The response of the woodpigeon (Columba palumbus) to relaxation of intraspecific competition: A hybrid modelling approach

The recent rapid growth of the woodpigeon population in the British Isles is a cause for concern for environmental managers. It is unclear what has driven their increase in abundance. Using a mathematical model, we explored two possible mechanisms, reduced intraspecific competition for food and increased reproductive success. We developed an age-structured hybrid model consisting of a system of ordinary differential equations that describes density-dependent mortality and a discrete component, which represents the birth-pulse. We investigated equilibrium population dynamics using our model. The two hypotheses predict contrasting population age profiles at equilibrium. We adapted the model to examine the impacts of control measures. We showed that an annual shooting season that follows the period of density-dependent mortality is the most effective control strategy because it simultaneously removes adult and juvenile woodpigeons. The model is a first step towards understanding the processes that influence the dynamics of woodpigeon populations.     

Restoration of a Canadian Prairie Wetland with Agricultural and Municipal Wastewater

3 /day (800,000 US gallons) of municipal wastewater and beef processing wastewater. A large nongovernmental organization hastened restoration with a development process that outlined restoration goals and management objectives to satisfy a dual mandate of wastewater treatment and wildlife habitat creation. In 1995, after five years of wastewater additions, the basins had been refilled and the surrounding uplands had been acquired and restored. The Frank Lake Conservation Area currently provides high-quality habitat for a variety of wildlife in a region where many of the native plants and animals species have been lost due to habitat loss and fragmentation. The success of upland and water management strategies is reflected in the increase of target species' abundance and richness: 50 shorebird species, 44 waterfowl species, 15 raptor species, and 28 other new bird species have returned to the marsh since restoration. As well, significant N and P reduction occurs as waters flow through the first basin of the marsh. The management strategies of this project that satisfied a dual mandate serve as a model to guide managers of other large-scale wetland restoration projects.     

Legislating child restraint usage -Its effect on self-reported child restraint use rates in a central city

Objective

To assess the effect of the newly enacted child passenger safety law, Wisconsin Act 106, on self-report of proper restraint usage of children in Milwaukee's central city population.

Method

A prospective, non-randomized study design was used. The settings used were (a) a pediatric urban health center, and (b) two Women, Infants and Children offices in Milwaukee, Wisconsin. Participants included 11,566 surveys collected over 18 months that spanned the pre-legislation and post-legislation time periods from February 2006 through August 2008.

Results

The study set out to assess appropriate child passenger restraint. The results showed that the changes in adjusted proper restraint usage rates for infants between the pre-law, grace period, and post-fine periods were 94%, 94%, and 94% respectively. For children 1-3 years old, the adjusted proper usage rates were 65%, 63%, and 59%, respectively. And for children 4-7 years old, the rates were 43%, 44% and 42%, respectively. There was a significant increase in premature booster seat use in children who should have been restrained in a rear- or forward-facing car seat (10% pre-law, 12% grace period, 20% post-fine; p < 0.0005). There was no statistically significant change over time in unrestrained children (2.1%, 1.7%, 1.7%, p = 0.7, respectively).

Conclusions

The passage of a strengthened child passenger safety law with fines did not significantly improve appropriate restraint use for 0-7 year olds, and appropriate use in 1-7 year olds remained suboptimal with a majority of urban children inappropriately restrained. Although the number of unrestrained children decreased, we identified an unintended consequence of the legislation - a significant increase in the rate of premature belt-positioning booster seat use among poor, urban children.

Impact on Industry

The design of child restraint systems maximizes protection of the child. Increasing reports of misuse is a call to those who manufacture these child passenger restraints to improve advertising and marketing to the correct age group, ease of installation, and mechanisms to prevent incorrect safety strap and harness placement. To ensure accurate and consistent use on every trip, car seat manufacturers must ensure that best practice recommendations for use as well as age, weight, and height be clearly specified on each child restraint. The authors support the United States Department of Transportation's new consumer program that will assist caregivers in identifying the child seat that will fit in their vehicle. In addition, due to the increase in premature graduation of children into belt-positioning booster seats noted as a result of legislation, promoting and marketing booster seat use for children less than 40 pounds should not be accepted. Child passenger safety technicians must continue to promote best practice recommendations for child passenger restraint use and encourage other community leaders to do the same.     

Nitrogen and phosphorus attenuation within the stream network of a coastal, agricultural watershed

Streams alter the concentration of nutrients they transport and thereby influence nutrient loading to estuaries downstream; however, the relationship between in-stream uptake, discharge variability, and subsequent nutrient export is poorly understood. In this study, in-stream N and P uptake were examined in the stream network draining a row-crop agricultural operation in coastal North Carolina. The effect of in-stream nutrient uptake on estuarine loading was examined using continuous measurements of watershed nutrient export. From August to December 2003, 52 and 83% of the NH4+ and PO4(3-) loads were exported during storms while concurrent storm flow volume was 34% of the total. Whole-ecosystem mass transfer velocities (Vf) of NH4+ and PO4(3-), measured using short-term additions of inorganic nutrients, ranged from 0.1 to 25 mm min(-1). Using a mass balance approach, this in-stream uptake was found to attenuate 65 to 98% of the NH4+ flux and 78 to 98% of the PO4(3-) flux in small, first-order drainage ditches. For the larger channel downstream, an empirical model based on Vf and discharge was developed to estimate the percentage of the nutrient load retained in-stream. The model predicted that all of the upstream NH4+ and PO4(3-) load was retained during base flow, while 65 and 37% of the NH4+ and PO4(3-) load was retained during storms. Remineralization from the streambed (vs. terrestrial sources) was the apparent source of NH4+ and PO4(3-) to the estuary during base flow. In-stream uptake reduced the dissolved inorganic N to dissolved inorganic P ratio of water exported to the N-limited estuary, thus limiting the potential for estuarine phytoplankton growth.     

Empowered to lead: the role of psychological empowerment in leadership

This study examines the relationship between psychological empowerment and leadership. Empowered supervisors are hypothesized to be innovative, upward influencing, and inspirational and less focused on monitoring to maintain the status quo. Tested on a sample of mid‐level supervisors from a Fortune 500 organization, the hypotheses were largely supported. Supervisors who reported higher levels of empowerment were seen by their subordinates as more innovative, upward influencing, and inspirational. No relationship was found between supervisory empowerment and monitoring behaviours. Implications for theory and practice are discussed, and future research directions are suggested. Copyright © 1999 John Wiley & Sons, Ltd.     

Development of a spatial web tool to identify hotspots of environmental burdens in Wallonia (Belgium)

Environmental Science and Pollution Research - In response to the Walloon Environment and Health Program, the Scientific Institute of Public Services (ISSeP) developed an integrated approach of...     

How Technology Features Influence Public Response to New Agrifood Technologies

New agrifood technologies are often difficult to grasp for the public, which may lead to resistance or even rejection. Insight into which technology features determine public acceptability of the technology could offer guidelines for responsible technology development. This paper systematically assesses the relative importance of specific technology features for consumer response in the agrifood domain in two consecutive studies. Prominent technology features were selected from expert judgment and literature. The effects of these features on consumer evaluation were tested in a consumer study (n = 745). Fictitious technologies were used to avoid any uncontrollable contextual influences that existing new technologies may evoke. Results show that technologies that were seen as more natural and newer were perceived less risky, more beneficial, and were evaluated more positively. Technologies applied to food were judged to be more beneficial, but also more risky than those applied to non-food. Technologies used in the production process were perceived to be less risky and evaluated more positively than those used in the product. Technologies owned by the market leader were perceived to be more beneficial, and evaluated more positively than those that were freely available. In a next study (n = 440), effects of the technology features on consumer response were tested for existing new agrifood technologies. This study replicated the results for perceived naturalness, perceived newness, and place in the production process where the technology is applied. However, in contrast to the first study, we did not find an effect of application area (food versus non-food) and technology ownership.     

The fate and transport of arsenic species in the aquatic ecosystem: a case study on Bestari Jaya,Peninsular Malaysia

The field of arsenic pollution research has grown rapidly in recent years. Arsenic constitutes a broad range of elements from the Earth’s crust and is released into the environment from both anthropogenic and natural sources due to its relative mobility under different redox conditions. The toxicity of arsenic is described in its inorganic form, as inorganic arsenic compounds can leach into different environments. Sampling was carried out in the Bestari Jaya catchment while using a land use map to locate the site, and experiments were conducted via sequential extraction and inductively coupled plasma optical emission spectroscopy to quantify proportions of arsenic in the sediment samples. The results show that metals in sediments of nonresidual fractions, which are more likely to be likely released into aquatic environments, are more plentiful than the residual sediment fractions. These findings support the mobility of heavy metals and especially arsenic through sediment layers, which can facilitate remediation in environments heavily polluted with heavy metals.