Many techniques exist for the evaluation of nutrient pollution, but most of them require large amounts of data and are difficult to implement in countries where accurate water quality information is ...not available. New methods to manage subjectivity, inaccuracy or variability are required in such environments so that water managers can invest the scarce economic resources available to restore the most vulnerable areas. We propose a new methodology based on grey clustering which classifies monitoring sites according to their need for nitrogen pollution management when only small amounts of data are available. Grey clustering focuses on the extraction of information with small samples, allowing management decision making with limited data. We applied the entropy-weight method, based on the concept of information entropy, to determine the clustering weight of each criterion used for classification. In order to reference the pollution level to the anthropogenic pressure, we developed two grey indexes: the Grey Nitrogen Management Priority index (GNMP index) to evaluate the relative need for nitrogen pollution management based on a spatiotemporal analysis of total nitrogen concentrations, and the Grey Land Use Pollution index (GLUP index), which evaluates the anthropogenic pressures of nitrogen pollution based on land use. Both indexes were then confronted to validate the classification. We applied the developed methodology to eight estuaries of the Southern Gulf of Mexico associated to beaches, mangroves and other coastal ecosystems which may be threatened by the presence of nitrogen pollution. The application of the new method has proved to be a powerful tool for decision making when data availability and reliability are limited. This method could also be applied to assess other pollutants.
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•Grey clustering helps coastal pollution management under low data availability.•Entropy weighting identifies the main sources of water pollution from land use.•Urban development over mangroves is a relevant source of nitrogen pollution.•The limited available data in poor regions can be useful for water management.
Diverse factors may have an impact in carbon dioxide (CO2) emissions; thus, three main contributors, energy consumption, gross domestic product (GDP) and an exergy indicator are examined in this ...work. This study explores the relationship between economic growth and energy consumption by means of the hypothesis postulated for the Environmental Kuznets Curve (EKC). Panel data for ten countries, from 1971 to 2014 have been studied. Despite a wide gamma of research on the EKC, the role of an exergy variable has not been tested to find the EKC; for this reason, exergy analysis is proposed. Exergy analyses were performed to propose an exergetic indicator as a control variable and a comparative empirical study is developed to study a multivariable framework with the aim to detect correlations between them. High correlation between CO2, GDP, energy consumption, energy intensity and trade openness are observed, on the other hand not statistically significant values for trade openness and energy intensity. The results do not support the EKC hypothesis, however exergy intensity opens the door for future research once it proves to be a useful control variable. Exergy provides opportunities to analyze and implement energy and environmental policies in these countries, with the possibility to link exergy efficiencies and the use of renewables.
Globally, industry remains one of the main consumers of fossil fuels; hence, it is one of the prime sources of greenhouse gases (GHG). Exergy analysis methods can be applied to detect the processes ...inefficiencies. To enhance the interconnection of the exergy and the environment theories, renewable share and exergy efficiency are suggested, in a contribution to sustainability. Exergy analysis is proposed and lifted to study the industrial sector. Even though exergy analysis has been applied to study societies, few studies have been conducted to study emerging-market economies. In 2015, Mexico’s crude oil production was the 12th biggest worldwide, therefore fossil fuels are still the main source to produce energy for the domestic and productive sectors of the Mexican society. Consequently, a prospective study case in Mexico is suggested. The industrial sectorial exergy consumption amounts 1350 PJ in 2000, increasing to 1591 PJ in 2015. Both energy and exergy efficiencies show similar results along the 16 years, with average energy and exergy efficiencies of 78% and 23%, respectively. In comparison with results of similar studies, Mexican exergy efficiency falls within the ranges, yet below the average of 48%. Thus, poor efficiency is still occurring in the sector. Our proposal could provide significant opportunities to become a more sustainable sector, based on the exergetic renewable share and the exergy efficiency.
The progressive change in climatic conditions worldwide has increased frequency and severity of extreme hydrometeorological events (EHEs). México is an example that has been affected by the ...occurrence of EHE leading to economic, social, and environmental losses. The objective of this research was to apply a Canadian distributed hydrological model (DHM) to tropical conditions and to evaluate its capacity to simulate flows in a basin in the central Gulf of Mexico. In addition, the DHM (once calibrated and validated) was used to calculate the theoretical hydraulic power (THP) and the performance to predict streamflow before the presence of an EHE. The results of the DHM show that the goodness of fit indicators between the observed and simulated flows in the calibration process Nash-Sutcliffe efficiency (NSE) = 0.83, ratio of the root mean square error to the standard deviation of measured data (RSR) = 0.41, and percent bias (PBIAS) = −4.3) and validation (NSE = 0.775, RSR = 0.4735, and PBIAS = 2.45) are satisfactory. The DHM showed its applicability: determination of THP showed that the mean flows are in synchrony with the order of the river reaches and streamflow simulation of 13 EHEs (NSE = 0.78 ± 0.13, RSR = 0.46 ± 0.14 and PBIAS = −0.48 ± 7.5) confirmed a reliable efficiency. This work can serve as a tool for identifying vulnerabilities before floods and for the rational and sustainable management of water resources.
•Fir forest is a mono-specific forest and from late or climax successional state.•The most realistic scenarios suggest an imminent extinction of fir forests in study area.•The most important diameter ...size class that contributes to λ is >50 cm dbh followed for <10–20.•Matrices linked to climatic variation offer a useful tool to explore the growth of populations.
The demographic traits associated to climatic variations are a useful tool for the study of the dynamics of plant populations under normal conditions, as well as in different scenarios and sequences of events, such as El Niño-Southern Oscillation. Six climatic scenarios (with and without the influence of El Niño precipitation anomaly events, among others) were built and tested. The question in this study was: What is the tendency of Abies religiosa populations in relation to different climatic events? Our hypothesis is that, under a normal frequency of climatic events, the population will decrease, and that it would increase if those events accompanied by more rain were to become more frequent. Between 2012 and 2016, three reproductive cycles of Abies religiosa were registered. With these data, transition, sensibility and variation matrices were built, and population growth rates (λ) and their confidence interval estimated. Also, simulations for population dynamics under different climatic scenarios were performed. Fir forests have an inverted J shape structure, i.e., they regenerate under their own canopy. The λ of the average matrix was 0.99, with 95% variation between 0.99 and 1.053. Most likely scenarios suggest the extinction of fir forests. Abies religiosa forms mono-specific masses and represents a late or climactic successional stage. For management and conservation purposes, the most important diameter size classes are >50 cm, followed by 10–20 cm. These are the classes that contribute the most to the λ, and the ones that present greater variation. Transition matrices associated to different simulated climatic events are a useful tool to anticipate possible impacts of climatic change on forest tree population demography.
Antecedentes: Las plantaciones forestales con especies nativas de crecimiento rápido contribuyen a la captura y almacenamiento de Carbono (C). Sin embargo, se sabe poco sobre la supervivencia, el ...potencial de captura y almacenamiento de C en plantaciones con especies nativas del bosque mesófilo de montaña (BMM).Preguntas: ¿Es la supervivencia diferente entre Alnus acuminata y Trema micrantha sembrados en plantaciones?, ¿Son diferentes, la tasa anual de captura de carbono y el contenido de C total, entre ambas especies?Especies de estudio: A. acuminata y T. micrantha , de crecimiento rápido y de estados sucesionales tempranos.Sitio de estudio y fechas: Centro estado de Veracruz. 2013.Método: En plantaciones de A. acuminata y T. micrantha de tres años y medio de edad, se registró la supervivencia, el diámetro y la altura. Con estas variables se estimó el volumen, el área basal, el peso de la biomasa aérea, el contenido de C y las tasas anuales de crecimiento en altura, diámetro y contenido de carbono.Resultados: La supervivencia de A . acuminata fue mayor que T . micrantha ( P < 0.05). Las plantaciones de A . acuminata almacenaron más C (12.55 ± 0.05 Mg C ha-1) que las plantaciones de T . micrantha (11.62 ± 0.04 Mg C ha-1) ( P < 0.001). La tasa anual de captura de carbono en A . acuminata fue mayor (2.6 ± 0.0001 Mg?ha?1?año?1) que T . micrantha (2.02 ± 0.00001 Mg?ha?1?año?1).Conclusiones: Las plantaciones con especies nativas de sucesión temprana representan una estrategia viable en acciones de restauración del BMM y constituyen sumideros de carbono que pueden contribuir a la mitigación del cambio climático.
Species that coexist nowadays will not necessarily match their distributions in the future due to different climate suitability. The aim of this study was to identify potential distribution areas ...where the bark beetle Dendroctonus adjunctus and six of its host tree species overlap under different climate change scenarios. Potential distribution maps were built with species presence data using the MaxLike R library. For each projection, we used WorldClim bioclimatic variables, current and future (2050, 2070) condition climate data, two greenhouse gas concentration scenarios (RCP 4.5, RCP 8.5), and three general circulation models. The results show that the projected current potential distribution area of the bark beetle extends over 216 000 km.sup.2. This potential distribution range spans across 28 of the 32Mexican states, eight of which have not yet reported the insect's presence. Of the 72 overlapping maps that we made, the largest covers more than 118 000 km.sup.2 for Pinus duranguensis, while all future projections show a reduction in spatial coincidence. Given future climatic scenarios, D. adjunctus will probably reach higher altitudinal sites. The information contained in this study can be used to identify areas to prioritize monitoring, management, plant sanitation treatment, and reforestation strategies in Mexican pine forests.
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Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
México tiene la mayor diversidad global de especies de pinos y poco se sabe sobre la interacción Pinus-Dendroctonus. Nuestras preguntas fueron: 1) ¿Qué especies de Dendroctonus se pueden recolectar ...en trampas con atrayentes generalistas en un bosque mixto de pinos? 2) ¿Es diferente la presencia de Dendroctonus entre especies de pinos y sus clases de tamaño diamétrico? 3) ¿Cuáles son los valores de importancia ecológica relativos (VIE) de las especies de pinos? A través de un muestreo con punto cuadrante, se registraron 4 especies de pinos (Pinus montezumae, P. patula, P. pseudostrobus y P. strobus) y con el uso de trampas, 4 de Dendroctonus (D. adjunctus, D. aproximatus, D. mexicanus y D. valens). Hubo diferencias significativas en el número de Dendroctonus entre categorías diamétricas y especies de pinos. La presencia de Dendroctonus fue mayor en diámetros más grandes, con excepción de P. strobus. Pinus montezumae tuvo la mayor cantidad de individuos con presencia de Dendroctonus, pero a nivel de población, P. patula tuvo la mayor proporción de individuos con Dendroctonus (29.4%). El VIE más alto fue para P. montezumae. Sugerimos, mantener monitoreo de Dendroctonus en P. montezumae y P. patula, debido a su valor económico en la región de estudio.
Climate change together with changes in the atmosphere´s chemical composition are causing serious alterations in several ecosystems. These risks are mainly due to greenhouse gases concentrations, ...variation in rainfall periods, and the increase in the average temperature of the planet. The effects of these environmental problems have an impact on the distribution of several species. A strategy to know the affectations of these variables in the species distribution is presented in this paper. This strategy is implemented as a parallel version of a supervised classification technique called MaxLike. This parallel code runs in a Linux Centos OS based computer with 1,120 cores, 3 TB RAM. This parallel algorithm reaches a speedup of 12.56 with 16 cores configuration which improves significatively the execution time allowing a more extensive analysis of species distribution and a longer simulation over the time.
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