Central Area Of Chile Research Articles

Filarial nematodes in domestic dogs and mosquitoes (Diptera: Culicidae) from semi-rural areas in Central Chile.

Climate change, competent vectors, and reservoir animals are the main factors for developing vector-borne zoonotic diseases. These diseases encompass a significant and widespread category of pathogens (e.g., viruses, bacteria, protozoa, and helminths) transmitted by blood-feeding arthropods, including ticks, fleas, lice, triatomines, mosquitoes, sandflies, and blackflies. In Chile, several studies have explored the role of dogs as reservoirs of vector-borne pathogens; however, there is a lack of research investigating the presence of pathogens in arthropods. Specifically, within the order Diptera, limited knowledge exists regarding their roles as carriers of pathogens. This study aimed to examine the presence of zoonotic filarial nematodes in mosquitoes and dogs within a previously unstudied semi-rural area of Central Chile. Two hundred samples of dog blood and seven hundred and twenty-four mosquitoes were collected during 2021-2022 and studied for filarial nematodes by PCR. The prevalence of microfilaremic dogs detected by Knott's test was 7.5%, with Acanthocheilonema reconditum being the only species identified. Aedes (Ochlerotatus) albifasciatus was the most abundant mosquito species collected, and 15 out of 65 pools were positive for filarial nematodes. Among these pools, 13 tested positive for Acanthocheilonema reconditum, and two tested positive for Setaria equina through PCR. Additionally, five Culex pipiens specimens were positive for Acanthocheilonema reconditum. Despite the absence of zoonotic filarial species, these findings underscore the significance of monitoring pathogens in mosquitoes and animal hosts and continued research into the dynamics of vector-borne diseases, particularly in unexplored regions.

Atitudes e percepções de pequenos agricultores em relação a associatividade: um estudo exploratório da zona central do Chile

ABSTRACT: Small-scale farmers are essential food suppliers, especially in developing countries, but they face many constraints that limit their productivity and returns. Associating with other farmers (for instance, through cooperatives) has been shown to be a strategy to mitigate these constraints; however, there are limitations in farmers’ participation and commitment to associations. This research explored small-scale farmers’ attitudes and perceptions of associations. This paper considered the district of Cauquenes, a rural area in central Chile. A total of 71 small-scale farmers were surveyed. The data were processed using descriptive, multivariate, and qualitative techniques. The results showed that the farmers had limited knowledge of and experience with associations. They also did not see participation in an association as necessary for improving their business outcomes. They were also reluctant to accept a possible loss in decision-making power or the possibility of being scammed or tricked. The factors underlying farmers’ attitudes toward associations were “Uncertainty of economic benefits” (23.3% of variance), “Technical-economic limitations perception” (15.2%), “Distrust” (10.8%), and “Individualism” (9.8%). These results suggested that policies are needed to improve farmers’ experience with and knowledge of associations, considering the cultural variables that affect distrust and focusing on existing uncertainties. The associative processes need to allow for progressive commitment, expedite tangible results, and provide continuous technical and motivational support.

Plastic debris, persistent organic pollutants and their toxicity impacts in coastal areas in Central Chile

The chemical components of plastic wastes have made their disposal a major economic, social, and environmental problem worldwide. This study evaluated the acute toxicity and genotoxicity of marine plastic debris on the beaches of Concepción Bay, Central Chile, taken during three periods (spring, summer, and winter). An integrated approach was used, including chemical and toxicological data, using the Microtox® test with Vibrio fischeri and SOS chromotest with Escherichia coli and concentrations of polychlorinated biphenyls (PCBs), Organochlorine Pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). The results presented here exclusively include the novel data obtained from the winter campaign, revealing high concentrations of PBDEs (238 ± 521 ng g−1). In addition, the genotoxicity and acute toxicity tests were sensitive for most of the samples studied. This investigation is the first attempt to analyse the toxicity of plastic debris in coastal areas along the Chilean coast.

Vaccination of Calves with the Mycobacterium bovis BCG Strain Induces Protection against Bovine Tuberculosis in Dairy Herds under a Natural Transmission Setting.

Simple SummaryBovine tuberculosis (bTB) is a zoonotic disease caused mainly by Mycobacterium bovis, of which control is based on culling infected animals and, without official compensations, is associated with major economic losses for milk and meat producers. The vaccination of cattle with the M. bovis Bacillus Calmette-Guerin (BCG) strain, as a strategy for bTB control, might attenuate this situation. The objective of this trial was to assess the efficacy of the BCG Russia strain in a cohort study performed under field conditions, with the vaccination of 501 calves in seven dairy farms, including 441 non-vaccinated control animals. Peripheral blood was collected at 6, 12 and 18 months post-vaccination, and infection status was determined using a diagnostic procedure which discriminates the infected amongst vaccinated animals. On average, the BCG vaccine showed a low but significant level of protection (22.4%) at the end of the trial, although diverse levels of protection and duration of immunity were observed between trial herds, suggesting that the efficacy of the BCG vaccination could be influenced by the general health condition of calves and their exposition to non-tuberculous mycobacteria. These results support the use of BCG as a complementary tool in the control of the disease in high prevalence areas.Bovine tuberculosis (bTB) is a zoonotic disease caused mainly by Mycobacterium bovis, which is associated with major economic losses for milk and meat producers. The objective of this trial was to assess the efficacy of the BCG Russia strain in a cohort study performed under field conditions, with the vaccination of calves in seven dairy farms from a high prevalence area in central Chile. The trial was performed with 501 animals, subcutaneously vaccinated with 2–8 × 105 colony-forming units of BCG, whilst 441 matched control animals received a saline placebo. Peripheral blood was collected at 6, 12 and 18 months post-vaccination, and infection status was determined using the IFNγ release assay in conjunction with the DIVA (Detecting Infected amongst Vaccinated Animals) antigens ESAT-6, CFP-10 and Rv3615c. The BCG vaccine showed a low but significant level of protection of 22.4% (95% CI 4.0 to 36.4) at the end of the trial. However, diverse levels of protection and a variable duration of immunity were observed between trial herds. This diverse outcome could be influenced by the general health condition of calves and their exposition to non-tuberculous mycobacteria. These results suggest that BCG vaccination of dairy calves in a natural transmission setting confers variable protection to animals against bTB in a high prevalence area.

EPPO Datasheet: Naupactus xanthographus

EPPO Datasheet: <i>Naupactus xanthographus</i>

Local and regional sources of organochlorine pesticides in a rural zone in central Chile

There is a lack of knowledge about exposure to airborne organochlorinated pesticides (OCPs), especially for people living near agricultural zones in developing countries. This study is the first one to measure spatiotemporal variation of airborne OCPs within a major agriculture area in Central Chile. Polyurethane foam passive air samplers (PUF-PAS) were deployed in five sites in the town of Molina (35°7′S, 71°17′W) and another one in the nearby town of Lontué (35°3′S, 71°17′W). Samplers were deployed from August 2016 to January 2018, in 8 periods lasting 2–3 months each. The measured concentrations in air (pg m−3) as geometric mean were α-HCH: 0.59, γ-HCH: 3.8, o,p'-DDT: 1.3, p,p'-DDT: 2.0, o,p'-DDE: 0.52, p,p'-DDE: 5.5, o,p'-DDD: 0.26, p,p'-DDD: 0.64, PeCB: 29.1 and HCB: 14.5. The highest concentrations were measured in the warmer months and negative correlations (p < 0.05) between the log of the concentrations and the inverse of ambient temperature were found, suggesting soil volatilization as the main release process. The exceptions were o,p'-DDE, p,p'-DDE and HCB. In the case of HCB, waste burning was a likely source. Most OCP concentrations showed significant spatial heterogeneity (p < 0.05), suggesting local source contributions are dominant; the exceptions are α-HCH and PeCB (p > 0.05) whose concentrations depend on regional sources. Backward wind trajectories obtained using NOAA's HYSPLIT identified air masses coming from the south and southwest when ambient concentrations are highest; these regional sources contribute to all ambient OCP concentrations.

Signals of Surface Deformation Areas in Central Chile, Related to Seismic Activity—Using the Persistent Scatterer Method and GIS

Interferometric synthetic aperture radar is an effective means of measuring changes in the altitude of the Earth’s surface. In this research, the areas of surface deformation associated with low- and medium-intensity seismic events in Central Chile were analyzed using SENTINEL 1 satellite radar interferograms and geographical information system (GIS) tools. The persistent scatterer method was used to reduce noise from conventional InSAR methods. The results revealed that the coastal zone of Central Chile has a high density of daily earthquakes with a prevalence (93.03%) of low- and medium-intensity earthquakes. Monthly deformation maps were developed for the coast of the Biobio region in Central Chile. A clear deformation pattern is defined along the coast, being greater in the Arauco, Lota and Lebu areas. It was also shown that there was a slight upward trend in the north and northeast zone (i.e., δup ~3 mm/year), while there was an obvious accentuated upward trend (i.e., δup ~24 mm/year) in the southern part. This movement increases as latitude increases. This pattern is related to the daily seismic activity, the product of the movement between plates, and the geological faults located in the area. The deformation and trend maps provide certainty in terms of where hotspots are located, e.g., the most hazardous areas in the study zone, which can be applied to urban planning and/or safety assessment.

Multicompartmental analysis of POPs and PAHs in Concepciόn Bay, central Chile: Part I – Levels and patterns after the 2010 tsunami

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) were determined in abiotic samples from Concepción Bay in Central Chile. Samples were soxhlet extracted and injected in gas chromatography–mass spectrometry (GCMS). Polybrominated diphenyl ethers (PBDEs) showed the highest levels in air (3–1100 pg m−3), in water (2–64 pg L−1), in sediment, and soil (1–78 ng g−1 (dw)). PAHs were also high in the air (1–6 ng m−3), in water (1–7 ng L−1), in sediment (90–300 ng g−1 (dw)), and in soil (15–2300 ng g−1 (dw)). The polychlorinated biphenyls (PCBs) and chlorinated pesticides were generally low and did not show clear trends along the water column, with exception of PAHs. New data are presented in this work to assess the health status of a relevant coastal area in central Chile.

Air Pollution and Cardiorespiratory Changes in Older Adults Living in a Polluted Area in Central Chile.

One recognized cause of cardiorespiratory diseases is air pollution. Older adults (OA) are one of the most vulnerable groups that suffer from its adverse effects. The objective of the study was to analyze the association between exposure to air pollution and changes in cardiorespiratory variables in OA. Observational prospective cohort study. Health questionnaires, blood pressure (BP) measurements, lung functions, respiratory symptoms, physical activity levels, and physical fitness in high and low exposure to air pollution were all methods used in evaluating OAs in communes with high contamination rates. Linear and logistic models were created to adjust for variables of interest. A total of 92 OA participated in this study. 73.9% of the subjects were women with 72.3 ± 5.6 years. 46.7% were obese, while 12.1% consumed tobacco. The most prevalent diseases found were hypertension, diabetes, and cardiovascular disease. Adjusted linear models maintained an increase for systolic BP of 6.77 mmHg (95% CI: 1.04-12.51), and diastolic of 3.51 mmHg (95% CI: 0.72-6.29), during the period of high exposure to air pollution. The adjusted logistic regression model indicated that, during the period of high exposure to air pollution increase the respiratory symptoms 4 times more (OR: 4.43, 95% CI: 2.07-10.04) in the OA. The results are consistent with an adverse effect on cardiorespiratory variables in periods of high exposure to air pollution in the OA population.

Land cover and potential for tsunami evacuation in rapidly growing urban areas. The case of Boca Sur (San Pedro de la Paz, Chile)

The destructive potential of a massive tsunami is not only related to society's response capacity and evacuation plans, but also to the urban morphology and land cover. The Boca Sur neighborhood is one of the areas in central Chile that is most exposed to tsunamis, and it is framed in the context of increasing urban growth. Faced with the worst tsunami scenario (earthquake Mw = 9.0), residents' evacuation potential is analyzed by using a least-cost-distance model, and two scenarios of land cover change are considered (2002 and 2018). Presently, the sector's urban areas have grown by 83%, therefore its population has also grown. The evacuation times consider an average walking speed (1.22 m/s) for both years (2002 and 2018). This analysis establishes that over 40% of the study area is more than 60 min away from the safe zones established by authorities. This differs greatly from the 22-min average tsunami arrival time. Moreover, 19% of the area could not be evacuated in less than 30 min. Therefore, it can be concluded that the increased urbanization in the coastal area has not improved travel times, as urban planning did not consider the optimization of evacuation times to the designated safe zones. In this study, we propose new safe zones that would help reducing evacuation times to 30 min. In addition to the area's high tsunami risk, the evacuated population's strong travel time limitations are added, prioritizing the incorporation of social and urban resilience elements that help to effectively reduce the risk of disaster, by using land-use planning and community work.

Data-based wildfire risk model for Mediterranean ecosystems – case study of the Concepción metropolitan area in central Chile

Abstract. Wildfire risk is latent in Chilean metropolitan areas characterized by the strong presence of wildland–urban interfaces (WUIs). The Concepción metropolitan area (CMA) constitutes one of the most representative samples of that dynamic. The wildfire risk in the CMA was addressed by establishing a model of five categories (near zero, low, moderate, high, and very high) that represent discernible thresholds in fire occurrence, using geospatial data and satellite images describing anthropic–biophysical factors that trigger fires. Those were used to deliver a model of fire hazard using machine learning algorithms, including principal component analysis and Kohonen self-organizing maps in two experimental scenarios: only native forest and only forestry plantation. The model was validated using fire hotspots obtained from the forestry government organization. The results indicated that 12.3 % of the CMA's surface area has a high and very high risk of a forest fire, 29.4 % has a moderate risk, and 58.3 % has a low and very low risk. Lastly, the observed main drivers that have deepened this risk were discussed: first, the evident proximity between the increasing urban areas with exotic forestry plantations and, second, climate change that threatens triggering more severe and large wildfires because of human activities.

First report of Eutypa lata causing cankers and dieback in sweet cherry in Chile.

Sweet cherry (Prunus avium) is one the most important fruit crops in Chile. Its production has significantly grown in recent years, reaching 228,448 tons exported in 2019/2020, to 47 countries. One of the main threats for this expanding crop are fungal pathogens, especially those that cause wood diseases. Cherry orchards (n=35) located in the central area of Chile, from Curicó (34°58'58''S 71°14.366'W) to Angol (37°47'42.7''S 72°42.982'W), were surveyed during 2020. Wood samples were collected (n= 72) from living branches and trunks showing dieback, cankers and dark necrosis, mostly wedge shaped. Small wood sections (0.5-cm) were cut off from the margin of the necrosis and surface disinfected using 0.5% v/v sodium hypochlorite. Sections were plated on a quarter-strength potato dextrose agar amended with 1mg/L tetracycline (PDA-tet). Plates were incubated at 25°C until mycelial development and subsequently the isolates were purified transferring excised fungal tips to PDA. Colonies (n=21) developed white cottony mycelia, which turned slightly greyish and flatter after 10-days at 25°C. Isolates developed black pycnidia which released beige conidial matrixes after subsequent 15-days at 25 +/-2°C and 12-h photoperiod. Conidia were hyaline, curved and filiform, measuring 19.8-(27.9)-36.7 μm length (lineal) x 1.2-(1.7)-1.9 μm width (n=70), according to Eutypa lata (Rappaz, 1984). DNA was extracted from mycelia of the representative isolates HMCe30a, HMCe41a, HMCe109c and HMCe110a. The partial β-tubulin gene was amplified using bt2A/bt2B primers (Glass & Donaldson 1995) and the internal transcribed spacer region was amplified using ITS1/ITS4 primers (White et al. 1990). Sequences were BLAST analyzed, finding that ITS shared 99% and βTUB 100% identity with E. lata strain CBS 208.87 (Rolshausen et al. 2006). Sequences were accessioned to GenBank (MW363035, MW363034, MW363033 and MW363032 [ITS], and MW366820, MW366819, MW366818and MW366817 [βTUB]). The isolates were inoculated on sweet cherry healthy plants cv. Kordia, produced by rooting scions in tap water amended with 500 ppm of indole-butyric acid, for 30 days. An injury was made in the upper third of the shoot using a sterile 0.5-cm diameter corkborer. Mycelial plugs were placed on the injuries and covered with plastic film, using sterile agar for controls (n=25). Plants were incubated in aerated tap water for 60 days at 23 +/-3 °C. After incubation, plants were cut exposing dark-brown necrotic lesions, while control plants remained asymptomatic. Moreover, 2-year old potted plants cv. Lapins were inoculated (n=3 per isolate) with mycelial plugs, on fresh cuts of their main lateral branches, in January 20th, and remained under partial shade for 72-days. After incubation, bark was removed from inoculated branches and the necrotic lesions length was measured. HMCe109c was the most virulent isolate (3.6 cm), followed by HMCe30a (2.1 cm), HMCe41a (1.9 cm) and HMCe110a (1.1 cm), while symptoms were not reproduced in controls. Fulfilling Koch's postulates, fungi were reisolated from all inoculated plants in both pathogenicity tests and no fungus was recovered from controls. To our knowledge this is the first report of Eutypa lata causing wood decay in sweet cherry in Chile. The pathogen was recently reported causing dieback of grapevines in Chile (Lolas et al. 2020). These are significant findings due to the frequent proximity of sweet cherry orchards and vineyards, which facilitates cross infections.

First report of Seimatosporium vitifusiforme causing trunk disease in Chilean grapevines (Vitis vinifera).

Grapevine is one of the most important fruit crops in Chile and trunk diseases reduce the productivity, quality, and longevity of the vineyards. A survey was conducted in ancient (> 50 years) vineyards of Cauquenes (35°57´14´´S 72°17´07´´W) and Itata valleys (36°38´13´´S 72°30´57´´W), located in the central area of Chile, during 2019. Trunks and cordons showing dieback and dark brown to black wood discoloration were collected from 50 to 200-year-old plants of six cultivars: País, Moscatel, Torontel Amarilla, Carignan, Aliatica and Aligote. The bark was removed and 0.5-cm sections were cut from the edges of necrotic wood lesions. Subsequently, pieces were surface disinfected using 10% v/v sodium hypochlorite bleach (4.9% chlorine), plated on acidified quarter-strength potato dextrose agar (APDA) (25% PDA, acidified with 0.1% v/v 85% lactic acid) and incubated at 25°C, for 14 to 28 days. Hyphal tips were excised and transferred to PDA to obtain pure cultures. Along with the conidiomata and conidia produced, growth rate, color and shape of the colonies on PDA, after 7 and 14 days of incubation at 25°C (n=17), were recorded. DNA was extracted from pure cultures of three isolates on PDA: HMV3, HMV64 and HMV81. The internal transcribed spacer region and partial β-tubulin genes were amplified, using ITS1/ITS4 (White et al. 1990) and bt2A/bt2B (Glass & Donaldson 1995) primers, respectively. Sequences were subjected to NCBI BLAST search and compared to the published sequences. Isolated colonies were whitish to light-brown, cottony with a smooth margin (n=37). Their mycelium grew 1.9 cm after 7-days and 3.2 cm after 14-days of incubation on PDA, at 25°C. Colonies produced black globose pycnidia and curved, slightly-pigmentated, three-septated conidia 22.3-(29.8)-32.2 x 3.9-(4.8)-5.3 µm (n=30), with apical and basal flexuous appendages 4.3-(12.7)-21.5 µm (n=20). When compared to type sequences of Seimatosporium vitifusiforme (Lawrence et al. 2018), ITS and βtub sequences identity of these isolates were 99 to 100% identical. To produce uniform healthy plants for pathogenicity tests, Petit Syrah canes (1-year old) were rooted in tap water amended with 500 ppm of indole-butyric acid, for 30 days. Plants were inoculated with 0.5-cm diameter mycelial plugs of actively growing colonies of the isolates HMV3, HMV64 and HMV81 (GenBank accessions no. MW026664, MW048518; MW026665, MW048519, and MW026666, MW048520, respectively). Sterile agar plugs were used for controls. Five plants per pathogen isolate were incubated at 25°C, in a humid chamber, for 25 days, and seven additional plants per isolate were incubated in aerated tap water, for 55 days. After the incubation period, the bark was removed and the lesions were measured. Dark necrotic lesions identical to the original observations were reproduced, both in the high humidity chamber (6% length) and water (10% length). There were no differences in lesion length among the isolates (P < 0.05). Control vines remained asymptomatic. To fulfill Koch´s postulates, isolations were made from symptomatic vines and compared to the ones used for inoculation, and found to be identical. Seimatosporium vitifusiforme was previously reported as a pathogen of Vitis vinifera in California, USA (Lawrence et al. 2018). Consequently, this is the second report of this fungus as a grapevine pathogen and the first one affecting Latin-American grapevines.

Identification and Pathogenicity of Diplodia, Neofusicoccum, Cadophora, and Diaporthe Species Associated with Cordon Dieback in Kiwifruit cultivar Hayward in Central Chile.

Dieback symptoms associated with fungal trunk pathogens cause significant economic losses for farmers of kiwifruit and other woody fruit trees worldwide. This study represents the first attempt to identify and characterize the fungal trunk pathogens associated with cordon dieback disease of kiwifruit in central Chile. Field surveys were conducted throughout the main kiwifruit-growing regions in central Chile to determine the incidence and characterize the fungal trunk pathogens associated with cordon dieback of kiwifruit cultivar Hayward through morphological, molecular, and pathogenicity studies. A total of 250 cordon samples were collected and isolations were performed on 2% acidified potato dextrose agar (APDA) plus antibiotics and Igepal. The incidence of kiwifruit cordon dieback ranged between 5% and 85% in all surveyed areas in central Chile. A total of 246 isolates were isolated and identified using culture and morphological features belonging to three fungal taxa: Diaporthaceae spp. (Diaporthe ambigua and D. australafricana; n = 133 isolates); Botryosphaeriaceae spp. (Diplodia seriata and Neofusicoccum parvum; n = 89 isolates); and Ploettnerulaceae spp. (Cadophora luteo-olivacea and C. malorum; n = 24 isolates). These were identified using phylogenetics studies of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of the rDNA, part of the β-tubulin gene (tub2), and part of the translation elongation factor 1-α gene (tef1-α). Isolates of N. parvum and D. seriata were the most virulent, causing internal brown lesions and dieback symptoms in attached green shoots, attached lignified canes, and young inoculated kiwifruits. This report is the first to describe D. seriata and C. luteo-olivacea associated with kiwifruit cordon dieback in Chile. It presents the first description of N. parvum causing kiwifruit dieback worldwide.

ASSESSING THE DAMAGE OF FORESTS BURNT IN CENTRAL CHILE BY RELATING INDEX-DERIVED DIFFERENCES TO FIELD DATA

Abstract. To assess the damage produced by wildfires on forest ecosystems is a critical task for their subsequent management and ecological restoration. Satellite-based optical images provide reliable ex-ante and ex-post data about vegetation state, making them suitable for the aforementioned purpose. In this study we assessed the damage produced on two forested lands by the series of wildfires occurred in central Chile during summer 2017. Arithmetic differences from pre- and post-fire NDVI (normalized difference vegetation index), NDWI (normalized difference water index) and NBR (normalized burnt ratio) were retrieved from a Sentinel-2 image set embracing four near-anniversary summer dates: 2016 (ex-ante), 2017, 2018 and 2019 (ex-post). The nine index-derived differences resulting were correlated to CBI (composite burn index) data collected in the field during summer 2019, and a model constructed by a stepwise regression was formulated. Results show that planted forests exhibited a somewhat smaller biomass recovery than native ones, in part due to their post-fire clearing and preparation, deriving in a smaller tree cover. CBI poorly performed because its calculation includes low vegetation strata largely recovered at the time of the field data collection. However, when overstory field data were used alone correlations noticeably increased (r = 0.66–0.74). This was because during the field campaign this stratum was still appreciably damaged, thus better matching with the data provided by the indices-derived differences, intrinsically more representative of uppermost vegetation layers. The burn damage was mapped on both study areas employing the best performing regression model, based on NDWI2016-2019, NDWI2016-2017, NBR2016-2018 and NBR2016-2017 differences (adjusted R2 = 0.72, p &lt; 0.005, root mean square error = 0.38). The use of approaches like this one in other areas of central Chile, where wildfires are increasing their frequency and intensity, might contribute to better lead post-fire management and restoration actions on their damaged forest ecosystems.

Environmental variables determining the distribution of an avian parasite: the case of the Philornis torquans complex in South America.

Philornis flies are the major cause of myiasis in nestlings of Neotropical birds, being of major concern in geographically-restricted and endangered bird species. Despite its relevance for the conservation of birds, there is little information about the environmental dimensions determining Philornis spp. geographical range. By using maximum entropy, we identified for the first time the macro-environmental variables constraining the abiotic niche of the P. torquans complex in South America, and provided a model map of its potential distribution based on environmental suitability. We identified the minimum temperature of the coldest month as the most relevant variable, associated with the largest decrease in habitat suitability in Brazil and northern South America. Furthermore, the mean temperature of the warmest quarter limited suitability mostly along with the Andean range. In addition, humidity and moisture are influential factors in most of Argentina, northern Chile, and coastal Peru. The geographical projection suggests that environments in most of central-eastern Argentina, and in a broad area in central Chile, are suitable for the presence of the P. torquans complex. Besides providing information about the ecology of Philornis spp., this study represents a tool for bird conservation and a reference for future work on the distribution of this genus.

Use of environmental isotopes to assess groundwater pollution caused by agricultural activities

ABSTRACT This work applied environmental isotope techniques to validate the results of previous studies on recharge sources in a rural area in central Chile (34.3° S and 71.3° W) and discern the origin of nitrate contamination in wells. Stream water and groundwater samples were taken during three surveys, two during spring snowmelt and one in low-water conditions. Chemical analyses included major cations and anions, isotope analyses included 18O-H2O; 2H-H20; 3H-H20; 18O-NO3 − and 15N-NO3 −. The stable isotope data show that surface water and deep groundwater present depleted isotope values associated with recharge from the Andes Mountains and that shallow groundwater has more enriched isotope values that reflect the contribution of local recharge from rainwater infiltration. Depleted isotope values observed in shallow groundwater show the effect of recirculated river water used for irrigation. These results are consistent with the conceptual groundwater model developed in previous studies. Some wells have nitrate concentrations above the allowable limit for drinking water. The stable nitrogen isotopes indicate that nitrate is associated mainly with urea and ammoniacal fertilizers, and nitrate is attenuated by denitrification. The results of this study are relevant to improving management of groundwater resources used for drinking water.

Cupressus macrocarpa leaves for biomonitoring the environmental impact of an industrial complex: The case of Puchuncaví-Ventanas in Chile

The Punchuncaví Valley is one of the most polluted areas in central Chile affected by anthropogenic emissions from the Ventanas Industrial Complex (IC) where the most important industry is the copper smelter and refinery. In this context, this research aims were to assess the usefulness of the Cupressus macrocarpa as a biomonitor. The leaf samples were taken from five selected sites, located between 0.8 and 15 km away from the source. A total of 34 elements were analyzed in leaf samples by ICP-MS and examined by enrichment factor (EF), hierarchical cluster analysis (HCA), and principal component analysis (PCA). Leaf concentration of As, Ca, Cd, Cu, Dy, Er, Gd, K, Li, Mg, Mn, Mo, Na, Nd, P, Pb, Pr, S, Sb, Sr, Ti, Yb and Zn showed statistically significant differences between sampling sites (p-value < 0.05). A clear trend to increase the concentration of Cu, Sb, S, As, Cd and Pb with the proximity to the IC. Besides, high values of Cu (93.4–369 mg kg−1) and As (7.6–12.7 mg kg−1) were observed near to industrial area exceed the phytotoxic levels reported in plants with EF > 3000% for Cu and >1300% for As. The application of PCA and HCA identified 6 factors related to the industrial complex, traffic and geogenic sources, providing the greatest variance the component related to industrial activity mainly with copper smelter and refinery. According to the results, the C. macrocarpa leaves are a good biomonitor to evaluate the high pollution load for anthropogenic elements in industrial areas.

External and gastrointestinal parasites of the Franklin’s Gull, Leucophaeus pipixcan (Charadriiformes: Laridae), in Talcahuano, central Chile

Parasitological studies of the Franklin's gull, Leucophaeus pipixcan, are scarce, and knowledge about its endoparasites is quite limited. In order to describe its parasitic community, a total of 60 Franklin's gulls were captured in the coastal area in central Chile, using modified Bal-chatri traps. Ectoparasites were collected from all 60 live individuals through inspection of their plumage, while 30 were examined for endoparasites by standard parasitological necropsy. The prevalence of ectoparasites was 78.3%, including the feather mite Zachvatkinia larica (43.3%) and four species of lice: Actornithophilus piceus lari (15.0%), Austromenopon transversum (6.7%), Quadraceps punctatus (10.0%) and Saemundssonia lari (46.7%). Some 25 of 30 (83.3%) of birds necropsied were parasitized with the following helminths: Aporchis sp. (6.7%), Tetrabothrius cylindraceus (56.7%), Cyclophyllidea gen. sp. (3.3%), Profilicollis altmani (56.7%), Eucoleus contortus (10.0%), Cosmocephalus obvelatus (13.3%), Paracuaria adunca (10.0%), Stegophorus sp. (3.3%) and Tetrameres skrjabini (3.3%). To our knowledge, with the exception of P. altmani, these helminths are reported for first time in the Franklin's gull.

Vulnerable areas determination based on seismic response at Chile center region

Chile is one of most seismic countries in the world. In the past 100 years, more than 8 major seismic events occurred in Chile, with the coastal area of central Chile being one of the most affected Since 2007, nearly 2,306 earthquakes were recorded in this area with magnitudes varying between 1.9 and 6.9 in the Ritcher and Mercalli scales. The earthquakes’ impact on the engineering structures depends on several factors, such as: the depth of the wave, wave type, geomorphological aspects of the rock, and soil properties. Chile central region of is a very important economics area, but at the same time, very vulnerable. The cities existing on this area, are installed in coastal plains, limited by Coastal Mountains and Pacific Ocean. Most of the seismic activity episodes recorded by Nacional Seismological center (CSN) is on the ocean. The present research aims to identify the regions vulnerable to significant seismic activities based on the average shear wave velocity on the upper 30m (Vs30) and using Geographic Information Systems. The Vs30 values were measured by the United Stated Geological Service (USGS). This analysis is based on the topography, geological units classified by Chilean norms NCh433, NCh2369, and law decree 61/ 2011. The analysis indicated that last epicenter city, Cobquecura, is the low vulnerable area, considering high Vs30 values and low number of habitants. Cities as Concepción, Talcachuano, San Pedro de la Paz, Coronel y Hualpén are more vulnerable because low Vs30 values, and high population. This factor can be associated to river mouths and floodplains presents in this area.