Semiarid Region Of Argentina Research Articles

The multiscale nexus among land use-land cover changes and water quality in the Suquía River Basin, a semi-arid region of Argentina

Agricultural intensification and urban sprawl have led to significant alterations in riverscapes, and one of the critical consequences is the deterioration of water quality with significant implications for public health. Therefore, the objectives of this study were the assessment of the water quality of the Suquía River, the assessment of LULC change at different spatial scales, and the analysis of the potential seasonal correlation among LULC change and Water Quality Index (WQI). The Sample Sites (SS) 1 and 2 before Cordoba city had the highest WQI values while from SS3 the WQI decreased, with the lowest WQI close to the wastewater treatment plant (SS7) after Cordoba city. From SS8 in a agricultural context, the WQI increases but does not reach the original values. In light of analysis carried out, the correlation between water quality variables and the different LULC classes at the local and regional scales demonstrated that WQI is negatively affected by agricultural and urban activities, while natural classes impacted positively. The spatialization of the results can help strongly in assessing and managing the diffusion of point and non-point pollution along the riverscape. The knowledge gained from this research can play a crucial role in water resources management, which supports the provision of river ecosystem services essential for the well-being of local populations.

Integrated water quality assessment of two Rivers Basins from a semiarid region of Argentina.

The Tunuyán and Mendoza River Basins (Province of Mendoza, Argentina) have been selected as a representative semiarid region to test the applicability of an integrated water quality evaluation. To detect spatio-temporal variations of anthropic contamination, physicochemical and bacteriological parameters, as well as three ecotoxicological assays, were assessed in reference sites for 3years. Bioassays based on the nematode Caenorhabditis elegans, the vascular plant Lactuca sativa, and the algae Pseudokirchneriella subcapitata were performed and toxicological categories were established. Our results showed that water quality, as well as water toxicity, deteriorates as both river systems run through urban areas. Interestingly, monitoring sites with good physicochemical and bacteriological qualities but with toxicity were identified, illustrating that traditional water quality studies do not predict potential toxic effects on living organisms. In addition, a multivariate statistical analysis was performed to detect clusters of monitoring sites according to the water quality status. In the context of climate change, this study provides information to support that integrated water monitoring is an essential tool to ensure sustainable water management and to guarantee economic growth, human health, food security, and environmental protection.

Influence of Experimental Warming on the Rate and Duration of Fruit Growth and Oil Accumulation in Young Olive Trees (cvs. Arbequina, Coratina).

Olive tree cultivation in new warmer areas and climate change have increased the global interest in understanding how air temperature affects both fruit growth and oil accumulation. The aims of this study were to evaluate the rate and duration of fruit growth and oil accumulation in response to experimental warming (+3) in a semiarid region of Argentina; and assess how warming affected fatty acid composition. Young, potted olive trees (cvs. Arbequina, Coratina) were warmed (T+) or maintained near ambient temperature (T0) inside open top chambers in the field during oil accumulation in 2014-2015 or 2015-2016 using different trees in each season. Warming reduced the rate of both fruit growth and oil accumulation in T+ compared to T0 in both cultivars. These rate reductions under T+ led to large decreases in final fruit dry weight and oil concentration. In contrast, the durations (i.e., days) of fruit growth and oil accumulation were most often not affected. Cultivar x temperature interactions were observed in 2014-2015 with warming decreasing oleic acid and increasing linoleic acid in cv. Arbequina, while cv. Coratina showed no response to warming. However, no interactions were found in 2015-2016. Studying how fruit growth and oil accumulation respond to adaptation strategies against increasing air temperatures should be a priority in both young and mature olive trees of numerous cultivars given crop expansion to new regions and future climate scenarios.

Influence of land‐use changes on microbial community structure and diversity in a semiarid region

AbstractLand‐use change and the conversion of land into croplands is one of the main drivers of soil degradation and the loss of soil organic carbon. Few studies have evaluated the impact of the expansion of the agricultural frontier on soil microbial communities in the Gran Chaco region in South America; therefore, the objective of this study was to explore how soil microbial communities respond to land‐use changes in a semiarid region of Argentina. The land uses selected were total and selective clearing with livestock (TC‐livestock and SC‐livestock), total clearing with agriculture (TC‐agriculture), and an undisturbed site (R‐Chancaní). Our results suggest that microbial abundances were strongly influenced by seasonal changes. In both seasons, the lowest values of total microbial biomass were observed in TC‐agriculture and TC‐livestock. In the wet season, TC‐agriculture had the lowest fungal abundance, and both total clearing sites (TC‐livestock and TC‐agriculture) had higher bacterial abundance than the other sites. Our data also showed that the Shannon and richness indices were highest at the farming sites, indicating a similar tendency in the diversity indexes in both dry and wet seasons. According to Pearson correlation analysis, humic substance (HS) content was a key driver influencing soil microbial communities, demonstrating that high HS content may significantly increase bacteria, fungi, and total phospholipid fatty acids. Microbial composition highly depended on seasonal changes. Overall, our results suggest that land‐use change altered microbial community structure and bacterial diversity, and that HS content played a crucial role in driving changes in soil microbial composition.

Gastrointestinal nematodes and mineral deficiencies in yearling cattle in Santiago del Estero, northern Argentina.

The aims were to study the epidemiology and the effect of gastrointestinal nematodes (GINs) on yearling cattle in a semiarid region in Argentina and to evaluate the mineral serum levels. Ten- to twelve-month-old calves were monitored between November and April 2019. Animals were divided into three groups: untreated control (CONG; n = 20); group treated with moxidectin (MXD, 200µg/kg) every 30-40days (MXDG; n = 20); group equally MXD treated and mineral supplementation administered in November and January (MMG; n = 20). Individual GIN egg counts (epg) and fecal cultures were made every 30-40days. Animal live weight gain was determined. On 7-11-18, 25-1-19, and 3-4-19, serum levels of Se, Cu, Zn, Mg, and Ca were determined by atom absorption spectrophotometry. At the start of the trial, epg values were low (x̄ = 5.5), which increased only in CONG towards the end of the assay (x̄ = 229). In both GMXD and MMG, epg remained very low (x̄ = 4.1). Cooperia spp. (81%) prevailed over Haemonchus spp. (9%) and Oesophagostomum spp. (9%). Deficiency of Se ranged between marginal and important, except for MMG, although mean values were always below normal. Cu was marginally deficient in CONG and MXDG on the first two sampling dates, whereas MMG had normal values after treatment. Mg had low values in the three groups (x̄ = 1.5mg/dl), whereas Ca and Zn exhibited normal values. Live weight gain (LWG) was higher in MMG than in MXDG, with significant differences (p < 0.05) by mid-January and then, when epg increased, dewormed groups showed higher LWG (p < 0.034) than CONG. A negative effect of GINs on LWG was observed, as well as low to marginal levels of Se, Cu, and Mg.

Flower beverages of native medicinal plants from Argentina (Acacia caven, Geoffroea decorticans and Larrea divaricata) as antioxidant and anti-inflammatory

Ethnopharmacological relevanceHerbal beverages have been used as a natural part of the medicinal and food culture in northwestern Argentina. The flower beverages (infusion or decoction) of Acacia caven, Geoffroea decorticans and Larrea divaricata, three native species from arid and semiarid regions of Argentina are widely used as anti-inflammatory and anti-rheumatic by several local communities. Aim of the studyThe aim of this study was to analyze the phytochemical composition of some Argentine flower beverage and to validate its traditional use as an antioxidant and anti-inflammatory agent. Materials and methodsPhenolic profiles from all flower infusions and decoctions were analyzed by both spectrophotometric analysis and HPLC-DAD. ABTS•+; the scavenging activity of both hydrogen peroxide and hydroxyl radical was determined and finally, their ability to inhibit pro-inflammatory enzymes, such as xanthine oxidase (XOD), and lipoxygenase (LOX) was also assessed. ResultsThe flower beverages of all assayed species showed a high level of phenolic compounds with similar chromatographic patterns in both infusions and decoctions of each plant species, the major components of which have been identified. The flower beverages, especially G. decorticans infusion and decoctions, displayed an important antioxidant activity (SC50 values between 18.14 and 47 μg/mL) through different mechanisms; all of them were able to inhibit the XOD enzyme activity and, consequently, the formation of uric acid and reactive oxygen species, the primary cause of arthritis-related diseases. The most active beverages as XOD inhibitor were G. decorticans flower infusion and decoctions (IC50 values of 20 and 35 μg/mL, respectively). Pro-inflammatory enzymes, such as LOX, were also inhibited by infusions and decoctions of G. decorticans, L. cuneifolia and A caven flowers, lessening inflammation mediators in all beverages. ConclusionsThe present work validates the traditional medicinal use of flower beverages from Argentina as an anti-rheumatic and anti-inflammatory agent as it has been used for hundreds of years in several pathologies associated with oxidative stress.

Temporal integration of remote‐sensing land cover maps to identify crop rotation patterns in a semiarid region of Argentina

AbstractCrop rotations are key agronomic tools to enhance farm productivity, preserve soil, and ensure provision of ecosystem services. Knowledge of the spatio‐temporal distribution of crops over regions is essential to characterize rotations at field scale and estimate their impacts on several outcomes. Our objectives were to: (a) determine the diversity of cropping systems practiced in a semiarid region of central Argentina during an 8‐yr period and (b) use the generated high‐resolution crop rotation map jointly with estimates of soil erosion to evaluate the potential linkage between cropping sequences and water erosion intensity. Temporally aggregated seasonal land‐cover maps were used to derive spatially explicit crop rotations during 2011–2018 across a 6,000 km2 semiarid agricultural region in Argentina. Soybean (Sy) [Glycine max (L.) Merr.] and maize (Mz) (Zea mays L.) defined the major crop rotations of the study area. Sorghum [Sorghum bicolor (L.) Moench] and peanut (Arachis hypogaea L.) occupied minor areas and thus were assimilated into the dominant summer cropping systems. Only seven sequences of summer crops, most of them including soybean and maize, accounted for &gt;90% of the spatio‐temporal variability. Soybean monoculture was the dominant cropping system (28.5%), followed by a 3‐yr Sy–Sy–Mz rotation (23.9%), and other soybean‐dominated rotation patterns. In winter, the prevailing land cover was stubble (96.6%). The generated high‐resolution maps illustrate the low diversity of crops in the study area. Mapping the spatio‐temporal distribution of land cover allowed for quantification of land transformations and the examination of linkages between soybean monocropping and erosion.

Do ecosystem insecurity and social vulnerability lead to failure of water security?

Achieving water security for humans and ecosystems is a pervasive challenge globally. Extensive areas of the Americas are at significant risk of water insecurity, resulting from global-change processes coupled with regional and local impacts. Drought, flooding, and water quality challenges pose significant threats, while at the same time, rapid urban expansion, competing water demands, river modifications, and expanding global markets for water-intensive agricultural products drive water insecurity. This paper takes a social-ecological systems perspective, aiming to identify examples and pathways towards resilient ecosystems and social development. It draws on lessons from two science-policy network projects, one focusing on water scarcity in arid and semi-arid regions of Argentina, Chile, Brazil, Peru, Mexico and the United States; and the second addressing river and lake basins as sentinels of climate variability and human effects on water quantity and quality in Canada, the United States, Argentina, Colombia, Uruguay and Chile. Together, these ‘complementary contrasts’ provide an analytical basis to empirically examine stakeholder engagement, knowledge co-production and science-policy interaction supporting decision-making to achieve water security. The paper identifies four tenets for decision-making based on water-security-focused global-change science in the Americas: 1) Decision makers should focus on protecting ecosystems because water security (along with food and energy security) depend on them; 2) Water-use and allocation decisions ought to be made considering future environmental and societal vulnerabilities, especially climate projections; 3) Holistic approaches (at basin or other appropriate levels) are best suited to ensure social-ecological system resilience and reduce vulnerability; and 4) It is essential to support local/traditional livelihoods, and underserved populations to achieve equitable water security and ecosystem resilience.

Effect of cattle trampling and farm machinery traffic on soil compaction of an Entic haplustoll in a semiarid region of Argentina.

Effect of cattle trampling and farm machinery traffic on soil compaction of an Entic haplustoll in a semiarid region of Argentina.

Antigenotoxic, antiproliferative and antimetastatic properties of a combination of native medicinal plants from Argentina

Ethnopharmacological relevanceJarilla is the common name of an appreciated group of native plants from the semi-arid region in Argentina (Larrea cuneifolia Cav., Larrea divaricata Cav. and Zuccagnia punctata Cav.) that have been historically consumed to heal respiratory, musculoskeletal and skin ailments, as well as recommended for weakness/tiredness, hypertension, diabetes and cancer treatment. It was previously reported that some biological properties could be improved when these plants are used jointly. Infusions of a defined mixture, composed by three Jarilla species, L. cuneifolia: L. divaricata: Z. punctata (0.5:0.25:0.25) (HM2) showed synergistic and additive effect on antioxidant activity even after passing through the gastro-duodenal tract. Aim of the studyThe main purpose of this work was to evaluate antigenotoxic, antitumor, and anti-metastatic properties of the Jarilla species that grow in the Northwest of Argentina and a herbal combination of them. Material and methodsInfusions of Jarilla mixture (HM2), and of each single plant species were prepared. Phenolic profiles of infusions were analyzed by HPLC-ESI-MS/MS and two relevant chemical markers were quantified. The antigenotoxic activity was evaluated by using the Ames test and the Cytokinesis-Block Micronucleus (CBMN) assay against direct mutagens. Evaluations of both cytotoxicity and antiproliferative effects were conducted on tumor and non-tumor cell lines. Both in vivo tumoral growth and metastasis inhibition were evaluated by using a carcinoma model on Balb/c mice. ResultsHM2 mix could suppress genetic and chromosome mutations induced by 4-nitro-o-phenylendiamine (4-NPD) and doxorubicin. Herbal mixture and single plant infusions showed cytotoxic effect against mammary, uterus, and brain tumoral cells without a selective action vs normal human cell line. HM2 mix was able to reduce mammary tumor mass on the Balb/c mice model and showed a significant reduction in the number of metastatic nodules in the lungs. ConclusionsOur results suggest that the combinations of three Jarilla species from northwest Argentina would be a promising alternative to treat or slow down the development of chronic diseases, such as cancer.

Pesticides in water sources used for human consumption in the semiarid region of Argentina

Presence of pesticides in drinking water is an issue of great concern in agricultural areas. In Argentina’s semiarid regions, where surface water sources are scarce and groundwater may be of poor quality, rainwater becomes important for safe water supply. The expansion of agriculture in these regions due to no till management has led to a high use of pesticides which jeopardize the safety of all water sources used for human consumption. The objective was to monitor the presence of pesticides in different water sources from two agricultural areas of Santiago del Estero. Samples belonged to cisterns in which rainwater is collected, wells and dams. The most contaminated sources were dams, followed by cisterns and wells. Applied doses and frequency of use played an important role in the presence of pesticides. Thus, the most frequent molecules were mainly herbicides; atrazine and metolachlor were the most abundant. Glyphosate and aminomethylphosphonic acid presented the highest concentrations. Almost all measured values were below the US Environmental Protection Agency limits, but 73% of the samples exceeded the limit of 0.5 μg L−1 established by the European Union for the sum of molecules although only 7.4% of individual molecules exceeded the limit of 0.1 μg L−1. However, risk assessment showed that pesticides from all sources presented a low potential risk to human health through drinking water exposure route.

Active properties of edible marine polysaccharide-based coatings containing Larrea nitida polyphenols enriched extract

The aim of this work was to develop active edible coatings based on marine polysaccharide matrices and polyphenols-enriched native plant extracts from arid and semiarid regions of Argentina. Initially, five plant extracts were characterized in terms of antioxidant, antibacterial and antiviral activity and the one with better biological properties and no toxicity or genotoxicity, Larrea nitida (Ln) extract, was incorporated into agar, alginate or agar/alginate matrices. The Ln extract-containing films were characterized in terms of physicochemical and polyphenols release performance in food simulants. The incorporation of Ln extract provided darker films, with a more saturated orange-brownish color and with negligible effects on mechanical and barrier properties. Additionally, all the coatings showed antiviral activity when applied to blueberries against murine norovirus (MNV), a cultivable norovirus surrogate. The coatings of agar and Ln extract was able to reduce the infectivity of MNV below the limit of detection after over-night (ON) incubation at 25 °C and after 4 days at 10 °C storage.These edible polysaccharides coatings containing Ln extract could be an alternative to reduce or eliminate foodborne viruses and protect the food against oxidative process.

Expansion of maize production in a semi-arid region of Argentina: Climatic and edaphic constraints and their implications on crop management

The Southwestern Pampas (SWP) is a semi-arid region of Argentina with the presence of a widespread caliche layer that limits soil depth. In this region, maize production has recently expanded with scarce information on appropriate management practices. The objective of this work was to provide an agro-climatic and eco-physiological framework of cultural changes of maize cropping systems of the SWP and the main implications of the climatic and edaphic constraints on crop management decisions. The work combined i) public data of regional maize cultivated area for the period 2008–2015 alongside with farmers’ cropping management trends related to sowing dates and plant population density (PPD); ii) on-field experimental data generated from trials in different sites in the SWP sown at different dates, soil depths and PPDs; and iii) a crop water-economy characterization with a probabilistic approach by means of historical climatic series (identifying the El Niño Southern Oscillation (ENSO) phases) in three locations in the SWP across a longitudinal range between the 800 mm and 600 mm isohyets. In the 2008–2015 period, maize area increased five-fold, median sowing date delayed one month and PPD decreased from ca. 7.2 pl m-2 to 3.4 pl m-2. Late-sown crops (7564 kg ha-1; CV = 19%) out-yielded early-sown crops (5888 kg ha-1; CV = 42%) with less variability across environments. Crop evapotranspiration during the cycle (ETacycle) slightly decreased (P50 = 3–32 mm lower) with the delay of sowing, but the proportion of crop evapotranspiration during the reproductive period was significantly higher. ETacycle of late crops did not vary within PPD, but transpiration per plant decreased with PPD and increased in deep soils, especially at low densities. The impacts of sowing date and PPD did not vary among ENSO phases, not supporting the use of ENSO as a decision criterion for maize management in the SWP.

Risks of cattle babesiosis (Babesia bovis) outbreaks in a semi-arid region of Argentina

The epidemiology of Babesia bovis was studied in terms of enzootic stability/instability and husbandry and abiotic factors influencing B. bovis transmission rate in northeastern Santiago del Estero province, Argentina. The area is of limited suitability for its only vector in Argentina, the tick Rhipicephalus microplus. The proportion of calf herds in a state of enzootic stability/instability to B. bovis was determined and husbandry practices and abiotic factors associated with variations in B. bovis transmission rates were explored using a cross-sectional observational study design. Daily probability of infection (inoculation rate, h) with B. bovis was calculated from age-specific seroprevalence via ELISAi in 58 herds of 4.5–8.5-month-old calves. Herds were considered to be in enzootic instability (EI) when h < 0.005, and therefore inferred to be at risk of babesiosis outbreaks. Husbandry practices associated with differences in B. bovis transmission were analyzed using generalized linear models. Sixty-two percent of herds were found to be in an EI situation for B. bovis. Calves raised exclusively on permanent pastures –where higher cattle density is achieved– were exposed to higher B. bovis inoculation rates (h = 0.0063, 95% CI 0.0032-0.0123) than those reared under forage combinations (h = 0.0024, 95% CI 0.0011-0.0051) (P = 0.05). In addition, calves from herds located in the area of intermediate suitability for R. microplus development were more likely to become infected with B. bovis (h = 0.0067, 95% CI 0.0037-0.0121) than those reared in the ecologically unfavorable area for the vector (h = 0.0023, 95% CI 0.0010-0.0049) (P = 0.02). Neither the frequency of treatment with acaricides nor the use of long-acting acaricides to control R. microplus influenced the inoculation rate (P = 0.99 and P = 0.26, respectively). This result indicates that current R. microplus control schemes are not effective in reducing B. bovis transmission. Enzootic instability still prevails in the study area despite the drastic changes occurred in cattle production system. However, 38% of herds did reach enzootic stability; therefore, a specific epidemiological status cannot be assumed at a regional level. Yearly determination of the immunological status of each calf cohort is considered a proper approach to decision-making in vaccination against B. bovis.

A High-Density Linkage Map of the Forage Grass Eragrostis curvula and Localization of the Diplospory Locus.

Eragrostis curvula (Schrad.) Nees (weeping lovegrass) is an apomictic species native to Southern Africa that is used as forage grass in semiarid regions of Argentina. Apomixis is a mechanism for clonal propagation through seeds that involves the avoidance of meiosis to generate an unreduced embryo sac (apomeiosis), parthenogenesis, and viable endosperm formation in a fertilization-dependent or -independent manner. Here, we constructed the first saturated linkage map of tetraploid E. curvula using both traditional (AFLP and SSR) and high-throughput molecular markers (GBS-SNP) and identified the locus controlling diplospory. We also identified putative regulatory regions affecting the expressivity of this trait and syntenic relationships with genomes of other grass species. We obtained a tetraploid mapping population from a cross between a full sexual genotype (OTA-S) with a facultative apomictic individual of cv. Don Walter. Phenotypic characterization of F1 hybrids by cytoembryological analysis yielded a 1:1 ratio of apomictic vs. sexual plants (34:27, X2 = 0.37), which agrees with the model of inheritance of a single dominant genetic factor. The final number of markers was 1,114 for OTA-S and 2,019 for Don Walter. These markers were distributed into 40 linkage groups per parental genotype, which is consistent with the number of E. curvula chromosomes (containing 2 to 123 markers per linkage group). The total length of the OTA-S map was 1,335 cM, with an average marker density of 1.22 cM per marker. The Don Walter map was 1,976.2 cM, with an average marker density of 0.98 cM/marker. The locus responsible for diplospory was mapped on Don Walter linkage group 3, with other 65 markers. QTL analyses of the expressivity of diplospory in the F1 hybrids revealed the presence of two main QTLs, located 3.27 and 15 cM from the diplospory locus. Both QTLs explained 28.6% of phenotypic variation. Syntenic analysis allowed us to establish the groups of homologs/homeologs for each linkage map. The genetic linkage map reported in this study, the first such map for E. curvula, is the most saturated map for the genus Eragrostis and one of the most saturated maps for a polyploid forage grass species.

Pollen contamination and mating patterns in a Prosopis alba clonal orchard: impact on seed orchards establishment

Abstract: Prosopis alba (Leguminosae) is an important species from ecologic and economical points of view in arid and semi-arid regions of Argentina. In several open-pollinated species, pollen contamination from off-orchard parents and selfing have been proven to reduce orchard seed quality. In 2002, the first clonal orchard of Prosopis alba was established in Fernandez (Santiago del Estero, Argentina) with 12 trees phenotypically selected from a progeny trial, based on height, pod production per year and pod sweetness. The aim of this study was to evaluate the mating patterns and pollen contamination rate in the orchard using ten SSR markers and paternity analysis. All the clones together with the progeny of a single clone (open-pollinated seeds) were genotyped. Data was processed by two different methods based on likelihood and Bayesian approaches, respectively. A high consistency (89%) of results was observed between the two methods, and pollen contamination rate was estimated between 27% and 37%. The minimum number of different pollen donors per mother plant varied from three to five and selfing occurrence was low (<1.6%). Based on the estimated status number (Ns = 4.4), the expected coancestry in the seed crop is equal to a Mendelian population with an effective size of 4-5 individuals. Genetic analyses are encouraged during the establishment and monitoring of trials in forest breeding and management programmes. It is strongly recommended to establish seed orchards in isolated areas and to guarantee equal representation of parental genotypes in the orchards.

The water-energy-food nexus of unconventional oil and gas extraction in the Vaca Muerta Play, Argentina

Vaca Muerta is the major region in South America where horizontal drilling and hydraulic fracturing techniques are used to extract unconventional shale oil and gas. Despite the growing interest in the Vaca Muerta resources, there is only a limited understanding of the impacts that their extraction could have on local water resources. This study uses a water balance model to investigate the hydrological implication of unconventional oil and gas extraction in this region. We find that, with current rates of extraction, water scarcity is observed for four months a year. We also find that water consumption per fractured well increased 2.5 times in the period 2012–2016 and produced water from unconventional shale formation sharply increased from roughly zero to 1.15 × 106 m3 y−1 in the 2009–2017 period. Our projections estimate that in this region future water consumption for unconventional oil and gas extraction will increase 2.2 times in the 2017–2024 period reaching 7.40 × 106 m3 y−1. The consequent exacerbation of current water scarcity will likely lead to competition with irrigated agriculture, the greatest water consumer in this semiarid region. Produced water recycling, domestic wastewater reuse, brackish groundwater use, and waterless unconventional oil and gas extraction technologies are some of the strategies that could be adopted to meet future additional water demand. Our results estimate the likely range of water consumption and production from hydraulic fracturing operations in the Vaca Muerta region under current and future conditions. These results could be used to make informed decisions for the sustainable water management in this semiarid region of Argentina.

Nuevo registro del huroncito patagónico (Lyncodon patagonicus, Carnivora: Mustelidae) para el centro de Argentina y aportes sobre su historia natural

The Patagonian weasel ( Lyncodon patagonicus ) inhabits arid and semiarid regions of Argentina and Chile. Most references come from ancient records, recent observa- tions are scarce. Although the species has been known for more than a century and has a wide distribution, knowledge about its natural history is limited. In this work, a new locality is documented for this species, based on a single specimen observed and photographed at Chancani Natural Reserve, Cordoba Province, Argentina. It also provides information about its natural history, since the individual was seen feeding on a specimen of Ctenomys sp. during the day . Therefore, we confirm the presence of the Patagonian Weasel in the province of Cordoba, whose most reliable record of the species comes from Late Pleistocene.

Mathematical modelling for ecohydrological management of an endangered endorheic salt lake in the semiarid Pampean region, Argentina

In this work, we propose a mathematical model within a dynamic optimization framework to address the management of a salt lake in a semiarid region in Argentina (Chasicó Lake). The main objective is to elaborate strategies to control recurrent floods and keep salinity values around the physiological optimum for the high-commercial value fish silverside. The model comprises dynamic mass balances for water and salt, as well as evaporation calculation based on energy and momentum balances on a daily basis. A collection of meteorological and hydraulic data in the basin for several decades and bathymetric information is included. The simulation of different scenarios with historical data provide a deeper insight into the ecohydrological dynamics of Chasicó Lake basin. Model predictions under moderate drought conditions, with rainfall about 70% of the historic average, show a large increase in salinity after three years under that setting. This would induce drastic changes in ecological conditions producing fish mass mortality, what likely occurred repeatedly throughout the lake’s history, since such dry periods occurred repeatedly during the analyzed 1911‐2016 period. The comparison between drought and wet scenarios indicates a differential vulnerability dynamics in which the system shows less resistance to the effects of drought than to those due to floods. The proposed model allows the determination of optimal lake tributary diversion flowrate to prevent flooding of croplands, keeping lake salinity within optimal values for silverside, and providing water for the creation of wetlands for wildlife and an artificial reservoir for alleviation of wet period effects.

Lectotypifications, epitypifications and neotypifications in Zygophyllaceae species from South America

Zygophyllaceae in South America is mostly represented by members of the subfamily Larreoideae, which distinguishes the arid and semi-arid regions of Argentina and Chile. The subfamily Tribuloideae is also distributed in the Southern Cone but represented only by three species in Argentina. Currently there are no actualized taxonomic studies of the family that may help to understand its origin and diversification and to serve as a framework for phylogenetical analyses. In this context, the present study provides 9 lectotypifications, 2 epitypifications and 2 neotypifications of names of Zygophyllaceae species from Argentina, Chile, Brazil and Bolivia.