Métodos de análisis foliar aplicados bosques naturales y exóticos de interés comercial: características, ventajas y desventajas.

El presente trabajo, corresponde a una síntesis bibliográfica cuyo objetivo radica en la descripción de las principales características de tres de los métodos más utilizados en los análisis de tejido foliar de origen vegetal. Para ello, se analizaron los estudios relacionados  la temática expuesta, desde los cuales se extrajeron los principales resultados y discusiones sobre las ventajas del uso de cada uno de ellos. Los métodos aquí presentados corresponden al método de los valores críticos (VC), método DRIS (diagnosis and recommendation integrated system), y método a través del análisis de vectores. Las principales conclusiones indican que los tres métodos permiten abordar en general las distintas condiciones en las cuales crecen los bosques naturales y exóticos de interés comercial, no destacándose ningún método sobre otro, sin embargo, cada uno posee sus ventajas dependiendo de la especie tratada y el sitio. Lo anterior permite su recomendación con base a características de la especie analizada y las condiciones de sitio en las cuales crece y se desarrollan las especies forestales. Palabras clave: foliar, macro-elementos, micro-elemento

Benthic macroinvertebrate communities in Salado and Loa Rivers, Antofagasta Region, Chile

The Loa River is the longest Chilean river with 440 km, located in the Atacama Desert. It has three tributaries’ rivers, and its fauna has been poorly studied, due to mainly access difficulties. The aim of the present study was the first characterization of benthic invertebrate community structure in a confluence of Loa and Salado rivers considering the derive invertebrates and benthic communities. The results revealed that species composition in benthic samples has no significant differences between Salado and Loa rivers before the confluence with Salado River, but both sites had significantly high species numbers in comparison to Loa River in Calama after Salado confluence whereas in derive species composition did not have species differences. Finally, the results of null models revealed that species number for three sites had no structured pattern for benthic and derive samples. Ecological and biogeographical topics were discussed here

Análisis de cambio de cobertura y uso de suelo en una subcuenca preandina chilena. Herramienta para la sustentabilidad productiva de un territorio

Se analizó la dinámica de cambio de cobertura y uso de suelo para una subcuenca hidrográfica, región de La Araucanía, Chile, periodo 1994-2007. El área registra cambios en la cobertura del suelo, intensa división predial y degradación de los sistemas naturales. La metodología comprendió (1) análisis cartográfico, matriz de confusión e índice de kappa y (2) análisis/cuantificación de cambios mediante matriz de cambio. Los resultados permitieron identificar áreas sometidas a mayor presión de uso, identificándose las categorías “cultivos-praderas naturales” y “plantaciones forestales” como las coberturas que concentran el 79,5% de la superficie total del cambio neto en el área, con tasa de ganancia de superficie de uso forestal con especies exóticas de 432 ha año-1 en desmedro de suelos de uso agropecuario. Nuestros resultados reafirman la necesidad de analizar la evolución en el uso del suelo previo a la identificación de las potencialidades del recurso suelo para soportar nuevas actividades productivas

A preliminary study of chemical properties in temperate forest fire of the Chilean Andean range for planning of ecosystems restoration

Despite vegetation in fire-prone landscapes having different fire adaptations, a change in the worldwide fire regime could affect all ecosystem processes and systems. In this sense, soil systems play a key role in ecosystems, not only providing inorganic nutrients to plants, but also serve as filter water and carbon storage. The aim of this research was to identify the effects of wildfire on the chemical properties of young volcanic soils over the medium-term in two natural protected areas of Andean Mountain range. A comparative statistical analysis was performed to identify significant differences in different soil parameters between forty-eight unburned and burned soil samples. Therefore, significant differences were identified between evaluated samples in organic matter, macronutrients, micronutrients, and cation exchange capacity. Whilst organic soil matter and potassium content substantially increased due to incomplete vegetation combustion; the presence of calcium content and cation exchange capacity decreased with the occurrence of fire. Our findings showed that there were significant differences between unburned soils or a soil that had been burned once and soil that had been burned twice in thirteen years. These findings should support decision making, improving the selection of passive or active restoration actions and thus efficiency in forest management

Hybrid identification in Nothofagus subgenus using high resolution melting with ITS and trnL approach

The genus Nothofagus is the main component of southern South American temperate forests. The 40 Nothofagus species, evergreen and deciduous, and some natural hybrids are spread among Central and Southern Chile, Argentina, New Zealand, Australia, New Guinea and New Caledonia. Nothofagus nervosa, Nothofagus obliqua and Nothofagus dombeyi are potentially very important timber producers due to their high wood quality and relative fast growth; however, indiscriminate logging has degraded vast areas the Chilean forest causing a serious state of deterioration of their genetic resource. The South of Chile has a large area covered by secondary forests of Nothofagus dombeyi. These forests have a high diversity of species, large amount of biomass and high silvicultural potential. This work shows a case of hybrid identification in Nothofagus subgenus in different secondary forests of Chile, using high resolution melting. Unknown samples of Nothofagus subgenus are genetically distinguishable with the ITS region of Nothofagus antarctica, Nothofagus nitida and N. obliqua species. It was not possible to distinguish between unknown samples of Andean versus coastal origin. Melting curves with ITS approach of unknown material are genetically similar, positioned between N. dombeyi and N. antarctica and distant from N. nitida. The unknown samples are genetically very close to Nothofagus dombeyi. This suggests the presence of hybrid individuality between species (N. dombeyi × N. antarctica) with the possibility of introgression towards the gene pool of N. antarctica, producing the deciduous foliage that is both present. The trnL locus has no distinction between the N. dombeyi and N. antarctica species, since a similar melting curve is present and equal Tm (80.00 °C). The trnL locus cannot be genetically distinguished from one unknown sample of Nothofagus to another, as highlighted in this study

Relationship between salt use in fish farms and driftof macroinvertebrates in a freshwater stream

In Chile, salt (NaCl) use per salmon fish farm ranges between 20-30 t yr(-1) and is used to prevent and control fungal infections. An increase in salinity in freshwater can have adverse effects on freshwater biodiversity and ecosystem functions and services. We studied the effects of fish-farm effluents on benthic macroinvertebrate communities in a northern Patagonian stream (Chile). Benthic samples were collected at 3 sites near a land-based salmon aquaculture facility (one located 100 m upstream from the fish-farm outlet for effluent, 2 sites located 200 and 400 m downstream from the effluent source). We found changes in benthic macroinvertebrate communities downstream from the effluent, with higher abundances of tolerant taxa and lower abundances of sensitive taxa, which was related to nutrient and salt concentration in the water. We also studied the effects of salinity on macroinvertebrate drift in a mesocosm experiment conducted in recirculating channels, measuring the drift of 2 salt-sensitive macroinvertebrates (Andesiops peruvianus and Smicridea annulicornis), collected from an unpolluted northern Patagonian stream, after exposure to a range of salinity concentration pulses similar to those from fish farms. Our results demonstrate that (1) fish-farm effluent can alter stream macroinvertebrate community composition and dynamics, and (2) such effects are at least partly driven by high salt concentrations in effluent waters.We thank the vice rectory for research and postgraduate studies at the Catholic University of Temuco and project MECESUP UCT 0804. The study was funded by the Fondecyt project 'Tracing organic pollution from land-based aquaculture systems in terms of fluorescence spectroscopy and assessment of ecotoxicological biomarkers in aquatic organisms in Southern Chile' (Ref. 1130132). L.B. was supported by the Spanish Ministry for Science, Innovation and Universities funds (Ref. RTI2018095023-B-I00) and Basque Government funds (Ref. IT95116) to the UPV/EHU Stream Ecology Group. Editoria

Environmental Determinants of COVID 19 Transmission Across a Wide Climatic Gradient in Chile

Several studies have examined the transmission dynamics of the novel COVID-19 disease in different parts of the world. Some have reported relationships with various environmental variables, suggesting that spread of the disease is enhanced in colder and drier climates. However, evidence is still scarce and mostly limited to a few countries, particularly from Asia. We examined the potential role of multiple environmental variables in COVID-19 infection rate [measured as mean relative infection rate = (number of infected inhabitants per week / total population) × 100.000) from February 23 to August 16, 2020 across 360 cities of Chile. Chile has a large climatic gradient (≈ 40º of latitude, ≈ 4000 m of altitude and 5 climatic zones, from desert to tundra), but all cities share their social behaviour patterns and regulations. Our results indicated that COVID-19 transmission in Chile was mostly related to three main climatic factors (minimum temperature, atmospheric pressure and relative humidity). Transmission was greater in colder and drier cities and when atmospheric pressure was lower. The results of this study support some previous findings about the main climatic determinants of COVID-19 transmission, which may be useful for decision-making and management of the disease.Funding was provided by the Initiation Fondecyt project 11170390 to F.C.A. D.N. received a CONICYT-PFCHA/ Doctorado Nacional/2019-21191862 scholarship. A.C. received a scholarship of the National Secretariat of Science, Technology and Innovation (SENACYT, Panama) and by the National Research System of Panama (SNI; doctoral student category)

Spectral characterization of didymosphenia geminata under laboratory conditions: Bases for a monitoring and early warning system in river systems of south Central Chile

The effects of climate change and the severe anthropization of local river systems have contributed to the alteration of ecological processes, affecting the water quality in these systems and thus generating conditions for the emergence of algal species. In this context, the object of the present study was to evaluate the potential of remote detection techniques to obtain a spectral characterization of D. geminata under controlled laboratory conditions. This would provide the basic information for the design and implementation of a monitoring and early warning system. D. geminata cells obtained from two southern Chilean river systems were cultivated in the laboratory and analysed using hyperspectral techniques to construct their spectral signatures. The results showed the feasibility of distinguishing between the presence and absence of D. geminata when it occurs in association with other diatom present in the environmental. The results could be the first step towards the design and implementation of a monitoring and early warning system to facilitate existing inspection activitie

Botánica Forense en Chile: El caso de Aristotelia chilensis (Molina) Stuntz y su potencial utilidad como especie bioindicadora forense

Aristotelia chilensis is mentioned for the first time for plants grown on pig carcasses decomposing. Its potential as a bioindicator species for the development of forensic botany in Chile and its importance in the reconstruction of criminal events are discussed

Composição proximal e perfil de ácidos graxos de Hemigrapsus crenulatus (H. Milne Edwards, 1837) como um dos principais alimentos da “blenny patagônica” Eleginops maclovinus (Cuvier, 1830)

The Patagonian blenny (Eleginops maclovinus) is species endemic to South America with physiological characteristics that would facilitate its incorporation into Chilean aquaculture. However, there is currently no specific artificial food that can be used to raise E. maclovinus. In light of this problem, this study describes the proximal composition and fatty acid profile of the crab Hemigrapsus crenulatus, one of the main foods of E. maclovinus. The purpose of the study is to serve as basic information for the development of a specific artificial diet for juveniles of this fish species. The proximal analysis of the complete body of H. crenulatus indicates that it is mainly composed of ash (35.9%), proteins (32.2%), glucides (19.8%) and minor lipids (3.6%). The fatty acid profile is 40.7% PUFAs, 29.7% MUFAs and 29.5% SAFAs, and the most abundant acids are Eicosapentaenoic (18.8%), Oleic (6.8%) and Palmitic (16.6%), respectively. H. crenulatus has highest level of proteins, lipids and PUFAs among the species of the Brachyura infraorder