Parental investment and the secondary sex ratio in northern elephant seals

Summary Data on northern elephant seals, Mirounga angustirostris, bearing on sex ratio theory were collected at Año Nuevo, California, and other Californian and Mexican Islands, during the period 1967 to 1988. The mass of males exceeded that of females by 7–8% at birth and at weaning. The sex ratio was biased to males at birth (51.2%) and was near unity at weaning (49.6% males). The sex ratio did not vary as a function of maternal age or maternal mass except in 6-year-old females, who produced significantly more males. Although sons cost more to rear in energetic terms than daughters, and mothers were more successful weaning the latter, the sex of the pup reared exerted no significant effect on the mother's reproductive performance the following year or on her subsequent survival. These data suggest that parents invest equally in sons and daughters when investment is measured in terms of future reproduction (Fisher 1930) and provide no support for the theory of adaptive shifts in sex ratio (Trivers and Willard 1973). The small sex difference in mass due to maternal effort reflects the fact that females fast during lactation and all energy transferred is from limited body stores. Because of these circumstances, selection for superior condition at the end of the period of parental investment may act more strongly on pups, who have the opportunity to steal milk, than on their mothers.     

Evaluation of a gradient sampling design for environmental impact assessment

Before-After Control Impact (BACI) sampling designsare commonly used in environmental impact assessmentand are considered the most effective for detectingchanges due to anthropogenic disturbances. Thesedesigns handle local spatial variability throughrandomized placement of samples into a treatmentstratum and a control stratum. When a contaminantdisperses with distance from a point source it issuggested that a gradient design will be moresensitive to change than randomized placement ofsamples. This requires allocating samples according todistance, rather than by random placement withinrandomly placed blocks. In this paper gradient versusrandom sampling designs were compared using data froman oil field in the North Sea. The gradient samplingdesign was more powerful than a randomized CI sampling design.     

Using Social Network Analysis to examine the role that institutional integration plays in community-based adaptive capacity to climate change in Caribbean small island communities

Remote island communities in the Caribbean are known to be disproportionately vulnerable to the impacts of climate change. As a result, there is a need to better understand the factors that contribute to increasing local-scale adaptive capacity through large-scale adaptation projects. While it has been argued that strong institutional networks are highly influential in a community’s ability to leverage funds and to implement tailored adaptation projects, limited empirical research has been undertaken. Social Network Analysis was used to retrospectively evaluate the importance of institutional integration for enhancing adaptive capacity in the small island community of Paget Farm in St. Vincent and the Grenadines. Paget Farm successfully adapted to a lack of fresh water through the implementation of a funded solar-powered desalination plant – and as a result the community represents an ideal case study for analysis. Results reveal that while the level of vertical integration varied throughout the temporal phases of the adaptation project, horizontal integration was consistently low. These findings suggest that high integration between institutions may not be required during all project phases in order to ensure success and that more consistent rather than high levels of integration between sectors may be more meaningful for enhancing adaptive capacity.     

Use of Probabilistic Methods to Understand the Conservatism in California’s Approach to Assessing Health Risks Posed by Air Contaminants

Many state and federal agencies have prepared risk assessment guidelines, which describe methods for quantifying health risks associated with exposure to vapors and particulates emitted from point and area sources (e.g., California Air Pollution Control Officers Association [CAPCOA] under the Air Toxics “Hot Spots” Act [Assembly Bill 2588] and the U.S. Environmental Protection Agency [EPA] under the Clean Air Act). In general, these guidelines recommend or require the use of upper bound “point” estimates for numerous exposure parameters. This methodology yields a single risk estimate, which is intended not to underestimate the true risk and may significantly overstate it. This paper describes a risk assessment of a facility’s airborne emissions using a probabilistic approach, which presents a range and distribution of risk estimates rather than a single point estimate. The health risks to residents living near a food processing facility, as estimated using techniques recommended by California AB2588, are compared to the results of a probabilistic analysis. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were identified as the emitted chemicals of concern. The point estimate method recommended by CAPCOA resulted in estimates that were greater than the 99.99th percentile risk predicted by the probabilistic analysis. As shown in other assessments of persistent airborne chemicals, secondary or indirect exposure pathways (i.e., ingestion of beef, ingestion of cow’s milk, and ingestion of mother’s milk) rather than inhalation, were the greatest contributors to risk. In this analysis, the probability distributions for the cancer potency factor and ingestion of cow’s milk had the largest impact on the results of the 33 exposure factors considered.     

The relationship between environmental activism,pro-environmental behaviour and social identity

Research on environmental activism remains poorly integrated and ill-defined and to date, there has been little examination of the relationship of environmental activism, pro-environmental behaviour and social identity. 131 students from an Australian University (M = 25.04 years old, SD = 8.17) voluntarily participated by returning an anonymous questionnaire containing an environmental activism scale, a pro-environmental behaviour scale and a social identity scale. The results revealed that while there was a significant relationship between social identity and environmental behaviour, only the citizenship component of environmental behaviour significantly predicted environmental activism. In other words, the relationship between social identity and environmental activism was indirect. This research presents the opportunity for further exploration of these relationships and to further investigate their relationship to inter-group processes.     

Social participation and climate change

Social participation has been broadly analysed by comparing case studies of different types of socio-economic developments in Brazil and the United Kingdom (UK). A key objective has been to consider how effective social participation has been in incorporating society’s points of view in the decision making process. In most cases, it would appear that very little can be done by stakeholders to change big decisions on development policies that support public and private development because in reality social participation often only provides an opportunity for discussion and agreement on specific issues regarding how development will be undertaken and how stakeholders will be affected. Although Brazil and the United Kingdom have socio-economic and cultural differences, it is necessary to emphasize that education, self-organization and knowledge of civil rights are crucial for an effective social participation process. As climate change is an important topic for present and future generations and that some of the development activities analysed in this study will emit greenhouse gases, this study also attempts to investigate if climate change mitigation strategies have been integrated into the social participation process. Investigation shows that there is little evidence that climate change mitigation actions involving stakeholders have been integrated into development strategies or have been part of social participation schemes in the case studies analysed. Having said that, the study also describes positive examples of climate change mitigation actions in different parts of the world that involve local people in ‘carbon-neutral’ or ‘social-carbon’ projects and proposes the creation of a carbon-neutral committee that would be responsible for coordinating climate change mitigation measures within development proposals such as the ones analysed in this study.     

Occurrence of polycyclic musks in wastewater and receiving water bodies and fate during wastewater treatment

The occurrence of cashmerane (DPMI), celestolide, phantolide, traesolide (ATII), galaxolide (HHCB) and tonalide (AHTN) in sewage and surface waters and their fate during wastewater treatment and anaerobic sludge digestion is investigated. AHTN and HHCB are the most important representatives and influent concentrations of 0.41-1.8 and 0.9-13 μg L⁻¹ are observed. DPMI is detected in influent and effluent samples but in notably lower concentrations than AHTN and HHCB. Major sources of polycyclic musks are households, whereas industrial emitters seem to be of minor importance. This conclusion is supported by the analysis of selected industrial wastewaters (metal, textile and paper industry). Specific emissions of 0.36 ± 0.19 and 1.6 ± 1.0 mg cap⁻¹ d⁻¹ for AHTN and HHCB are calculated. Overall removal efficiencies between approx 50% and more than 95% are observed during biological wastewater treatment and removal with the excess sludge is the major removal pathway. Log K_D values of 3.73-4.3 for AHTN, 3.87-4.34 for HHCB and 2.42-3.22 for DPMI are observed in secondary sludge. During sludge digestion no or only slight removal occurred. Mean polycyclic musk concentrations in digested sludge amounted to 1.9 ± 0.9 (AHTN), 14.2 ± 5.8 (HHCB), 0.8 ± 0.4 (ATII) and 0.2 ± 0.09 (DPMI) mg kg⁻¹ dry matter. In the receiving water systems a comparable distribution as during wastewater treatment is observed. AHTN, HHCB and DPMI are detected in surface waters (ND (not detected) - < 0.04, ND - 0.32 and ND - 0.02 μg L⁻¹) as well as AHTN and HHCB in sediments (ND - 20, ND - 120 μg kg⁻¹). For HHCB an apparent K_OC value of 4.1-4.4 is calculated for sediments. Major source for polycyclic musks in surface waters are discharges from wastewater treatment plants. For HHCB and DPMI 100% of the load observed in the sampled surface waters derive from discharges of treated wastewater.     

Risk assessments for forest trees: the performance of the ozone flux versus the AOT concepts

Published ozone exposure-response relationships from experimental studies with young trees performed at different sites across Europe were re-analysed in order to test the performance of ozone exposure indices based on AOTX (Accumulated exposure Over a Threshold of X nmol mol(-1)) and AF(st)Y (Accumulated Stomatal Flux above a threshold of Y nmol m(-2) s(-1)). AF(st)1.6 was superior, as compared to AOT40, for explaining biomass reductions, when ozone sensitive species with differing leaf morphology were included in the analysis, while this was not the case for less sensitive species. A re-analysis of data with young black cherry trees, subject to different irrigation regimes, indicated that leaf visible injuries were more strongly related to the estimated stomatal ozone uptake, as compared to the ozone concentration in the air. Experimental data with different clones of silver birch indicated that leaf thickness was also an important factor influencing the development of ozone induced leaf visible injury.     

Shoot growth of mature Fagus sylvatica and Picea abies in relation to ozone

Epidemiological analysis of sequential growth data may be a tool in assessing ozone sensitivity of mature trees. Annual shoot growth of mature Fagus sylvatica in 83 Swiss permanent forest observation plots and of Picea abies in 61 plots was evaluated for 11 and 8 consecutive years, respectively, using branches harvested every 4 years. The data were assessed as annual deviation from average growth and related to fructification, ozone, meteorological parameters, and modelled soil water content using a mixed linear model. In beech, a significant association between ozone and shoot growth was observed which corresponded to a 7.4% growth reduction between 0 and 10 ppm h AOT40 (accumulated ozone over threshold 40). This is in the same order of magnitude as the response observed in experiments with seedlings. No interaction was found between ozone and drought parameters. In Norway spruce, shoot growth was neither associated with ozone nor with drought.