Modeling effects of toxin exposure in fish on long-term population size, with an application to selenium toxicity in bluegill (Lepomis macrochirus)

A primary goal in ecotoxicology is the prediction of population-level effects of contaminant exposure based on individual-level response. Assessment of toxicity at the population level has predominately focused on the population growth rate (PGR), but the PGR may not be a relevant toxicological endpoint for populations at equilibrium. Equilibrium population size may be a more meaningful endpoint than the PGR because a population with smaller equilibrium size is more susceptible to the negative effects of environmental variability. We address the individual-to-population extrapolation problem with modeling utilizing classical mathematical theory. We developed and analyzed a general model applicable to many freshwater fish species, that includes density-dependent juvenile survival and additional juvenile mortality due to toxicity exposure, and we quantified effect on equilibrium population size as a means of assessing toxicity. Individual-level effects are typically greater than population-level effects until the individual effect is large, due to compensatory density-dependent relationships. These effects are sensitive to the recruitment potential of a population, in particular the low-density first-year survival rate S_b. Assuming high S_b could result in underestimating effects of population-level toxicity. The equilibrium size depends directly on S_b, the reproductive potential, the toxin concentration at which mean mortality is 50% (LC₅₀), and the rate at which individual mortality increases with increasing toxin concentration. More experimental data are needed to decrease the uncertainty in estimating these parameters. We then used existing data for selenium toxicity in bluegill sunfish to parameterize a simulation version of the model as an example to assess the effects of environmental stochasticity on toxicity response. Effects of environmental variability resulted in simulated extinctions at much lower toxin concentrations than predicted deterministically.     

Planning for global environmental change in Bangkok's informal settlements

Government agencies in cities across Asia recognise that municipalities must take steps to adapt to projected climate changes if people and places are to be kept above water. This paper focuses on planning for climate change in Bangkok because it ranks among the top 10 port cities vulnerable to climate change related flooding. It is also understood that the most devastating impacts of climate change will be suffered by the city's most vulnerable residents: the poor. Not only do impoverished people occupy physically vulnerable space, such as riverbanks, but they are also the least equipped to recover from the disruption of their livelihoods.

Several scholars have identified “institutional traps” that prevent the Thai government from successfully aiding poor and marginalised flood victims in the past. These include poor coordination, lack of monitoring and evaluation, rigidity, crisis management and elite capture. Lebel, Manuta, and Garden (2011, 56) Lebel, L., J.B. Manuta, and P. Garden. 2011. “Institutional Traps and Vulnerability to Changes in Climate and Flood Regimes in Thailand.” Regional Environmental Change 11 (1): 45–58.[Crossref], [Web of Science ®] , [Google Scholar] pose the crucial question: “How have individuals – from local community leaders through to national level politicians and bureaucrats – successfully influenced policy and programmes to avoid institutional traps and improve adaptive capacities to climate change?”

In this paper, we begin to address this question through examining emergent methods of “community based adaptation” and reviewing case studies of adaptation action from other vulnerable communities in the Global South. These lessons – such as overcoming institutional rigidity and avoiding elite capture – are important for Bangkok and other cities in the Global South that face many different challenges by global environmental change.     

Can home gardens scale up into movements for social change? The role of home gardens in providing food security and community change in San Jose,California

Urban policymakers and sustainable food activists have identified urban agriculture as an important strategy for confronting a host of urban problems, including food insecurity, health disparities, access to urban green space and community economic revitalisation. Much recent work on urban agriculture has examined community and school gardens, but little research has been undertaken on home gardens as a solution to urban problems. This article examines a home-gardening programme in San Jose, California, La Mesa Verde, asking whether some of the benefits found in community gardens can be found in home gardens. Specifically, we look at financial, health and community benefits, examining the potential of home gardens to become forces for broader social change. We ask whether gardens can become agents of cultural preservation, self-determination, particularly for recent immigrants who use these spaces to build identities and work towards collective action and self-determination.     

Assessing the Impacts of E. coli Laden Streambed Sediment on E. coli Loads over a Range of Flows and Sediment Characteristics

Understanding sediment Escherichia coli levels (i.e., pathogen indicators) and their contribution to the water column during resuspension is critical for predicting in‐stream E. coli levels and the potential risk to human health. The U.S. Environmental Protection Agency's current water quality testing strategies, however, rely on water borne E. coli concentrations to assess stream E. coli levels and identify impaired waters. In this work, we conducted a scenario analysis using a range of flows, sediment/water bacteria fractions, and particle sizes to which E. coli attach to assess the impact of E. coli in streambed sediments on water column E. coli levels. We used simple sediment transport theory to calculate the potential total E. coli concentrations in a stream with and without the resuspension process. Results clearly indicate that inclusion of resuspending sediment attached E. coli is necessary for watershed assessments and data on sediment attached E. coli concentrations is much needed. When neglecting the streambed sediment E. coli concentrations, the model predicted average E. coli loads of 10⁷ Colony Forming Units (CFU)/s; however, when streambed sediment E. coli concentrations were included in the model, the predictions ranged from 10¹⁰ to 10¹⁴ CFU/s. To evaluate the predictions, E. coli data in the streambed sediment and the water column were monitored in Squaw Creek, Iowa. Comparisons between measured and predicted E. coli loads yielded an R²‐value of 0.85.     

The Endorsement of the Moral Foundations in Food-Related Moral Thinking in Three European Countries

Food has become a prominent object of everyday moral discussions. This study examines how gender, political orientation, and country of origin are connected to moral foundation endorsement in food-related moral thinking. Respondents were university students (N = 371) from Finland, Denmark, and Italy who completed a word association task, in that given stimulus words were “ethical food” and “unethical food.” Results showed a presence of five moral foundations in the data, and indicated high prevalence of the Purity/Sanctity foundation in food-related moral thinking. As expected, gender differences emerged in the endorsement of the Fairness/Reciprocity and the Purity/Sanctity foundations. Also, between-country differences emerged in four of the five moral foundations, indicating that even within Europe countries may differ from each other in their endorsement of foundations. The results also verified the previously found effect of political orientation in three of the five moral foundations, although the study used a completely new and different type of method compared with previous studies. The study concludes by proposing more cross-national comparative studies where the focus is on the specific objects of moral thinking.     

A second case of intrauterine growth retardation and primary hypospadias associated with a trisomy 22 placenta but with biparental inheritance of chromosome 22 in the fetus

We report a case of severe intrauterine growth retardation (IUGR) and hypospadias in association with trisomy 22 diagnosed following chorionic villus sampling (CVS). Subsequent analysis of amniotic fluid cultures showed a normal male karyotype, 46,XY. As a previous case had been reported with similar abnormalities, in association with maternal uniparental disomy (UPD) 22, molecular studies were also performed. Microsatellite marker studies showed biparental inheritance. Follow-up studies after delivery showed a normal cell line in lymphocytes with the trisomy appearing to be confined to the placenta. The present case concurs with other earlier reports that maternal UPD for chromosome 22 has no impact on the phenotype. The features seen in the fetus are most likely the result of placental dysfunction due to trisomy, tissue-specific mosaicism and/or the effects of local growth restriction. Copyright © 2002 John Wiley & Sons, Ltd.     

Theoretical disputes over forest nitrogen fertilization

The theoretical disputes over forest nitrogen (N) fertilization constitute a difficulty for forest managers. In cases where scientists disagree it is hard for practitioners to make scientifically based decisions on what actions to take. The main objective in this study was to understand possible reasons for the scientific discussion associated with the question as to how fertilization for increased forest growth influences the forest ecosystem? Another objective was to clarify the divergent theoretical grounds within this scientific field. The study proceeded by selecting articles based on the criterion that they include field studies of fertilization for stem growth in the temperate region, and then analysing their theoretical content. Differences in theoretical grounds are among the reasons for the scientific disputes over the effects of N fertilization on forest ecosystems.     

Mitochondrial control region sequence analyses indicate dispersal from the US East Coast as the source of the invasive Indo-Pacific lionfish Pterois volitans in the Bahamas

Lionfish are popular aquarium fish from the Indo-Pacific that have invaded the western Atlantic. Two species, Pterois volitans and P. miles, were well established along the United States east coast before the first lionfish were reported from the Bahamas in 2004, where they quickly dispersed throughout the archipelago by 2007. The source of the Bahamian lionfish invasion has been in question because of the hypothesized low connectivity between Florida and Bahamas reef species as well as the temporal lag in their arrival in the Bahamas. Mitochondrial control region haplotypes (680 bp) were determined and analyzed for lionfish specimens from the Bahamas, North Carolina, and two sites within their native range (Indonesia and the Philippines). Exact tests, pairwise F _st and AMOVA analyses all showed no significant differentiation between the Bahamas and North Carolina specimens. The similarity between the Bahamas and North Carolina lionfish was also reflected in a minimum spanning network and neighbor-joining distance tree generated from the data. Sequence analyses also revealed the presence of only Pterois volitans, as no P. miles were detected in the Bahamian sample. These results indicate that the source of the Bahamian lionfish is egg and larval dispersal from the United States east coast population, and support previous models of reef fish dispersal that suggest a low level of connectivity between the Bahamas and east coast of Florida.     

Evaluating environmental education,citizen science,and stewardship through naturalist programs

Amateur naturalists have played an important role in the study and conservation of nature since the 17th century. Today, naturalist groups make important contributions to bridge the gap between conservation science and practice around the world. We examined data from 2 regional naturalist programs to understand participant motivations, barriers, and perspectives as well as the actions they take to advance science, stewardship, and community engagement. These programs provide certification‐based natural history and conservation science training for adults that is followed by volunteer service in citizen science, education, and stewardship. Studies in California and Virginia include quantitative and qualitative evaluation data collected through pre‐ and postcourse surveys, interviews, and long‐term tracking of volunteer hours. Motivations of participants focused on learning about the local environment and plants and animals, connecting with nature, becoming certified, and spending time with people who have similar interests. Over half the participants surveyed were over 50 years old, two‐thirds were women, and a majority reported household incomes of over $50,000 (60% in California, 85% in Virginia), and <20% of those surveyed in both states described themselves as nonwhite. Thus, these programs need to improve participation by a wider spectrum of the public. We interviewed younger and underrepresented adults to examine barriers to participation in citizen science. The primary barrier was lack of time due to the need to work and focus on career advancement. Survey data revealed that participants’ ecological knowledge, scientific skills, and belief in their ability to address environmental issues increased after training. Documented conservation actions taken by the participants include invasive plant management, habitat restoration, and cleanups of natural areas and streams. Long‐term data from Virginia on volunteer hours dedicated to environmental citizen science show an increase from 14% in 2007 to 32% in 2014. In general, participants in the naturalist programs we examined increased their content knowledge about ecosystems, had greater confidence in conserving them, and continued to engage as citizen scientists after completing the program.