An assessment of the impacts of timber plantations on water quality and biodiversity values of Marbellup Brook, Western Australia

Despite the fact that the establishment and maintenance of blue gum plantations can potentially result in the removal of riparian vegetation, the presence of increased levels of sediments, pesticides, and nutrients, and consequently, the loss of in-stream biodiversity, few studies exist that have looked at the impacts of timber plantations on in-stream biota. The goals of this study were thus to determine water quality, riparian condition, and in-stream biodiversity values of local streams draining blue gum plantations in the Marbellup Brook catchment in Western Australia and to compare these values with those of streams associated with other land uses. Selected water quality and habitat variables and in-stream macroinvertebrate biodiversity were measured in 2006 and 2007 at 28 sites falling into five broad categories based on the predominant land use within 200 m of each study reach. Overall, the results indicated that ??blue gum plantation?? sites often had better water quality, riparian condition, and biodiversity values than ??pasture unfenced,?? and sometimes ??pasture fenced?? sites, but water quality and biodiversity values at these sites were not as good as those associated with ??remnant?? native vegetation sites. The location of the blue gum plantation sites along the disturbance gradient investigated was attributed to both present management and past land uses in the subcatchments investigated. As this study was conducted at a time when blue gum plantations were in an on-growing phase, it was recommended that future research on the impact of blue gum plantations on waterways in southwestern Australia should include an investigation of the impacts of timber clear-cutting and extraction. Longer-term cumulative and downstream effects of blue gum plantations on local waterways also need to be investigated.     

Household disposal of pharmaceuticals: attitudes and risk perception in a UK sample

Pharmaceuticals can enter the environment through disposal in toilets, sinks and general waste. In the UK, household medicines are correctly disposed of by returning them to a pharmacy. This study examined household patterns of medicine waste, storage and disposal practices via a cross-sectional survey with 663 UK adults. Multiple regression was used to explore the contribution of key variables on self-reported medicines disposal behaviour. Analysis demonstrated that age, information, awareness, probability, attitude and intention all predicted correct disposal behaviour. Results indicate that multiple factors influence different disposal destinations uniquely. Affect and age increase disposal in sink/toilet but reduce disposal in bin. Presence of children increase bin and sink/toilet disposal but decrease pharmacy returns. Awareness and received information on correct disposal reduce bin disposal and increase pharmacy returns. The results suggest people use different mental models for each destination with disposal in sink/toilets and bins considered quicker and safer in the presence of children or for those feeling anxious. It is important to understand the capability, opportunity and motivation people have to return medicines to the pharmacy in addition to raising awareness of correct medicine disposal.

     

Bio-based films/nanopapers from lignocellulosic wastes for production of added-value micro-/nanomaterials

Environmental Science and Pollution Research - The growing demand for products with lower environmental impact and the extensive applicability of cellulose nanofibrils (CNFs) have received...     

Consumptive and nonconsumptive effects of predators on metacommunities of competing prey

Although predators affect prey both via consumption and by changing prey migration behavior, the interplay between these two effects is rarely incorporated into spatial models of predator-prey dynamics and competition among prey. We develop a model where generalist predators have consumptive effects (i.e., altering the likelihood of local prey extinction) as well as nonconsumptive effects (altering the likelihood of colonization) on spatially separated prey populations (metapopulations). We then extend this model to explore the effects of predators on competition among prey. We find that generalist predators can promote persistence of prey metapopulations by promoting prey colonization, but predators can also hasten system-wide extinction by either increasing local extinction or reducing prey migration. By altering rates of prey migration, predators in one location can exert remote control over prey dynamics in another location via predator-mediated changes in prey flux. Thus, the effect of predators may extend well beyond the proportion of patches they visit. In the context of prey metacommunities, predator-mediated shifts in prey migration and mortality can shift the competition-colonization trade-off among competing prey, leading to changes in the prey community as well as changes in the susceptibility of prey species to habitat loss. Consequently, native prey communities may be susceptible to invasion not only by exotic prey species that experience reduced amounts of mortality from resident predators, but also by exotic prey species that exhibit strong dispersal in response to generalist native predators. Ultimately, our work suggests that the consumptive and nonconsumptive effects of generalist predators may have strong, yet potentially cryptic, effects on competing prey capable of mediating coexistence, fostering invasion, and interacting with anthropogenic habitat alteration.     

Mitochondrial DNA and electronic tracking reveal population structure of Atlantic bluefin tuna (Thunnus thynnus)

Population subdivision was examined in Atlantic bluefin tuna (Thunnus thynnus) through sequencing of the control region of the mitochondrial genome. A total of 178 samples from the spawning grounds in the Gulf of Mexico, Bahamas and Mediterranean Sea were analyzed. Among the samples from these locations were 36 electronically tagged bluefin tuna that were tagged in the North Atlantic and subsequently traveled to one of these known spawning grounds during the spawning season. Bluefin tuna populations from the Gulf of Mexico and the Mediterranean Sea were found to be genetically distinct based on Φ_st, and sequence nearest neighbor analyses, showing that these two major spawning areas support independent stocks. Sequence nearest neighbor analysis indicated significant population subdivision among the Gulf of Mexico, western Mediterranean and eastern Mediterranean Sea. However, it was not possible to find significant pairwise differences between any sampling areas when using all samples. If only samples that had a high likelihood of assignment to a specific spawning site were used (young of the year, spawning adults), the differentiation increased among all sampling areas and the Western Mediterranean Sea was distinct from the Eastern Mediterranean Sea and the Gulf of Mexico. It was not possible to distinguish samples from the Bahamas from those collected at any of the other sampling sites. These data support tagging results that suggested distinctness of the Gulf of Mexico, Eastern and Western Mediterranean Sea spawning areas. This level of stock differentiation is only possible if Atlantic bluefin tuna show strong natal homing to individual spawning grounds.     

CLIMATE IMPACTS ON URBAN WATER RESOURCES IN THE SOUTHWES THE IMPORTANCE OF CONTEXT1

ABSTRACT: Stresses on water resources in the Southwest take many forms and emanate from many different sources, among which are complex institutional arrangements, significant areal and temporal climatic variability, and high urban growth rates. Further challenges to managing supply and demand in this water‐scarce region are posed by environmental, social, and legal differences within and between the individual urban areas. Analysis of the sensitivity of the urban water sector in the Southwest to climatic variability requires careful consideration of these factors. Such analysis, in turn, provides an essential foundation for effective evaluation of the region's sensitivity to longer term climate change.     

Adsorption/Desorption of Polyvinyl Alcohol on Solid Substrates and Relevant Biodegradation

The rates and extents of absorption and desorption of polyvinyl alcohol (PVA) samples on different solid substrates comprising montmorillonite, quartz sand, and farm soil, as well as humic acid mixture are reported. The uptake of PVA by the substrates was analyzed as a function of PVA hydrolysis (72–98%), molecular weight, and molecular weight distribution. Higher adsorption was detected on montmorillonite followed by farm soil, whereas the quartz sand did not display any specific adsorption affinity for the PVA. An increase in the hydrolysis degree of PVA increased the adsorption rate and extent whereas this feature was reversed by an increase in PVA molecular weight. The desorption of PVA samples from the different substrates was performed both under various pH conditions and in the presence of concentrated HF that was used to dissolve the silicon derivatives present in the substrates. Biodegradation experiments carried out in liquid cultures of PVA adsorbed on montmorillonite showed that the mineralization of the adsorbed PVA was much lower than that detected for the nonadsorbed PVA. This investigation suggests that irreversible adsorption of PVA on the clay component occurs in soil, thus substantially inhibiting PVA biodegradation.     

Histological changes in the reproductive system of male rats exposed to cigarette smoke or electronic cigarette vapor

Abstract

The use of electronic cigarettes increases as a supposedly healthier form of nicotine consumption, but safety of vaping remains uncertain. In this study, we assessed whether the use of electronic cigarettes increases the risk of infertility in male rats. Malformations of sperm morphology were more frequent in nicotine-exposed groups than in the control group. Vacuolization of seminiferous epithelium, reduction of spermatogenesis, increased apoptosis of spermatogonia and spermatocytes, and acceleration of degeneration of testes were observed. The male reproductive organs are slightly less affected by vaping than by smoking. Nevertheless, in consequence both may lead to the reduction of fertility.