typically treated empirically, based on local antimicrobial resistance (AMR) data, which are often scarce in low- and middle-income countries. This study examines the AMR patterns of pathogens causing community-onset (CO) UTIs in the Bolivian Chaco. Urine samples were collected from subjects with suspected CO-UTIs and analyzed by culture techniques. Significant isolates were tested for their antimicrobial susceptibility. Additionally, bla_CTX-M and mcr genes were searched for using real-time PCR. A total of 361 CO-UTI episodes were diagnosed among 731 subjects from February 2020 to November 2021. The cases included uncomplicated and complicated UTIs (58.2% and 41.8%, respectively), with females accounting for the majority (85.3%) of cases. Escherichia coli was the most prevalent pathogen (86.6%), followed by Klebsiella pneumoniae (5.4%) and Proteus spp. (2.2%). Very high resistance rates (>50%) were observed for ampicillin, trimethoprim–sulfamethoxazole and fluoroquinolones, high resistance rates (>20%) for amoxicillin–clavulanate, third-generation cephalosporins and gentamicin, while lower resistance rates (<10%) were observed for nitrofurantoin and fosfomycin. The prevalence of bla_CTX-M among E. coli was high (26.7%). Colistin resistance was detected in 3.4% of E. coli, mostly associated with mcr genes. CO-UTIs from this area were characterized by high resistance rates to commonly used antibiotics (trimethoprim–sulfamethoxazole, amoxicillin–clavulanic acid and ciprofloxacin), highlighting the importance of knowledge of the local epidemiology to inform the selection of appropriate empirical antibiotic regimens. Full article

The arrival of psittacine in North America is well known but undefined. It is widely accepted that these birds originated in South America, and it has been suggested that different factors have promoted the biodiversity of birds in Mexico. However, in general, for North American psittacine, there are no proposed divergence times, and the possible influence of different geological events on these processes is unknown. In this study, phylogenetic relationships, divergence times, and ancestral areas of the genera Aratinga, Eupsittula, and Psittacara and related genera were estimated to propose hypotheses of the origin, diversification, and dispersal of groups under a Bayesian inference framework based on mitochondrial molecular markers. Of seven monophyletic clades within the Arini tribe, four coincided with the genera Psittacara, Eupsittula, Rhynchopsitta, and Pyrrhura, while Aratinga was grouped with Conuropsis and Cyanopsitta. Diversification of the analyzed genera probably occurred during the Miocene and around the Miocene–Pliocene boundary. The results suggest that the most likely origin of these genera is the Amazonian or Chaco regions. The diversification of these groups seems to be related to geoclimatic events associated with the uplift of the central and northern portions of the Andes and the closure of the Isthmus of Panama. We propose routes from south to north in the Neotropics and the use of the Greater and Lesser Antilles as a northward path. Full article

Anthropogenic alteration of tropical and subtropical forests is a major driver of biodiversity loss; notably, the Chaco Forest, which is the largest dry forest in the Americas, is among the most impacted regions. Sustainable forest management, a key objective of the UN’s 15th Sustainable Development Goal (SDG), underscores the need for advanced monitoring tools. This study integrates Sentinel-2 remote sensing (RS) spectral indices with field data to analyze forests under varying management regimes and levels of alteration in a representative area of the Chaco region (Chancaní Provincial Reserve and surrounding areas of the West Arid Chaco). Forest structure types and conservation levels were linked to monthly spectral index behavior using linear mixed models. Spectral indices such as the BI (Brightness Index), NDWI_Gao (Normalized Difference Water Index), and MCARI_Sent (Modified Chlorophyll Absorption in Reflectance Index) effectively differentiated forest stands by conservation status and structural alteration. This combined RS and field data approach proved highly effective for detecting and characterizing forests with diverse conservation and sustainability conditions. The methodology demonstrates significant potential as a reliable RS-based tool for monitoring forest health and supporting progress toward SDG targets, particularly in regions like the Chaco Forest, which face extensive anthropogenic pressures. Full article