Shifts of the feeding niche along the size dimension of three juvenile fish species in a tidal mudflat in southeastern Brazil

The diet of three cooccurring abundant fish species (Eucinostomus argenteus, Diapterus rhombeus and Micropogonias furnieri) and its ontogenetic changes in a mudflat area of a tropical bay in southeastern Brazil were described. The working hypothesis is that these three species shift the use of the available resources throughout their growth. Early juveniles of D. rhombeus and M. furnieri fed mainly on Cyclopoida copepods, shifting to Nematoda (D. rhombeus) and errant Polychaeta (M. furnieri) as they increased in size. In contrast, the early life stages of E. argenteus fed mainly on errant Polychaeta and Calanoida copepods, with increasing niche breadth as they grew. The relative degree of individual specialisation in resource use indicated specialism for M. furnieri and E. argenteus, and generalism for D. rhombeus. The largest intraspecific overlap was found for the smallest size classes. Niche breadth increased during ontogeny, with a higher average niche breadth at lower prey length/predator length ratios. Therefore, species-specific differences in diet across the resource gradient and increased niche breadth during ontogeny characterised the shifts of resource use, and probably account for the coexistence of these species in zones of sympatry in mudflat areas of southeastern Brazil.     

Evaluation and improvement of a method for assessing HSMS from the resilience engineering perspective: A case study of an electricity distributor

This article presents an evaluation and proposals for improving a method for assessing health and safety management systems. This method takes resilience engineering (RE) as its underlying philosophy and was originally devised and tested in a case study of a manufacturing plant. Four main changes were proposed in comparison with the original version of the method: (a) a framework for assessing the use of RE principles more systematically; (b) guidelines for developing an action plan as a result of the assessment; (c) re-organization of the data collection tools in order to increase their ease of use; and (d) procedures for facilitating the assignment of scores to the items assessed. The evaluation of the method, which was not restricted to the changes described in this article, was conducted based on seven criteria for evaluating safety assessment tools. Both the evaluation and the impact of the changes are discussed based on a case study, in which the method was applied in a company that distributes electricity.     

Environmental Surveillance of SARS-CoV-2 RNA in Wastewater and Groundwater in Quintana Roo,Mexico

The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater has been reported as a result of fecal shedding of infected individuals. In this study, the occurrence of SARS-CoV-2 RNA was explored in primary-treated wastewater from two municipal wastewater treatment plants in Quintana Roo, Mexico, along with groundwater from sinkholes, a household well, and submarine groundwater discharges. Physicochemical variables were obtained in situ, and coliphage densities were determined. Three virus concentration methods based on adsorption-elution and sequential filtration were used followed by RNA isolation. Quantification of SARS-CoV-2 was done by RT-qPCR using the CDC 2020 assay, 2019-nCoV_N1 and 2019-nCoV_N2. The Pepper mild mottle virus, one of the most abundant RNA viruses in wastewater was quantified by RT-qPCR and compared to SARS-CoV-2 concentrations. The use of three combined virus concentration methods together with two qPCR assays allowed the detection of SARS-CoV-2 RNA in 58% of the wastewater samples analyzed, whereas none of the groundwater samples were positive for SARS-CoV-2 RNA. Concentrations of SARS-CoV-2 in wastewater were from 1.8 × 10³ to 7.5 × 10³ genome copies per liter (GC l⁻¹), using the N1 RT-qPCR assay, and from 2.4 × 10² to 5.9 × 10³ GC l⁻¹ using the N2 RT-qPCR assay. Based on PMMoV prevalence detected in all wastewater and groundwater samples tested, the three viral concentration methods used could be successfully applied for SARS-CoV-2 RNA detection in further studies. This study represents the first detection of SARS-CoV-2 RNA in wastewater in southeast Mexico and provides a baseline for developing a wastewater-based epidemiology approach in the area.

     

Global distribution of a key trophic guild contrasts with common latitudinal diversity patterns

Most hypotheses explaining the general gradient of higher diversity toward the equator are implicit or explicit about greater species packing in the tropics. However, global patterns of diversity within guilds, including trophic guilds (i.e., groups of organisms that use similar food resources), are poorly known. We explored global diversity patterns of a key trophic guild in stream ecosystems, the detritivore shredders. This was motivated by the fundamental ecological role of shredders as decomposers of leaf litter and by some records pointing to low shredder diversity and abundance in the tropics, which contrasts with diversity patterns of most major taxa for which broad-scale latitudinal patterns haven been examined. Given this evidence, we hypothesized that shredders are more abundant and diverse in temperate than in tropical streams, and that this pattern is related to the higher temperatures and lower availability of high-quality leaf litter in the tropics. Our comprehensive global survey (129 stream sites from 14 regions on six continents) corroborated the expected latitudinal pattern and showed that shredder distribution (abundance, diversity and assemblage composition) was explained by a combination of factors, including water temperature (some taxa were restricted to cool waters) and biogeography (some taxa were more diverse in particular biogeographic realms). In contrast to our hypothesis, shredder diversity was unrelated to leaf toughness, but it was inversely related to litter diversity. Our findings markedly contrast with global trends of diversity for most taxa, and with the general rule of higher consumer diversity at higher levels of resource diversity. Moreover, they highlight the emerging role of temperature in understanding global patterns of diversity, which is of great relevance in the face of projected global warming.     

Improving escape responses of hatchery-reared scallops <Emphasis Type="Italic">Argopecten purpuratus</Emphasis>

Hatchery rearing of the scallop Argopecten purpuratus has resulted in successive generations of scallops not exposed to predators that are less sensitive to and escape more slowly from predators than wild scallops. The present study examined whether conditioning hatchery-reared A. purpuratus to its natural predator, the sea star Meyenaster gelatinosus, improved its escape responses. Both juvenile and adult A. purpuratus from Tongoy Bay, Chile, were exposed for 7 days to different conditions: (1) continuous predator odor, (2) predator contact for 30 min three times a day, (3) a combination of the two previous conditions, and (4) no exposure to the predator (control). After conditioning, we evaluated scallop’s escape responses: reaction time, total clap number, duration of the clapping response, clapping rate, and the time scallops spent closed when exhausted. Conditioning with contact and odor plus contact (i.e., high predation risk) resulted in 25 and 50% shorter reaction times of juveniles and adults, respectively. Further, these stimuli caused juveniles to increase the number of claps and clapping rate. For adults, the time spent closed after exhaustion decreased by 50 and 63% after conditioning with contact and odor plus contact, respectively. Therefore, it is shown for the first time that exposure of scallops to increasing predator stimuli enhances escape responses, evidence of threat-sensitive predator avoidance.     

Freeze survival of the cyanobacteria Microcoleus chthonoplastes without cryoprotector

A Microcoleus chthonoplastes strain SC7B9002-1 isolated from microbial mats in tidal channels from San Carlos, Baja California Sur, Mexico was subjected to short- (15 days) and long-term (2 years) conservation assays in liquid nitrogen (-196 degrees C) using cryoprotective agents, such as 5% DMSO, 20% PVP-40, and 20% glycerol. Survival rate, chlorophyll a, protein, and nucleic acids content were observed in each case. Interesting growth and a significant increase in protein content was observed when no cryoprotectant was used during liquid nitrogen immersion. In the absence of a cryoprotectant, M. chthonoplastes lost their typical shape resembled spheroplasts, and recovery cultivation times after freezing were 5 and 25 days (short and long-term, respectively). Recovery from long-term preservation with 5% DMSO took 15 days. PVP and glycerol did not allow recovery of viable cells. The survival of M. chthonoplastes to freezing without cryoprotectant and the adaptive mechanisms that allow surviving under freezing conditions are discussed.     

Choice of threshold alters projections of species range shifts under climate change

One of the least explored sources of algorithmic uncertainty in bioclimatic envelope models (BEM) is the selection of thresholds to transform modelled probabilities of occurrence (or indices of suitability) into binary predictions of species presence and absence. We investigate the impacts of such thresholds in the specific context of climate change. BEM for European tree species were fitted combining 9 climatic models and emissions scenarios, 7 modelling techniques, and 14 threshold-setting techniques. We quantified sources of uncertainty in projections of turnover, and found that the choice of the modelling technique explained most of the variability (39%), while threshold choice explained 25% of the variability in the results, and their interaction an additional 19%. Choice of future climates explained 9% of total variability among projections. Estimated species range shifts obtained by applying different thresholds and models were grouped by IUCN-based categories of threat. Thresholds had a large impact on the inferred risks of extinction, producing 1.7- to 9.9-fold differences in the proportions of species projected to become threatened by climate change. Results demonstrate that threshold selection has large - albeit often unappreciated - consequences for estimating species range shifts under climate change.     

Parental favouritism strategies in the asynchronously hatching European Roller (<Emphasis Type="BoldItalic">Coracias garrulus</Emphasis>)

In altricial birds, resource allocation during early developmental stages is the result of an interaction between parental feeding decisions and scramble competition between nestmates. Hatching asynchrony in birds leads to a pronounced age hierarchy among their offspring. Therefore, whenever parents exert control over resource allocation parents feeding asynchronous broods should simultaneously assess individual offspring internal condition and age. In this study, we first studied whether the highly ultraviolet (UV) reflective body skin of nestlings in the asynchronous European Roller (Coracias garrulus; roller hereafter) relates to nestling quality. In a second stage, we experimentally studied parental biases in food allocation towards senior and junior sibling rollers in relation to a manipulation of UV reflectance of the skin of their offspring. Heavier roller nestlings had less brilliant and less UV saturated skins than weaker nestlings. In our experiment, we found that parents with large broods preferentially fed nestlings presenting skin coloration revealing small body size (i.e. control nestlings) over nestlings presenting skin coloration revealing large body size (i.e. UV-blocked nestlings). Within the brood, we found that parental food allocation strategy depended on nestling age: parents preferentially fed senior nestlings signalling small body size, but did not show preference between control and UV-blocked junior nestlings. These results emphasise that parent rollers use UV cues of offspring quality while balancing the age of their offspring to adjust their feeding strategies, and suggest that parents may adopt finely tuned strategies of control over resource allocation in asynchronous broods.     

Bark regeneration and tannin content in Myracrodruon urundeuva Allem?o after simulation of extractive damages��implications to management

Due to the current exploitation and consequent extinction of native medicinal plants around the world, new strategies have been proposed to address the sustainable use of this resource. Accordingly, the goal of this study is to assess the speed of bark regeneration of Myracrodruon urundeuva Allem?o and to compare the tannin content before and after tissue regeneration. Twenty individuals from an area of Caatinga in Caruaru, Pernambuco State (NE Brazil), were selected. To evaluate the speed of bark regeneration, four treatments were established, according to the area of bark removed (10 × 2, 6 × 5, 8 × 5 and 10 × 5 cm), with five replicates (five individuals of M. urundeuva Allem?o) and three treatments of tannin content (bark removed before damage, as regenerated tissue, and non-impacted bark or control). At the end of 23 months of monitoring the regeneration, we found that only seven of the 20 individuals analyzed did not fully heal. No significant correlation between the monthly percent regeneration and average monthly precipitation was found. The tannin content varied according to the quantified tissue (after damage, regenerated and control) as well as between damage classes (20 cm(2)-41.64 to 63.53 mg; 30 cm(2)-49.25 to 67.54 mg; 40 cm(2)-31.69 to 67.44 mg; 50 cm(2)-34.08 to 48.53 mg). Despite the variations found, there was no significant difference between the measurement periods (p > 0.05) or damage classes (p > 0.05). The results showed that the regeneration rate was higher in individuals belonging to the 10 × 2 and 10 × 5 cm groups and that there is no correlation between precipitation and regeneration speed. Tannin levels did not vary significantly in the tissues before damage and after regeneration.     

Lung function among residents from the largest coal region in Brazil

Environmental Science and Pollution Research - Coal mining and burning activities in coal-fired power plants are among the most polluting activities in developing countries. In Brazil, the Candiota...