Water Table Regime Regulates Litter Decomposition in Restiad Peatlands,New Zealand

A 5-year litterbag study examined decomposition rates at four sites representing restiad peatland succession in Waikato, New Zealand. Early successional sites were dominated by Baumea rubiginosa, or Leptospermum scoparium, mid-successional by Empodisma robustum, and late successional by Sporadanthus ferrugineus. Leaf/culm materials from these species were placed on the surface, and roots of Empodisma and Sporadanthus buried at depths of 5, 25, and 55 cm to test the influence of succession on species and site decomposition rates. Typha latifolia leaves from a Canadian bog were placed at the surface and three depths to allow comparisons with northern peatlands. Litterbags were retrieved after 0.5, 1, 2, 3, 4, and 5 years, and mass remaining characterized by an exponential model k value. Surface litter k values (0.12–0.80 y^?1) decreased from early to late successional species; however, decomposition was slower at more waterlogged early successional sites. Buried litter k values (0.04–0.24 y^?1) decreased with depth and increased from early to late successional sites, with Empodisma roots having the slowest rates. Few strong relationships existed between litter quality and decomposition rates. In contrast, water table regime strongly influenced decomposition rates; k values for the “standard” Typha litter decreased exponentially as period of saturation increased, irrespective of site successional status, nutrients, or other factors. Lower water tables in the more aerated later successional sites have led to faster decomposition rates. Ongoing drainage combined with the potential impacts of climate change may increase organic matter decomposition and accelerate carbon release into the atmosphere.     

Anthropogenic Environmental Change, Mosquito-borne Diseases and Human Health in New Zealand

Anthropogenic environmental change is acknowledged as a primary factor in the emergence of diseases. New Zealand’s history since human occupation has been characterized by extensive anthropogenic disturbance and the establishment of numerous exotic species. As a result, highly modified habitats have been created, which, in conjunction with introduced organisms, provide suitable conditions for the establishment of exotic systems likely to lead to outbreaks of mosquito-borne disease. The interactions among some disturbance factors in the New Zealand environment are discussed, and the potential public health implications.     

Impacts of introduced deer and extinct moa on New Zealand ecosystems

There has been considerable ongoing debate about the extent to which the impacts of introduced deer on native vegetation have replaced those of moa, and since the 1980s there have been major changes in thinking about the impacts of deer and ratites on ecosystems. Although it has long been known that deer caused a predictable sequence of changes in forest understorey composition, recent work has shown that the foliage of species preferred by deer contains lower concentrations of fibre ? and decomposes faster ? than avoided species. Analyses of long-term permanent plot data suggest that some preferred species are failing to regenerate in forest types where deer are present. As well as likely altering the long-term biogeochemistry of forest ecosystems, deer have a strong negative effect on the abundance of litter-dwelling macrofauna (most likely through trampling). Estimating the impacts of extinct taxa on an ecosystem has much uncertainty, but recent experiments have shown that extant ratites and deer may have more similar feeding preferences than previously believed. It is likely that moa were important seed dispersers, but this has not been studied for deer in New Zealand. Although collectively the various taxa of deer in New Zealand use all of the habitats utilised by moa, and there is partial overlap in the diets of deer and moa, deer can attain densities and biomasses 100- fold greater than reasonably surmised for moa. We believe that the impacts of introduced deer on ecosystems are markedly different from those of moa. One way to compare the impacts of moa and deer is to use pollen to reconstruct the vegetation at a forested site in recent millennia and evaluate vegetation dynamics during the moa period, following the extinction of moa but prior to the arrival of deer (i.e. the moa gap), and following the arrival of deer. We illustrate the potential of this approach with a soil core from Chester Burn, Murchison Mountains in Fiordland. Five other areas that deserve further research are also identified.     

Impacts of fine sediment addition to tussock, pasture, dairy and deer farming streams in New Zealand

1. Increased fine sediment input caused by agricultural development is expected to act as a stressor for stream ecosystems. In a large‐scale field experiment, we added fine river sand to 50‐m reaches of three second‐order streams in each of four categories of catchment development (ungrazed tussock grasslands, grazed pasture, dairying and deer farming) and measured the responses of macroinvertebrates and aquatic moss. 2. Before addition, fine sediment cover differed between land uses, being lowest in tussock (7%), intermediate in pasture (30%) and dairy (47%) and highest in deer streams (88%). Sediment addition increased cover by one land‐use category (e.g. augmented sediment cover in tussock streams was similar to pre‐existing cover in pasture streams), and cover remained high in impact reaches (compared with controls) throughout the 5‐week experiment. Sediment addition did not change concentrations of phosphate, nitrate and ammonium, which were generally highest in dairy streams and lowest in tussock streams. 3. Aquatic mosses (most common in tussock, absent in dairy and deer), invertebrate density (highest in deer, lowest in tussock), taxon richness (highest in pasture, lowest in deer) and diversity (highest in pasture and tussock, lowest in dairy and deer) all differed between land uses. Sediment addition resulted in reductions of moss cover, invertebrate taxon richness and richness of Ephemeroptera, Plecoptera and Trichoptera in impact relative to control reaches. 4. The impact of sediment addition was strongest in pasture streams where pre‐existing sediment cover was moderate and richness and diversity of the invertebrate community highest. However, even in the already sediment‐rich and species‐poor deer streams, density of one common taxon was reduced significantly by sediment addition, and another two were affected in the same way in dairy streams, the second‐most intense land use. 5. Our experiment has disentangled the impact of sediment addition from other concomitant land‐use effects that could not be reliably distinguished in previous research, which has mainly consisted of correlative studies or unrealistically small‐scale experiments.     

Biological and Health Science courses in New Zealand technical institutes

Argumentation in science is the process of coordinating theory and evidence to justify conclusions. This practice is at the heart of scientific journal writing and communication, but little is known regarding the argument quality of college science majors, the future scientists. Studies on written arguments at the college level have focused primarily on non-majors and upper-level students. To investigate and describe these skills throughout the biology curriculum, majors (n = 243) in four levels of undergraduate biology courses at a public university were assessed using a short, written argument instrument based on a hypothetical data set and scenario. Using Toulmin’s argumentation pattern to assess the instruments for argument aspects and quality, very few differences were found in the scores across course levels. Students were able to generate simple arguments consisting of claim, evidence and reasoning. The ability to provide scientific principles as reasoning to connect evidence and claims was positively correlated with course level. However, advanced argumentation skills, such as creating alternative explanations and rebuttals, were lacking across all course levels. These findings imply the need for explicit attention to argument construction throughout the undergraduate biology curriculum.     

Impacts of Aerial 1080 Poisoning on the Birds of Rangitoto Island, Hauraki Gulf, New Zealand

Bird populations were monitored for one year (October 1990- October 1991) to determine whether the 1080 poison used to eradicate possums and wallabies on Rangitoto Island had had any detrimental effects on them. There was no significant decline in bird numbers recorded immediately after poisoning, with four species increasing in abundance (P <0.001). Twelve months after the operation the abundance of four species had increased significantly (P <0.001). The poisoning does not appear to have had any negative effect on the bird populations of Rangitoto, while the removal of browsing mammals may in future prove to have beneficial effects.     

Smoking Kills,Obesity Disables: A Multistate Approach of the US Health and Retirement Survey

Increasing BMI causes concerns about the consequences for health care. Decreasing cardiovascular mortality has lowered obesity‐related mortality, extending duration of disability. We hypothesized increased duration of disability among overweight and obese individuals. We estimated age‐, risk‐, and state‐dependent probabilities of activities of daily living (ADL) disability and death and calculated multistate life tables, resulting in the comprehensive measure of life years with and without ADL disability. We used prospective data of 16,176 white adults of the Health and Retirement Survey (HRS). Exposures were self‐reported BMI and for comparison smoking status and levels of education. Outcomes were years to live with and without ADL disability at age 55. The reference categories were high normal weight (BMI: 23–24.9), nonsmoking and high education. Mild obesity (BMI: 30–34.9) did not change total life expectancy (LE) but exchanged disabled for disability‐free years. Mild obesity decreased disability‐free LE with 2.7 (95% confidence limits 1.2; 3.2) year but increased LE with disability with 2.0 (0.6; 3.4) years among men. Among women, BMI of 30 to 34.9 decreased disability‐free LE with 3.6 (2.1; 5.1) year but increased LE with disability with 3.2 (1.6;4.8) years. Overweight (BMI: 25–29.9) increases LE with disability for women only, by 2.1 (0.8; 3.3) years). Smoking compressed disability by high mortality. Smoking decreased LE with 7.2 years, and LE with disability with 1.3 (0.5; 2.5) years (men) and 1.4 (0.3; 2.6) years (women). A lower education decreased disability‐free life, but not duration of ADL disability. In the aging baby boom, higher BMI will further increase care dependence.     

Annual patterns in reproduction and perirenal fat of hares (Lepus europaeus) in sub-alpine Canterbury, New Zealand

The aim of this paper was to describe how the age, sex and reproductive state of hares affected the amount of fat found around their left kidney. A total of 2208 hares ( Lepus europaeus ) was shot and autopsied over 13 years from sub-alpine grasslands in Canterbury, South Island, New Zealand. Adult females may be pregnant from July to mid-March. Adult males' testis weights were highest from July to January, and some fertile males may have been present in all months but April. The amount of perirenal fat in adults increased in autumn, peaked in early winter, and decreased thereafter to low levels through spring and summer. Autumn fat deposition in males was not clearly related to reproductive state in individuals, although it coincided with seasonal testicular development. Autumn fat deposition in females may have been caused in part by the cessation of lactation, but, like that in males, the increase was also part of an endogenous pattern. Fat utilization in winter was related to breeding. In males, utilization coincided with reproductive activity and the amount of perirenal fat remained consistently low throughout the breeding season. In females, net fat utilization was associated with lactation but this was balanced to some extent by fat deposition induced by pregnancy. Females simultaneously lactating and pregnant were in finer balance between utilization and deposition. Other factors, such as the number of embryos and the stage of gestation, altered the fat balance in these hares. Fat was also deposited as a 'yolk-sac' in embryos.     

Investigating the Relationship between Ethnic Consciousness,Racial Discrimination and Self-Rated Health in New Zealand

In this study, we examine race/ethnic consciousness and its associations with experiences of racial discrimination and health in New Zealand. Racism is an important determinant of health and cause of ethnic inequities. However, conceptualising the mechanisms by which racism impacts on health requires racism to be contextualised within the broader social environment. Race/ethnic consciousness (how often people think about their race or ethnicity) is understood as part of a broader assessment of the ‘racial climate’. Higher race/ethnic consciousness has been demonstrated among non-dominant racial/ethnic groups and linked to adverse health outcomes in a limited number of studies. We analysed data from the 2006/07 New Zealand Health Survey, a national population-based survey of New Zealand adults, to examine the distribution of ethnic consciousness by ethnicity, and its association with individual experiences of racial discrimination and self-rated health. Findings showed that European respondents were least likely to report thinking about their ethnicity, with people from non-European ethnic groupings all reporting relatively higher ethnic consciousness. Higher ethnic consciousness was associated with an increased likelihood of reporting experience of racial discrimination for all ethnic groupings and was also associated with fair/poor self-rated health after adjusting for age, sex and ethnicity. However, this difference in health was no longer evident after further adjustment for socioeconomic position and individual experience of racial discrimination. Our study suggests different experiences of racialised social environments by ethnicity in New Zealand and that, at an individual level, ethnic consciousness is related to experiences of racial discrimination. However, the relationship with health is less clear and needs further investigation with research to better understand the racialised social relations that create and maintain ethnic inequities in health in attempts to better address the impacts of racism on health.     

Investigating the Relationship between Socially-Assigned Ethnicity,Racial Discrimination and Health Advantage in New Zealand

Background

While evidence of the contribution of racial discrimination to ethnic health disparities has increased significantly, there has been less research examining relationships between ascribed racial/ethnic categories and health. It has been hypothesized that in racially-stratified societies being assigned as belonging to the dominant racial/ethnic group may be associated with health advantage. This study aimed to investigate associations between socially-assigned ethnicity, self-identified ethnicity, and health, and to consider the role of self-reported experience of racial discrimination in any relationships between socially-assigned ethnicity and health.

Methods

The study used data from the 2006/07 New Zealand Health Survey (n = 12,488), a nationally representative cross-sectional survey of adults 15 years and over. Racial discrimination was measured as reported individual-level experiences across five domains. Health outcome measures examined were self-reported general health and psychological distress.

Results

The study identified varying levels of agreement between participants'' self-identified and socially-assigned ethnicities. Individuals who reported both self-identifying and being socially-assigned as always belonging to the dominant European grouping tended to have more socioeconomic advantage and experience less racial discrimination. This group also had the highest odds of reporting optimal self-rated health and lower mean levels of psychological distress. These differences were attenuated in models adjusting for socioeconomic measures and individual-level racial discrimination.

Conclusions

The results suggest health advantage accrues to individuals who self-identify and are socially-assigned as belonging to the dominant European ethnic grouping in New Zealand, operating in part through socioeconomic advantage and lower exposure to individual-level racial discrimination. This is consistent with the broader evidence of the negative impacts of racism on health and ethnic inequalities that result from the inequitable distribution of health determinants, the harm and chronic stress linked to experiences of racial discrimination, and via the processes and consequences of racialization at a societal level.     

Environmental Health Indicators in New Zealand: Drinking Water—A Case Study

This study examines and quantifies the linkages between population health, environmental risks, and its determinants for drinking water in New Zealand using routinely collected data. It was conducted as part of the national environmental health indicators project in New Zealand. The project is based on the World Health Organization’s (WHO) “Environmental and Health Information System” program. Drinking water quality indicators based on the Driving force–Pressure–State–Exposure–Effect–Action (DPSEEA) framework as part of this program were analyzed to validate the model by quantifying the linkages between the indicators. The results of the model suggested over the study period, the state (drinking water quality) and exposure (water access) indicators are significant independent predictors of the effect indicator (waterborne disease rate). This study suggests that routinely collected data can be structured using the DPSEEA framework and tested quantitatively using standard Poisson regression models, thus, illustrating that the model can be used routinely to provide a basis for consideration of the costs and benefits of any interventions to reduce the burden of waterborne disease. Data quality issues need to be considered if such routinely collected data linkages are to be performed for policy purposes. The online version of this article (doi:) contains electronic supplementary material, which is available to authorized users. Supplemental histograms are available in the online appendix.     

Life Cycle Environmental and Cost Impacts of Using an Algal Turf Scrubber to Treat Dairy Wastewater

Using algae to simultaneously treat wastewater and produce energy products has potential environmental and economic benefits. This study evaluates the life cycle energy, greenhouse gas (GHG) emissions, eutrophication potential, and cost impacts of incorporating an algal turf scrubber (ATS) into a treatment process for dairy wastewater. A life cycle inventory and cost model was developed to simulate an ATS treatment system where harvested algae would be used to generate biogas for process heat and electricity generation. Modeling results show that using an ATS significantly reduces eutrophication impacts by reducing chemical oxygen demand, nitrogen, and phosphorus in the wastewater. With low water recirculation rates through the ATS and high algae productivity, inclusion of the ATS results in net energy displacement and a reduction of GHG emissions compared to a system with no ATS. However, if high water recirculation rates are used or if algae biosolids from the digester are dried, the system results in a net increase in energy consumption and GHG emissions. The life cycle treatment cost was estimated to be $1.42 USD per cubic meter of treated wastewater. At this cost, using an ATS would only be cost effective for dairies if they received monetary credits for improved water quality on the order of $3.83 per kilogram of nitrogen and $9.57 per kilogram of phosphorus through, for example, nutrient trading programs.     

Mycotoxin Reduction in Bt Corn: Potential Economic, Health, and Regulatory Impacts

Genetically modified (GM) Bt corn, through the pest protection that it confers, has lower levels of mycotoxins: toxic and carcinogenic chemicals produced as secondary metabolites of fungi that colonize crops. In some cases, the reduction of mycotoxins afforded by Bt corn is significant enough to have an economic impact, both in terms of domestic markets and international trade. In less developed countries where certain mycotoxins are significant contaminants of food, Bt corn adoption, by virtue of its mycotoxin reduction, may even improve human and animal health. This paper describes an integrated assessment model that analyzes the economic and health impacts of two mycotoxins in corn: fumonisin and aflatoxin. It was found that excessively strict standards of these two mycotoxins could result in global trade losses in the hundreds of millions $US annually, with the US, China, and Argentina suffering the greatest losses. The paper then discusses the evidence for Bt corn’s lower levels of contamination of fumonisin and aflatoxin, and estimates economic impacts in the United States. A total benefit of Bt corn’s reduction of fumonisin and aflatoxin in the US was estimated at $23 million annually. Finally, the paper examines the potential policy impacts of Bt corn’s mycotoxin reduction, on nations that are making a decision on whether to allow commercialization of this genetically modified crop.     

Impacts of introduced brown and rainbow trout on benthic invertebrate communities in shallow New Zealand lakes

1. Brown and rainbow trout have been introduced to many inland waters in New Zealand, but research on the impacts on native communities has focused mainly on streams. The purpose of this study was to compare the benthic communities of trout and troutless lakes. Based on previous studies in North America and Europe, we predicted that the benthic biomass, and especially the abundance of large invertebrates, would be lower in lakes with trout as compared to those without. We surveyed the invertebrate fauna of 43 shallow, high‐elevation lakes (26 with and 17 without trout) in four geographic clusters on the central South Island and then conducted a detailed quantitative study of invertebrate biomass and community structure in 12 of these lakes. 2. Benthic community composition and diversity of lakes with and without trout were nearly identical and biomass was as high or higher in the lakes with as without trout. There was no evidence that trout have caused local extinctions of benthic invertebrates. Although the proportional abundance of large‐bodied aquatic was slightly lower in lakes with than without trout, the abundance of several groups of large‐bodied benthic taxa (dragonflies, caddisflies and water bugs) did not differ. 3. Our findings are in contrast to those in North American and Europe where trout introductions into previously troutless lakes have led to declines in the abundance of benthic invertebrates, especially large‐bodied taxa. We propose that the modest effects of trout in New Zealand could be explained by (i) the high areal extent of submergent vegetation that acts as a benthic refuge, (ii) low intensity of trout predation on benthic communities and/or (iii) characteristics of the benthic invertebrates that make them relatively invulnerable to fish predation. 4. Regardless of the relative importance of these hypotheses, our results emphasise that the same invertebrates occurred in all of the lakes, regardless of size, elevation and presence of trout, suggesting habitat generalists dominate the benthic fauna in shallow New Zealand lakes.