Mesoscale Meteorological Simulations of Summer Ozone Episodes in Mexicali and Monterrey, Mexico: Analysis of Model Sensitivity to Grid Resolution and Parameterization Schemes

Air quality in the Mexican cities of Monterrey, Nuevo Leon, and Mexicali, Baja California, has suffered great detriment in recent years. It is well known that meteorology is one of the main factors affecting the dynamics of pollutants in the atmosphere. Here, the Penn State/NCAR Meteorological Mesoscale Model (MM5) meteorological system was applied to identify meteorological conditions conducive to high-ozone concentrations in such regions. Two summer 2001 ozone episodes for each geographical domain were selected with the aid of a classification and regression tree analysis technique. Model response to changes in its physical parameterization, horizontal grid resolution, and data assimilation schemes were assessed. Once a suitable configuration was selected, performance statistics were computed for model validation. MM5 simulated satisfactorily the meteorology of such episodes, yielding indexes of agreement of 0.4–0.8 for wind speed and 0.67–0.95 for temperature, on average. However, MM5 tended to underestimated temperature and overestimated wind speed. Froude numbers were calculated to analyze the impact of the terrain complexity on wind circulation. It was concluded that in both cities, wind convergence zones might enhance high-ozone concentrations. These results improve our understanding of the atmospheric processes exerting effect on air pollution within these airsheds.     

Accumulation fatty acids of in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoA carboxylase,temperature, and co-immobilization with Azospirillum brasilense

The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.     

Lethal and sublethal effects of the natural and healthy spinosad-based formulation Tracer™ on tadpoles of two neotropical species

Environmental Science and Pollution Research - This paper presents the first acute toxicity data of the natural insecticide spinosad in amphibians. The sensitivity of two neotropical sympatric...     

Ecological consistency across space: a synthesis of the ecological aspects of Dromiciops gliroides in Argentina and Chile

Dromiciops gliroides is an arboreal marsupial found in the temperate forests of South America (36–43 °S). This species is the sole extant representative of the order Microbiotheria, and is a key seed disperser of many native plant species, including the keystone mistletoe Tristerix corymbosus. Here, we synthesized the current knowledge on the ecological aspects of this species, and compared the available information from Argentina and Chile. Population density (23?±?2 (mean ± SE) individual/ha) and home range (1.6?±?0.6?ha) appear to be relatively similar across a marked ecological gradient in the mainland, but lower densities (7?±?2 individual/ha) and smaller home ranges (0.26?±?0.04?ha) were detected at island sites. We detected regional variation in body condition in Chile, but there were no significant differences across a wider E-W gradient. Movement patterns fit a random walk model; such behavior might have important consequences in shaping plant’s spatial patterns. Although our data suggest that D. gliroides is more tolerant to habitat disturbance than previously thought, its incapability to disperse across non-forested areas suggests that the rapid rate of habitat loss and fragmentation that characterizes southern temperate forests likely poses a serious threat to this species. These ecological similarities are surprising given that forests studied receive dramatically different rainfall and correspond to distinct forest types. The evidence synthetized here dispels some of the myths about this species but also stresses the need for more comprehensive ecological studies across its distribution range.     

Improving Survival and Growth of Planted Austrocedrus chilensis Seedlings in Disturbed Patagonian Forests of Argentina by Managing Understory Vegetation

This study was aimed at determining, under field conditions, early interactions between planted cypress seedlings and their associated shrubs in a mesic area of Andean Patagonia and, in a nursery, the effects of increasing light availability on cypress performance when soil water was not a limiting factor. The field experiment was performed in a former cypress–coihue mixed forest (42°02′S, 71°33′W), which was replaced in the 1970s by a plantation of radiata pine. In 2005, 800 cypress seedlings were planted under maqui shrubs in a clear-cut area of the pine stand. In 2007, two treatments were set: no-competition treatment ([NCT] i.e., the surrounding aboveground biomass was removed) and competition treatment ([CT] i.e., without disturbance). The nursery experiment (42°55′S, 71°21′W) consisted of two groups: “shade” (grown under shade cloth) and “sun” (grown at full sun) cypress seedlings. After one growing season, seedling survival and stem growth (in height and diameter) were determined at both sites. Furthermore, the growth rate of leaves, stems, and roots was determined in the nursery. In the field experiment, height growth and survival in NCT were significantly greater than in CT, and a competition process occurred between cypress and surrounding shrubs. In the nursery, sun plants grew more in diameter and increased root weight more than shade plants. Results also showed that in mesic areas of Patagonia, decreasing competition and increasing light levels produced stouter seedlings better adapted to support harsh environmental conditions. Therefore, the removal of protecting shrubs could be a good management practice to improve seedling establishment.     

Policy-adaptation for a smarter and more sustainable EU electricity distribution industry: a foresight analysis

The European Union (EU) transition to a smarter and more sustainable electricity sector is driven by climate change adaptation and technological developments. For the electricity distribution industry, this has contributed to a growing need to understand how these network monopolies should adapt their role, activities, and responsibilities for a redesigned electricity market, given the growth of distributed generation, and the increased control and monitoring capabilities. Considering this, a foresight study on business model innovation, technological adaptation, and market design policy alternatives is presented. A Policy Delphi method was applied, involving two iterative survey rounds and 207 European experts, which assessed 57 policy alternatives. The results highlight adaptation challenges for implementing new technologies and business practices. Experts support innovation and transition to new roles, and innovative services, while warranting that core electricity distribution activities are secured. This shift in roles is expected to be achieved through research and development (R&D) support policies, innovation friendly regulatory frameworks, and concerted actions at the EU and Member States level. The results provide policy-adaptation guidelines for electricity distribution industry stakeholders.     

Impact assessment of climate change on farming systems in the South Mediterranean area: a Tunisian case study

Regional Environmental Change - This study considers a quantitative approach for assessing the performance of Tunisian farming systems to face climate change. It is based on the resilience concept...     

Evaluating multi-stakeholder perceptions of project impacts: a participatory value-based multi-criteria approach

This paper describes a participatory multi-stakeholder impact assessment approach based on the concept of a value tree (VT), generated using the value focused thinking method (VFT) developed by Keeney (1992 Keeney, R. 1992. Value-focused thinking, Cambridge, MA: Harvard University Press.  [Google Scholar]). This approach allows stakeholders to specify impact parameters to be evaluated, which in the context of the VT, are organized as goals, objectives and alternatives. The approach is implemented in two phases: Phase I is designed to formulate stakeholders' collective VT following VFT concepts and the cognitive mapping method, and Phase II is a participatory valuation approach based on the VT formed in Phase I. The VT and the VFT concepts are adopted as tools to capture different stakeholders' values, goals and perceptions. The resulting VT is structured as a hierarchy between goals and objectives, and a network consisting of relationships, linkages and cross-impacts of the different alternatives and objectives. The hierarchy and network structure enables stakeholders to decompose complex assessment problem into ‘smaller’ units, which makes for easier and clearer assessment context, without ignoring linkages of the units or assessment elements. The second phase allows stakeholders to express their preferences with respect to each assessment element, through a voting system that ultimately leads to measures of importance or relative weights associated with each element. A modified Analytic Hierarchy Process (called Analytic Network Process) was used to distill relative weights from the voting results. Results obtained from a case study in a Zimbabwean community forest show that the proposed approach is easy to implement and can address questions about whether a project can lead to a positive change in attitudes, and whether the changes actually lead to a propensity to adopt alternatives that the project supports (e.g. conservation-oriented alternatives).     

Neighborhood effects on seed dispersal by frugivores: testing theory with a mistletoe-marsupial system in Patagonia

The outcome of the dispersal process in zoochorous plants is largely determined by the behavior of frugivorous animals. Recent simulation studies have found that fruit removal rates and mean dispersal distances are strongly affected by fruiting plant neighborhoods. We empirically tested the effects of conspecific fruiting plant neighborhoods, crop sizes, and plant accessibility on fruit removal rates and seed dispersal distances of a mistletoe species exclusively dispersed by an arboreal marsupial in Northern Patagonia. Moreover, in this study, we overcome technical limitations in the empirical estimation of seed dispersal by using a novel 15N stable isotope enrichment technique together with Bayesian mixing models that allowed us to identify dispersed seeds from focal plants without the need of extensive genotyping. We found that, as predicted by theory, plants in denser neighborhoods had greater fruit removal and shorter mean dispersal distances than more isolated plants. Furthermore, the probability of dispersing seeds farther away decreased with neighborhood density. Larger crop sizes resulted in larger fruit removal rates and smaller probabilities of longer distance dispersal. The interplay between frugivore behavioral decisions and the spatial distribution of plants could have important consequences for plant spatial dynamics.