Behavior of fenhexamid in soil and water

A study was conducted to investigate fenhexamid (FEX) behavior in soil and in water. FEX proved to be rather stable at acid pH but showed slight degradation at neutral and alkaline pH. After 101 days of FEX spiking of a soil sample, 94% at pH 4, 12% at pH 7 and 23% at pH 9 of the active ingredient was still present. In natural water the rate of FEX disappearance appeared to be slow which may be due to abiotic rather than biotic processes. The soil degradation tests showed low persistence of the active ingredient if a good microflora activity is guaranteed (DT(50) about 1 day). Moreover, in absence of microorganisms, FEX proved to be stable. Humidities of 25 and 50% of Water Holding Capacity (WHC) influenced in equal measure the rate of degradation. From the same soil, a bacterium was isolated and identified as Bacillus megaterium, which was able to metabolize FEX with the hydroxylation of the cyclohexane ring. Moreover, FEX showed an elevated affinity for humic acid (73%), smectite (31%), and ferrihydrite(20%) and low affinity for vermiculite (11%) and kaolinite (7%).     

Veterinary drugs in groundwater in a dairy region of central Argentina and risk assessment for human health

Veterinary drugs used in dairy production are potential contaminants of surface or groundwater sources, being able to affect human and environmental health. It is known that chronic exposure to antibiotics in low concentrations present in water can generate microbial resistance. This study aimed to evaluate the presence of veterinary drugs in 53 groundwater samples used for animal and human consumption, collected in dairy milking parlors, in an important milk-producing area of central Argentina, and to assess the risk to human health when they are used as drinking water. In 75% of the total samples analyzed, at least one veterinary drug was detected. The most frequently found drugs in water samples were the antibiotics tetracycline in 58.5% and oxytetracycline in 56.6%, and an anti-inflammatory, flunixin in 39.6%. In the water samples, the tetracycline and oxytetracycline concentrations were between 0.1 and 5.3 μg/L and flunixin concentrations were between 0.01 and 2.1 μg/L. The frequency of appearance and the concentration levels of the substances found in the water samples were evaluated according to the productivity, size, and production system (confined or pasture) of the dairy farms. Higher concentrations and proportions of water samples containing antibiotics were observed when the number of animals per dairy farm was >182 and when the productivity was high (>25 liters per animal per day). In the case of flunixin, the percentage of detection was similar in all evaluated categories. The risk assessment for children and adults, considering the intake of drinking water containing residues of these drugs, did not indicate a significant health risk. It would be advisable to evaluate other sources of drinking water, both surface and underground, in other regions of the country, to provide data to assess the impact of these substances and the other contaminants on environmental and human health.     

Associations of Forest Cover,Fragment Area,and Connectivity with Neotropical Understory Bird Species Richness and Abundance

Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800‐ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species‐richness estimates were significantly higher (F= 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30–50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30–50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30–50%). Highly sensitive species were 3‐4 times more common above the 30–50% threshold than below it; however, our results do not support a unique fragmentation threshold. Asociaciones de la Cobertura Forestal, Superficie del Fragmento y Conectividad con la Riqueza y Abundancia de Aves Neotropicales de Sotobosque     

Interactive effects of male and female age on extra-pair paternity in a socially monogamous seabird

Females sometimes obtain older sires for their offspring through extra-pair interactions, but how female age influences paternity is largely unexplored and interactive effects across the age span of both sexes have not been analyzed. To test whether female choice of sire age varies with female age in the blue-footed booby (Sula nebouxii), we examined associations between ages of both partners and the probability of extra-pair paternity (EPP) in 350 broods of parents up to 22 years old in a single breeding season. Extra-pair paternity enables a female to select an alternative sire for her offspring and could function to avoid or achieve particular combinations of parental ages. A male age?×?female age interaction revealed that in young females (≤4 years), EPP decreased with increasing age of the social partner, whereas in old females (≥8 years), it increased. Moreover, sires of extra-pair (EP) chicks of young females paired to young males were on average 6.33 years older than the females’ social partners. Since female boobies control copulatory access, this pattern could imply that young females choose old sires for their proven genetic quality and that old females avoid very old males because matings with them may risk infertility or genetic defects in offspring. Taking female age into account and observing across the whole age span may be necessary for understanding female age-based mate choice.     

From science to policy—a geostatistical approach to identifying potential areas for cetacean conservation: a case study of bottlenose dolphins in the Pelagos sanctuary (Mediterranean Sea)

Cetaceans are top-level predators that serve as sentinels of the health and status of lower trophic levels in the marine ecosystem. For this reason they attract significant attention in marine conservation planning and often have been used to promote designation of reserve areas in many countries (e.g., Ligurian Sea, Moray Firth, Hawaiian Islands, The Gully, Wadden Sea, Banks Peninsula, and Golfo San José). Many policies are designed to protect cetaceans. For example, the Habitat Directive requires member states to select, designate, and protect sites that support certain natural habitats or species, such as the bottlenose dolphin, as Special Areas of Conservation (SACs) that aim to create a network of protected areas across the European Union known as Natura 2000. The boundaries of protected areas for cetacean species must be defined for management purposes. In recent years, many techniques have been developed to define the distribution of cetaceans in relation to habitat preferences. Although these models can provide an understanding of the ecological processes that determine species distribution, their application requires prior knowledge of the variables that should be included in the model, the interactions among these variables, and their effects on species distribution. Thus, the lack of available data in understudied areas precludes the application of these types of models. As an alternative, we describe a geostatistical approach to identifying areas that potentially should be designated as marine protected areas for cetaceans. We illustrate the application of the kriging algorithm to the bottlenose dolphin population that resides in the northwestern Mediterranean Sea. The data derived from a 7-year survey were used. The encounter rate is the only variable required for this method, making it very easy to apply. The resulting georeferenced and high resolution map includes areas most visited by bottlenose dolphins, which are called core areas. Core areas are helpful for establishing the boundaries of marine reserves for the protection of the species. The approach described herein is accurate, precise, unbiased, replicable to all highly mobile species and easy to understand by both researchers and policy makers.     

Physical and biological controls of algal blooms in the Río de la Plata

Coupled three-dimensional hydrodynamic and ecological numerical simulations were used to investigate the role of transport, stagnation zones and dispersion on inter-annual blooms of the diatom Aulacoseira sp. in the vicinity of the drinking water intakes of the Buenos Aires city (Argentina) in the upper Río de la Plata. Three different summer events were analyzed. First, a mild biomass bloom year (2006–2007), second, a high biomass bloom year (2007–2008) and third, a “normal” no bloom year (2009–2010). Simulated water height, water temperature, suspended solids and chlorophyll \(a\) concentrations patterns compared well with field data. Results revealed that the advection of phytoplankton cells via inflows to the Río de la Plata triggered Aulacoseira sp. blooms in the domain. In addition, excessive growth observed near the drinking water intakes, along the Argentinean margin, were associated with long retention times (stagnant region) and weak horizontal dispersion. Increased concentrations of suspended solids in the water column, in response to re-suspension events, did not prevent the blooms, however, were found to also play a key role in controlling the rate of phytoplankton growth. Finally, a non-dimensional parameter, R, that considers phytoplankton patch size, e-folding growth and dispersion time scales is shown to determine the potential bloom occurrences, as well as bloom intensity; R values higher than 5.7 suggest intense phytoplankton growth. For the mild biomass bloom year, \(R = 7.5\) , for the high biomass bloom year, \(R = 11\) and for the “normal” no bloom year \(R= 0.4\) .     

Analysis of welding fumes: A short note on the comparison between two sampling techniques

It is well established that welding fumes contain toxic substances, and that its composition is dependent on multiple factors, such as nature of the welding process and chemical compositions of the welding consumables and base materials. In order to prevent accidents and, thus to contribute to the safety of protection of welders, the establishment of a database on welding fume components is considered as essential. This has led to the development and upgradation of sampling techniques of welding fumes. Up to now, few standard techniques exist in this area. This study describes the results of the analysis of welding fumes, in terms of heavy metals, for a set of welding electrodes commonly used in carbon steel manufacture. Sampling was done by two different techniques: using the one currently known as “fume box” and common techniques in workplace atmospheres.     

Endocrine disruptors in the Leça River and nearby Porto Coast (NW Portugal): presence of estrogenic compounds and hypoxic conditions

The Leça River and two beaches close to the north and south margins of the estuary, nowadays an important seaport harbor, show signs of contamination. However, the chemical nature of that contamination is uncertain. Therefore, this study checked for the presence of 11 endocrine disrupting compounds (EDCs) of animal (17β-estradiol and estrone), pharmaceutical (17α-ethynylestradiol), and industrial (alkylphenols, alkylphenol ethoxylates, and bisphenol A) origins in water samples collected from six points at the river gradient and at two sites in the coastline (Atlantic Ocean). Along with the EDCs, evaluated by gas chromatography – mass spectroscopy (GC-MS) during spring, summer, and autumn, physico-chemical parameters were also assessed and particular attention was given to dissolved oxygen (DO) levels. Data showed the presence of high amounts of estrogens (up to 10?ng?L^?1 for estrone) and industrial compounds (up to 2?µg?L^?1 for the nonylphenol ethoxylates) at both river and seacoast. Along with this, clear signs of hypoxia were found in the river (DO??1 at several sampling sites). Taking into account these issues, it was concluded that there are local conditions for the occurrence of endocrine disruption in aquatic animals.     

Functional traits and the growth-mortality trade-off in tropical trees

A trade-off between growth and mortality rates characterizes tree species in closed canopy forests. This trade-off is maintained by inherent differences among species and spatial variation in light availability caused by canopy-opening disturbances. We evaluated conditions under which the trade-off is expressed and relationships with four key functional traits for 103 tree species from Barro Colorado Island, Panama. The trade-off is strongest for saplings for growth rates of the fastest growing individuals and mortality rates of the slowest growing individuals (r2 = 0.69), intermediate for saplings for average growth rates and overall mortality rates (r2 = 0.46), and much weaker for large trees (r2 < or = 0.10). This parallels likely levels of spatial variation in light availability, which is greatest for fast- vs. slow-growing saplings and least for large trees with foliage in the forest canopy. Inherent attributes of species contributing to the trade-off include abilities to disperse, acquire resources, grow rapidly, and tolerate shade and other stresses. There is growing interest in the possibility that functional traits might provide insight into such ecological differences and a growing consensus that seed mass (SM), leaf mass per area (LMA), wood density (WD), and maximum height (H(max)) are key traits among forest trees. Seed mass, LMA, WD, and H(max) are predicted to be small for light-demanding species with rapid growth and mortality and large for shade-tolerant species with slow growth and mortality. Six of these trait-demographic rate predictions were realized for saplings; however, with the exception of WD, the relationships were weak (r2 < 0.1 for three and r2 < 0.2 for five of the six remaining relationships). The four traits together explained 43-44% of interspecific variation in species positions on the growth-mortality trade-off; however, WD alone accounted for > 80% of the explained variation and, after WD was included, LMA and H(max) made insignificant contributions. Virtually the full range of values of SM, LMA, and H(max) occurred at all positions on the growth-mortality trade-off. Although WD provides a promising start, a successful trait-based ecology of tropical forest trees will require consideration of additional traits.     

Combined effect of fire and water scarcity on vegetation patterns in arid lands

In many arid zones around the word, the vegetation spontaneously forms regular patterns to optimize the use of the scarce water resources. The patterns act as early warning signal that fragile ecosystems may suddenly undergo irreversible shifts, thus, interpreting the structural shape of vegetation patterns is crucial to deciphering the ecosystem history and its expected further development. The sudden and irreversible shift of delicate ecosystems as a consequence of minor variation of the climatic forcing has been studied extensively in the past. The attitude of the ecosystem to recover after a catastrophic event, such as fire, did not receive as much attention so far. Here we modelled fire, as a sudden shift of the ecosystem state variables and functionality and evaluated post-fire scenarios under the hypothesis that two major feedbacks shaped the vegetation patterns: a positive feedback between preferential infiltration and plant growth, and a second feedback between infiltration and vegetation burning. A simple model solving a set of partial differential equations for soil moisture, plant biomass, surface water and dead biomass balance predicted significantly diverse post-fire vegetation patterns depending on the fire severity and on the degree of soil water repellency induced by the vegetation burning.