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Agricultural land covers approximately 40% of Earth’s land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM composition change and DON concentration increase differed among climate zones and could be related to the intensity of current and historical nitrogen fertilizer use. As a result of agriculture intensification, increased DON concentrations and a more microbial-like DOM composition likely will enhance the reactivity of catchment DOM emissions, thereby fuelling the biogeochemical processing in fluvial networks and resulting in higher ecosystem productivity and CO 2 outgassing.

Easy, economic, precise species authentication is currently necessary in many areas of research and diagnosis in molecular biology applied to conservation studies of endangered species. Here, we present a new method for the identification of three fox species of the Lycalopex genus in Chile. We developed an assay based on high‐resolution melt analysis of the mitochondrial cytochrome B gene, allowing a simple, low cost, fast, and accurate species determination. To validate the assay applicability for noninvasive samples, we collected fecal samples in the Atacama Desert, finding unexpectedly one species outside of its known distribution range. We conclude that the assay has a potential to become a valuable tool for a standardized genetic monitoring of the Lycalopex species in Chile. The mitochondrial cytochrome B gene DNA barcode coupled with the high‐resolution melting method to foxes taxonomic identification of the genus Lycalopex. This technique recognized the three species of Lycalopex present in Chile.

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.

The kodkod (Leopardus guigna) is a small felid dependent on forests. We studied the activity patterns of this felid during two years in a periurban protected area. We also compared its overlap with rodents and birds. During the first year, we detected it to be mainly nocturnal. In the second year, a non-significant diurnal activity was observed. During the first year overlap was higher with rodents, and lower with birds, but this reversed during the second year.

In accordance with the Sustainable Development Goals of the United Nations, the Environmental Impact Assessment (EIA) is the main management tool used to identify and prevent the impact of productive activities on the environment and human health and promote compensation measures. Metallic mining is the main productive sector in Chile. In 2021, Chile was the highest global producer of copper, the second-highest producer of molybdenum, and the third-highest producer of silver. Other types of non-metallic mining, such as siliceous aggregates, iodine, and hydrocarbons, are also notable. Mining activity requires robust and flexible environmental legislation. This paper analyzes the performance of the Chilean EIA system regarding mining projects entered into the system as Environmental Impact Declarations (EIDs) for low-incident projects and Environmental Impact Studies (EISs) for high-incident projects. The 2867 mining projects submitted to the Chilean EIA system as EIDs (91.8%) and EISs (8.2%) between 1994 and 2019 were compiled. For a proper performance evaluation, a representative sample of 68 projects (61 EID and 7 EIS) was studied through a principal coordinate analysis using eleven indicators widely used in the EIA scientific literature. The results do not show significant differences between the EID and EIS projects or remarkable differences regarding the increasing restrictions introduced by the successive regulatory periods SD30, SD95, and SD40. Based on the observed weaknesses, four opportunities for improvement are proposed focused on creating a simplified sanctioning procedure, upgrading the form of delivery of the project monitoring information, early citizen participation, and incorporating the climate change variable into the projects. This paper extends the methodology introduced in previous papers to evaluate the performance of the Chilean EIA system in mining projects, seeking also to offer a feasible methodology to other countries with a similar socio-economic context or other productive sectors potentially impacted by the degradation of land and renewable natural resources.

The increasing industrial pulp production has led to a negative growth of the associated solid wastes, thus making necessary alternative ways of handling them in suitable sanitary landfills to minimize adverse effects on the environment and well-being of people. Solid waste treatment prior to its disposal is a target to minimize pollution of the natural resources (air, soil, water) due to accidental leaching. This paper aims to determine better experimental conditions in the container to develop an optimal composting design for pulp solid wastes. For this, an experimental methodology is introduced. This paper presents the results about the influence of independent control variables (grits addition and composting process time) on dependent variables (chemical and biological), for which a composting design was used, and a face-centered central composite factor was applied. The results showed mature compost over 60-day treatment, with the following experimental observations (i) the grits addition did not decrease the pH in the first stage of the composting process; and (ii) the microbial activities were high during the active stage of the composting progress and evolved to stable, lower values together with a proper trend of N–NH4+ and N–NO3− at the end. Grits addition of around 6% is the optimal experimental amount to use for the composting process of the secondary sludge from the Kraft mill industry. In conclusion, treating secondary sludges and grit residues from the Kraft mill industry to produce compost is feasible and sustainable. This action reduces the environmental pollution risk (evidenced by soil pH change and possible water pollution) and improves the soil assimilation capability of inorganic micronutrients and organic compounds after application. Thus, the controlled waste reuse will pass from a negative input to the environment to a positive, sustainable solution, which can be used as a soil-nutrient improver in agriculture.

Background Urbanisation is a dominant geographical trend and an important component of global change, with unprecedented implications for socio-economic, cultural and environmental characteristics. However, green areas, including original fragments, can help to conserve native diversity, improving the functioning of these artificial systems in the long term. Urban areas can still provide habitats usable by wild birds, however the structural characteristics of the habitat formed by different types of green area differ, and therefore dissimilar bird diversities are to be expected. The object of this study was to characterise the α and β diversities of birds in different green areas and to analyse how diversity relates to ten variables that characterise the habitat. Methods We studied the green areas in the city of Temuco, southern Chile (Park, Square and Median strips of main streets), evaluating the variables: (a) surface area, (b) vegetation, (c) estimated human impact as the proportions of vegetation and bare soil by area, and the vehicle traffic. The bird assemblage structures were characterised by α (intra-environment) diversity and β diversity (between environments) and the statistical analysis identified the environmental variables related with the presence and abundance of birds. A statistical model was constructed to describe the contribution of the variables to bird diversity. Results We found significant differences between the diversity of bird species in the three types of green area. The β showed medium to high similarity between the different study units. There was a negative correlation with bare soil areas; the correlations with vehicle flow, plant structure and tree and shrub cover were not significant, meaning that these variables did not explain the variation in the richness of bird species between the green areas. However the surface area did explain this variation presenting a positive potential relation. There was also a high correlation with the origin (native) of shrub species. Conclusions The bird diversity varied significantly according to the type of urban green area. The environmental variables presenting significant correlations with bird diversity were: surface area, native species of shrub stratum, shrub cover, and bare soil area. The best multiple regression model showed that the three most important variables for bird diversity are the surface area of the green area, the cover of the shrub stratum and the presence of native shrub species.

Background The flow of goods and services occurring in catchment areas allows the production of a series of ecosystem services. These have a direct impact on the inhabitants of the territory, who in turn recognise and value ecosystems (social value) as a function of the benefits which they generate. This has a direct impact on public policies that contribute to the development of local economies. The present study therefore sought to identify and recognize the social value of the various ecosystem services provided by a mixed-use catchment area in which different productive activities are concentrated. This study examined the social value of ecosystem services and offers qualitative or quantitative, non-monetary estimates of the relative importance of different benefits for human society derived from the functioning of ecosystems (Laterra et al, Valoración de Servicios Ecosistémicos, Conceptos, herramientas y aplicaciones para el ordenamiento territorial, 2011). The methodology involved the participation of leading actors in the territory, and a panel of experts who defined criteria and weighting which were applied to a multicriteria spatial model. They assigned ordinal scale to the territory representing levels of appreciation based on the various ecosystem services in the ecological, productive, landscape and cultural dimensions. The results showed that the inhabitants of the territory recognise the ecosystem benefit of areas covered by native forest, in particular the species Nothofagus dombeyi (Mirb.) Oerst., in contrast to areas used for farm production. The functioning of the ecosystem is recognised, and particularly its contribution to regulating water flows and to water production and quality. Results The study results showed that areas covered with secondary forest of N. dombeyi provide a variety of ecosystem functions which support the creation of ecosystem services to the population, especially in riparian areas throughout the basin where they are important for water production and quality. ES ponderations for provision, regulation and cultural showed that the native forest and riparian units (HEU 1 and HEU 6) as a very important group in relation to the ES because there are recognized by the local society ( P  < 0.05). The leading actors assigned a low social value to other land-uses, like mixed use and farmland, because of the high degree of anthropisation of these ecosystems; this viewpoint has generated conflicts in the territory. Neither foresters nor farmers recognise or accept the impacts of their activities on the various ecosystem services provided by the territories where they operate, even though they are leading actors for the development of local economies. Conclusion The participation of the leading actors of a territory, represented spatially in a multicriteria analysis model, highlighted the social value of the ecosystems present in a hydrographic catchment area which supports different productive and conservation activities. The model contributed to understanding of the functional processes which generate goods and services present in the physical medium. The study used a hybrid method which included definition of homogeneous environmental units and multicriteria and multivariate statistical analysis. This allowed the information provided by the actors in the territory to be analysed with different spatial scales, levels of perception and elements of territorial planning which contribute to the generation of public policies and the sustainable management and conservation of natural ecosystems.

Fire is one of the main drivers of anthropogenic disturbances in temperate forest ecosystems worldwide, with multiple effects spread across ecological networks. Nevertheless, the biodiversity effects of fire are poorly known for species-diverse groups such as arthropods. In this research, we used a burn gradient generated two and three years after a large fire event to assess how different levels of fire severity affect arthropod diversity in the forest with the main forest forming long-living tree species Araucaria araucana, in southern Chile. The species richness and abundance of arthropods among trophic guilds was estimated annually in four fire-severity levels. We found that arthropods responded differently to fire severity levels, depending on their trophic guilds and years after fire (two and three years after fire). During the second year after fire, zoophages, phytophages, and parasitoids were more diverse in areas with high fire severity within the second year after fire, as compared to those in areas with low severity or unburned stands. In the third year after fire, a change in this trend was observed, where the abundance of all groups dropped significantly, with positive changes in the diversity in zoophages, phytophages, polyphages and saprophages, which is more noticeable in sites with high severity. These results indicate that annual variation in environmental conditions triggers bottom-up cascading effects for arthropods. Forests stands severely impacted by fires support highly fluctuating and possibly unstable arthropod assemblages. Hence, restoration efforts should be focused on recovering microhabitat conditions in these stands to allow the persistence of arthropods.

Genypterus chilensis is a marine fish of high gastronomic demand, whose capture has declined in recent years due to overfishing. In the development of the farming technology, high mortalities were obtained during egg incubation. The objective of this study is to contribute to the knowledge of fecundity and eggs viability of G. chilensis in captivity. The spawns of G. chilensis were analyzed over a period of 2 years and 3 months. The total fecundity was estimated by counting the masses and eggs produced monthly throughout the period. The results confirm that G. chilensis is a partial spawner, since a female may more than two masses of eggs per day, due to a large amount of mass spawned per season (621 average). The total production of masses of the Farming Centre during the period was 2,290; of these, only 7% (166) corresponding to 15,330,517 eggs were incubated. Because of its high fecundity, G. chilensis produces numerous masses of eggs, of which only a small percentage reaches incubation, as well as it occurs in other marine fish.