Maternal exposure to polybrominated and polychlorinated biphenyls: infant birth weight and gestational age

Understanding the influence of maternal exposures on gestational age and birth weight is essential given that pre-term and/or low birth weight infants are at risk for increased mortality and morbidity. We performed a retrospective analysis of a cohort exposed to polybrominated biphenyls (PBB) through accidental contamination of cattle feed and polychlorinated biphenyls (PCB) through residual contamination in the geographic region. Our study population consisted of 444 mothers and their 899 infants born between 1975 and 1997. Using restricted maximum likelihood estimation, no significant association was found between estimated maternal serum PBB at conception or enrollment PCB levels and gestational age or infant birth weight in unadjusted models or in models that adjusted for maternal age, smoking, parity, infant gender, and decade of birth. For enrollment maternal serum PBB, no association was observed for gestational age. However, a negative association with high levels of enrollment maternal serum PBB and birth weight was suggested. We also examined the birth weight and gestational age among offspring of women with the highest (10%) PBB or PCB exposure, and observed no significant association. Because brominated compounds are currently used in consumer products and therefore, are increasingly prevalent in the environment, additional research is needed to better understand the potential relationship between in utero exposure to brominated compounds and adverse health outcomes.     

Overview of deaths associated with natural events, United States, 1979–2004

Analysis of the National Center for Health Statistics' Compressed Mortality File showed that between 1979 and 2004, natural events caused 21,491 deaths in the United States. During this 26-year period, there were 10,827 cold-related deaths and 5,279 heat-related deaths. Extreme cold or heat accounted for 75 per cent of the total number of deaths attributed to natural events— more than all of deaths resulting from lightning, storms and foods, and earth movements, such as earthquakes and landslides. Cold-related death rates were highest in the states of Alaska, Montana, New Mexico, and South Dakota, while heat-related deaths were highest in the states of Arizona, Missouri, and Arkansas. These deaths occurred more often among the elderly and black men. Other deaths were attributed to lightning (1,906), storms and foods (2,741), and earth movements (738). Most deaths associated with natural events are preventable and society can take action to decrease the morbidity and mortality connected with them.     

Running Out of Water! Developing a Message Typology and Evaluating Message Effects on Attitude Toward Water Conservation

In three phases, this study identifies and evaluates the major messages being used in communication campaigns focused on the ongoing drought in California. A literature review in Phase 1 resulted in a typology of 12 message strategies. Following this typology, trained coders in Phase 2 evaluated water conservation messages (N?=?100) to determine whether each message utilized one or multiple strategies. The results revealed various frequencies of strategy application; and a correlational analysis rendered a pattern of strategy use in combinations. Phase 3 focused on a controlled message experiment applying the three most relevant strategies: conservation tips, loss aversion, and evidence of drought. Analysing data sampled from California residents (N?=?180), conservation messages, regardless of the strategy, led to attitude change in a negative direction. Additional analyses revealed interesting patterns of combinatorial strategy effects. The results call for a re-examination of message strategies as they may lead to several unfavourable outcomes.     

Climate change mitigation and productivity gains in livestock supply chains: insights from regional case studies

Livestock can contribute to climate change mitigation by reducing their greenhouse gas emissions and by increasing soil carbon sequestration. Packages of mitigation techniques can bring large environmental benefits as illustrated in six case studies modeled in the Global Livestock Environmental Assessment Model developed by FAO. With feasible technical interventions in livestock production systems, the mitigation potential of each of the selected species, systems and regions ranges from 14 to 41 %. While comparably high mitigation potentials were estimated for ruminant and pig production systems in Asia, Latin America and Africa, large emission reductions can also be attained in dairy systems with already high levels of productivity, in OECD countries. Mitigation interventions can lead to a concomitant reduction in emissions and increase in production, contributing to food security. This is particularly the case for improved feeding practices and better health and herd management practices. Livestock systems also have a significant potential for sequestrating carbon in pasturelands and rangelands through improved management, as illustrated in two of the six case studies in this paper.     

Major shifts in Amazon wildlife populations from recent intensification of floods and drought

In the western Amazon Basin, recent intensification of river‐level cycles has increased flooding during the wet seasons and decreased precipitation during the dry season. Greater than normal floods occurred in 2009 and in all years from 2011 to 2015 during high‐water seasons, and a drought occurred during the 2010 low‐water season. During these years, we surveyed populations of terrestrial, arboreal, and aquatic wildlife in a seasonally flooded Amazonian forest in the Loreto region of Peru (99,780 km²) to study the effects of intensification of natural climatic fluctuations on wildlife populations and in turn effects on resource use by local people. Shifts in fish and terrestrial mammal populations occurred during consecutive years of high floods and the drought of 2010. As floods intensified, terrestrial mammal populations decreased by 95%. Fish, waterfowl, and otter (Pteronura brasiliensis) abundances increased during years of intensive floods, whereas river dolphin and caiman populations had stable abundances. Arboreal species, including, macaws, game birds, primates, felids, and other arboreal mammals had stable populations and were not affected directly by high floods. The drought of 2010 had the opposite effect: fish, waterfowl, and dolphin populations decreased, and populations of terrestrial and arboreal species remained stable. Ungulates and large rodents are important sources of food and income for local people, and large declines in these animals has shifted resource use of people living in the flooded forests away from hunting to a greater reliance on fish.     

Effects of seascape connectivity on reserve performance along exposed coastlines

Seascape connectivity (landscape connectivity in the sea) can modify reserve performance in low-energy marine ecosystems (e.g., coral reefs, mangroves, and seagrass), but it is not clear whether similar spatial linkages also shape reserve effectiveness on high-energy, exposed coastlines. We used the surf zones of ocean beaches in eastern Australia as a model system to test how seascape connectivity and reserve attributes combine to shape conservation outcomes. Spatial patterns in fish assemblages were measured using baited remote underwater video stations in 12 marine reserves and 15 fished beaches across 2000 km of exposed coastline. Reserve performance was shaped by both the characteristics of reserves and the spatial properties of the coastal seascapes in which reserves were embedded. Number of fish species and abundance of harvested fishes were highest in surf-zone reserves that encompassed >1.5 km of the surf zone; were located < 100 m to rocky headlands; and included pocket beaches in a heterogeneous seascape. Conservation outcomes for exposed coastlines may, therefore, be enhanced by prioritizing sufficiently large areas of seascapes that are strongly linked to abutting complementary habitats. Our findings have broader implications for coastal conservation planning. Empirical data to describe how the ecological features of high-energy shorelines influence conservation outcomes are lacking, and we suggest that seascape connectivity may have similar ecological effects on reserve performance on both sheltered and exposed coastlines.     

Assemblage shift following population collapse of a non-indigenous bivalve in an urban lagoon

The quahog Mercenaria mercenaria has been introduced repeatedly to the Pacific coast of North America, but only one population is known to have become established. In the 1970s, the population of M. mercenaria at Colorado Lagoon, in Los Angeles County, California (33^o46′16″N, 118^o08′05″W), was estimated at more than 300,000 individuals. To determine the current status of this non-indigenous species (NIS), in 2009, we sampled 57 intertidal and 20 shallow subtidal plots, identifying and quantifying collected bivalves. No quahogs were found among the 2,490 living bivalves in our plots, though two were found intertidally outside of our plots. The M. mercenaria population has thus collapsed since 1980, but the native community has not recovered. Six of the fourteen living bivalve species we encountered were NIS; three are new records for the location, including the clam Venerupis philippinarum, which made up 87.6% of collected individuals. Though M. mercenaria is likely on its way to extinction on the US Pacific coast, the bivalve assemblage at this location remains heavily dominated by NIS.     

Marginal costs of abating greenhouse gases in the global ruminant livestock sector

Livestock [inclusive of ruminant species, namely cattle (Bos Taurus and Bos indicus), sheep (Ovis aries), goats (Capra hircus), and buffaloes (Bubalus bubalis), and non-ruminant species, namely pigs (Sus scrofa domesticus) and chickens (Gallus domesticus)] are both affected by climate change and contribute as much as 14.5 % of global anthropogenic greenhouse gas (GHG) emissions, most of which is from ruminant animals (Gerber et al. 2013). This study aims to estimate the marginal costs of reducing GHG emissions for a selection of practices in the ruminant livestock sector (inclusive of the major ruminant species—cattle, sheep, and goats) globally. It advances on previous assessments by calculating marginal costs rather than commonly reported average costs of abatement and can thus provide insights about abatement responses at different carbon prices. We selected the most promising abatement options based on their effectiveness and feasibility. Improved grazing management and legume sowing are the main practices assessed in grazing systems. The urea (CO(NH₂)₂) treatment of crop straws is the main practice applied in mixed crop–livestock systems, while the feeding of dietary lipids and nitrates are confined to more intensive production systems. These practices were estimated to reduce emissions by up to 379 metric megatons of carbon dioxide (CO₂) equivalent emissions per year (MtCO₂-eq yr^?1). Two thirds of this reduction was estimated to be possible at a carbon price of 20 US dollars per metric ton of CO₂ equivalent emissions ($20 tCO₂-eq^?1). This study also provides strategic guidance as to where abatement efforts could be most cost effectively targeted. For example, improved grazing management was particularly cost effective in Latin America and Sub-Saharan Africa, while legume sowing appeared to work best in Western Europe and Latin America.     

SOURCES OF VARIABILITY IN CONDUCTING PEBBLE COUNTS: THEIR POTENTIAL INFLUENCE ON THE RESULTS OF STREAM MONITORING PROGRAMS1

Pebble counts have been used for a variety of monitoring projects and are an important component of stream evaluation efforts throughout the United States. The utility of pebble counts as a monitoring tool is, however, based on the monitoring objectives and the assumption that data are collected with sufficient precision to meet those objectives. Depending upon the objective, sources of variability that can limit the precision of pebble count data include substrate heterogeneity at a site, differences in substrate among sample locations within a stream reach, substrate variability among streams, differences in when the substrate sample is collected, differences in how and where technicians pick up substrate particles, and how consistently technicians measure the intermediate axis of a selected particle. This study found that each of these sources of variability is of sufficient magnitude to affect results of monitoring projects. Therefore, actions such as observer training, increasing the number of pebbles measured, evaluating several riffles within a reach, evaluating permanent sites, and narrowing the time window during which pebble counts are conducted should be considered in order to minimize variability. The failure to account for sources of variability associated with pebble counts within the study design may result in failing to meet monitoring objectives.