Environmental contaminants in four eider species from Alaska and arctic Russia

Population declines in four species of eider; common (Somateria mollissima), king (Somateria spectabilis), spectacled (Somateria fischeri) and Steller's (Polysticta stelleri), have raised concerns about exposure to contaminants. Livers and kidney tissues were collected from eiders in Alaska and Russia for organic and elemental analyses. Results showed that organochlorine and many elemental levels were below toxic thresholds; however, in many cases, cadmium, copper, lead and serenium appeared high relative to other waterfowl and may warrant concern. With the exception of lead, local anthropogenic sources for these elements are not known. Although adverse physiological responses have not been documented in eiders, these four elements cannot be ruled out as contaminants of potential concern for some eider species.     

THE EFFECTWENESS OF PRICING AS A STAND-ALONE WATER CONSERVATION PROGRAM1

ABSTRACT: Economic theory clearly indicates that the use of increasing rate structures will reduce the demand for water and produce monetary incentives for consumers to conserve. One problem with estimating the effectiveness of using rate structures as a conservation program is that they are usually accompanied by other conservation efforts. Thus, it is difficult to determine the effectiveness of any one conservation component. This paper examines the effectiveness of increasing rate structures in a situation where no other conservation program was introduced. The paper uses customer data from the Spalding County (Georgia) Water Authority where an increasing rate structure replaced a descending rate structure in January 1991. Since the imposition of the increasing rate structure, the number of customers has increased 21 percent while total water demand has gone up only 15 percent and per customer water use has declined 5 percent. The daily water use per connection has declined from 243 gallons in 1990 to 231 in 1993, and monthly use has gone from 7,381 gallons to 7,028 per connection over the same period. Statistical tests indicate that water consumption during the two periods was significantly different while weather factors were not.     

Understanding Factors That Influence Stakeholder Trust of Natural Resource Science and Institutions

Building trust between resource users and natural resource institutions is essential when creating conservation policies that rely on stakeholders to be effective. Trust can enable the public and agencies to engage in cooperative behaviors toward shared goals and address shared problems. Despite the increasing attention that trust has received recently in the environmental management literature, the influence that individual cognitive and behavioral factors may play in influencing levels of trust in resource management institutions, and their associated scientific assessments, remains unclear. This paper uses the case of fisheries management in the northeast to explore the relationships between an individual’s knowledge of the resource, perceptions of resource health, and participatory experience on levels of trust. Using survey data collected from 244 avid recreational anglers in the Northeast U.S., we test these relationships using structural equation modeling. Results indicate that participation in fisheries management is associated with increased trust across all aspects of fisheries management. In addition, higher ratings of resource health by anglers are associated with higher levels of trust of state and regional institutions, but not federal institutions or scientific methods.     

The Challenges of Incorporating Cultural Ecosystem Services into Environmental Assessment

The ecosystem services concept is used to make explicit the diverse benefits ecosystems provide to people, with the goal of improving assessment and, ultimately, decision-making. Alongside material benefits such as natural resources (e.g., clean water, timber), this concept includes—through the ‘cultural’ category of ecosystem services—diverse non-material benefits that people obtain through interactions with ecosystems (e.g., spiritual inspiration, cultural identity, recreation). Despite the longstanding focus of ecosystem services research on measurement, most cultural ecosystem services have defined measurement and inclusion alongside other more ‘material’ services. This gap in measurement of cultural ecosystem services is a product of several perceived problems, some of which are not real problems and some of which can be mitigated or even solved without undue difficulty. Because of the fractured nature of the literature, these problems continue to plague the discussion of cultural services. In this paper we discuss several such problems, which although they have been addressed singly, have not been brought together in a single discussion. There is a need for a single, accessible treatment of the importance and feasibility of integrating cultural ecosystem services alongside others.     

Linking biomarkers to reproductive success of caged fathead minnows in streams with increasing urbanization

Reproductive and oxidative stress biomarkers have been recommended as tools to assess the health of aquatic organisms. Though validated in the laboratory, there are few studies that tie a change in gene expression to adverse reproductive or population outcomes in the field. This paper looked at 17 streams with varying degrees of urbanization to assess the use of biomarkers associated with reproduction or stress in predicting reproductive success of fathead minnows. In addition, the relationship between biomarkers and water quality measures in streams with varying degrees of urbanization was examined. Liver vitellogenin mRNA was correlated with reproduction within a period of 11 d prior to sampling irrespective of habitat, but its correlation with egg output declined at 12 d and beyond indicating its usefulness as a short-term biomarker but its limits as a biomarker of total reproductive output. Stress biomarkers such as glutathione S-transferase may be better correlated with factors affecting reproduction over a longer term. There was a significant correlation between GST mRNA and a variety of anthropogenic pollutants. There was also an inverse correlation between glutathione S-transferase and the amount of the watershed designated as wetland. Egg production over the 21-d was negatively correlated with the amount of urbanization and positively correlated to wetland habitats. This study supports the development of multiple biomarkers linking oxidative stress and other non-reproductive endpoints to changes in aquatic habitats will be useful for predicting the health of fish populations and identifying the environmental factors that may need mitigation for sustainable population management.     

N-Nitroso compounds produced in deer mouse (Peromyscus maniculatus) GI tracts following hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) exposure

Given the potent carcinogenic effects of most N-nitroso compounds, the reductive transformation of the common explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to a group of N-nitroso derivatives, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in the environment have caused concerns among the general public. Questions are arising about whether the same transformations also occur in mammals, and if true, to what extent. This study investigated the N-nitroso derivatives production in the deer mouse GI tract following RDX administration. Findings verified that such transformations do occur in the mammalian GI tract at notable levels: the average MNX concentrations in deer mice stomach were 85 microg/kg and 1318 microg/kg for exposure to 10mg/kg and 100mg/kg diet, respectively. DNX in stomach were 217 microg/kg for the 10mg/kg dose group and 498 microg/kg for the 100mg/kg dose group. Changes in other toxic endpoints including body weight gain, food consumption, organ weight, and behavior were also reported.     

Morphological adaptation of a planktonic diatom to growth in Antarctic sea ice

Chaetoceros dichaeta Ehrenberg is one of the most important planktonic diatom species in the Southern Ocean, making a significant contribution to the total biomass in the region. Our observations on both field and culture material have revealed the existence of a specialized form of C. dichaeta adapted to living in sea ice. This sea ice form differs from the planktonic form by the shape and orientation of the setae and the aperture length between sibling cells. Thus, the diameter of the chain is equivalent to the apical axes of the cells and is accompanied by a two order of magnitude decrease in minimal space requirement. Here, we report for the first time on the extraordinary overwintering strategy of a planktonic diatom in sea ice facilitated by its rapid morphological adaptation to changing environmental conditions. This morphological plasticity enables it to thrive in the confined space of the sea ice brine matrix and retain its numerical dominance in recurrent growing seasons and has likely evolved to optimally exploit the dynamic ecosystem of the seasonally ice-covered seas of the Southern Ocean.     

Eradication via destratification: whole-lake mixing to selectively remove rainbow smelt, a cold-water invasive species

Invasive species can have severe effects on aquatic ecosystems. After invasions occur, eradication should be considered whenever the potential loss of ecosystem services outweighs the cost of the eradication method. Here we evaluate the possibility of destratifying Crystal Lake, Wisconsin, USA, to eradicate the invasive fish rainbow smelt (Osmerus mordax). We modeled the effects of three destratification scenarios (non-, low-, and high-mixing) using both physical and biological models. Field observations were used to calibrate the models. Water temperatures estimated from 18 unique DYRESM simulations were used in a bioenergetics model to estimate growth of five age classes of rainbow smelt under normal and destratified conditions. Our simulations indicate that destratification can eliminate optimal rainbow smelt thermal habitat resulting in mortality. Destratified lake temperatures also surpassed several physiological critical temperatures. Bioenergetics simulations predicted a weight loss of 45-55% in yearling and adult rainbow smelt. We found that destratification is potentially effective for eradicating cold-water species in temperate lakes.     

Group structure in a restricted entry system is mediated by both resident and joiner preferences

The benefits of grouping behaviour may not be equally distributed across all individuals within a group, leading to conflict over group membership among established group members, and between residents and outsiders attempting to join a group. Although the interaction between the preferences of joining individuals and existing group members may exert considerable pressure on group structure, empirical work on group living to date has focussed on free entry groups, in which all individuals are permitted entry. Using the humbug damselfish, Dascyllus aruanus, we examined a restricted entry grouping system, in which group residents control membership by aggressively rejecting potential new members. We found that the preferences shown by joining members were not always aligned with strategies that incurred the least harm from resident group members, suggesting a conflict between the preferences of residents and preferences of group joiners. Solitary fish preferred to join familiar groups and groups of size-matched residents. Residents were less aggressive towards familiar group joiners. However, resident aggression towards unfamiliar individuals depended on the size of the joining individual, the size of the resident and the composition of the group. These results demonstrate that animal group structure is mediated by both the preferences of joining individuals and the preferences of residents.