Predicting the economic impact of an invasive species on an ecosystem service.

Quantifying the impact of alien invasive species on ecosystem services is an essential step in developing effective practices and policy for invasive species management. Here we develop a stochastic bioeconomic model that enables the economic impact of an invasive pest to be estimated before its arrival, based on relatively poorly specified ecological and economic parameters. We developed the model by using a hypothetical invasion of the varroa bee mite (Varroa destructor) into Australia and the negative flow-on effects that it would have on pollination by reducing honey bee populations, giving rise to a loss of pollination services, reduced crop yields, and additional production costs. If the mite were to continue to be prevented from entering the country over the next 30 years, we estimate that the economic costs avoided would be U.S. $16.4-38.8 million (Aus $21.3-50.5 million) per year. We suggest that current invasion response funding arrangements in Australia, which do not acknowledge these avoided damages, require amendment.     

Coordination geometry of Zn~(2+) on hexagonal turbostratic birnessites with different Mn average oxidation states and its stability under acid dissolution

Hexagonal turbostratic birnessite,with the characteristics of high contents of vacancies,varying amounts of structural and adsorbed Mn~(3+),and small particle size,undergoes strong adsorption reactions with trace metal(TM)contaminants.While the interactions of TM,i.e.,Zn~(2+),with birnessite are well understood,the effect of birnessite structural characteristics on the coordination and stability of Zn~(2+)on the mineral surfaces under proton attack is as yet unclear.In the present study,the effects of a series of synthesized hexagonal turbostratic birnessites with different Mn average oxide states(AOSs)on the coordination geometry of adsorbed Zn~(2+)and its stability under acidic conditions were investigated.With decreasing Mn AOS,birnessite exhibits smaller particle sizes and thus larger specific surface area,higher amounts of layer Mn~(3+)and thus longer distances for the first Mn\O and Mn\Mn shells,but a low quantity of available vacancies and thus low adsorption capacity for Zn~(2+).Zn K-edge EXAFS spectroscopy demonstrates that birnessite with low Mn AOS has smaller adsorption capacity but more tetrahedral Zn(~(IV)Zn)complexes on vacancies than octahedral(~(VI)Zn)complexes,and Zn~(2+)is more unstable under acidic conditions than that adsorbed on birnessite with high Mn AOS.High Zn~(2+)loading favors the formation of~(VI)Zn complexes over~(IV)Zn complexes,and the release of Zn~(2+)is faster than at low loading.These results will deepen our understanding of the interaction mechanisms of various TMs with natural birnessites,and the stability and thus the potential toxicity of heavy metal pollutants sequestered by engineered nano-sized metal oxide materials.     

Groundwater Nutrient Concentrations and Mass Loading Rates at Iowa Golf Courses

Golf courses are often considered by the public to be significant nitrogen (N) and phosphorus (P) nonpoint sources but only limited information exists on nutrient concentrations and loads in golf course groundwater. In this study, we measured N and P concentrations in groundwater and available surface water at six randomly selected Iowa golf courses to assess the loading risk posed by these facilities to groundwater and local rivers. At each course, three shallow monitoring wells were installed, one each on representative tee, fairway, and rough locations. Wells and available surface water were sampled on eight occasions during 2015 and 2016. NO₃‐N concentrations were not detected above 1 mg/L at three of the six courses monitored in this study and the overall mean NO₃‐N concentration in Iowa golf courses was 2.2 mg/L. The mass of NO₃‐N recharged to groundwater averaged 3.3 kg/ha at the six courses, which represents approximately one‐tenth of the NO₃‐N load exported by the watershed that contains the course and represented approximately 0.1 to 8% of the fertilizer N applied. Groundwater orthophosphorus concentrations averaged 0.13 mg/L and were similar to those measured in a variety of settings across Iowa. Study results should prove useful in evaluating nutrient contributions from golf courses in Midwestern states where nutrient reduction strategies are being pursued.     

Motorcycle fuel tanks and pelvic fractures: A motorcycle fuel tank syndrome

Objective: Pelvic injuries are a serious and commonly occurring injury to motorcycle riders involved in crashes, yet there has been limited research investigating the mechanisms involved in these injuries. This study aimed to investigate the mechanisms involved in pelvic injuries to crashed motorcyclists.

Method: This study involved in-depth crash investigation and 2 convenience-based data sets were used. These data sets investigated motorcycle crashes in the Sydney, Newcastle, and Adelaide regions. Participants included motorcycle riders who had crashed either on a public road or private property within the study areas. The mechanism of injury and the type of injuries were investigated.

Results: The most frequent cause of pelvic injuries in crashed motorcyclists was due to contact with the motorcycle fuel tank during the crash (85%). For riders who had come into contact with the fuel tank, the injury types were able to be grouped into 3 categories based on the complexity of the injury. The complexity of the injury appeared to increase with impact speed but this was a nonsignificant trend. The pelvic injuries that did not occur from contact with the fuel tank in this sample differed in asymmetry of loading and did not commonly involve injury to the bladder. They were commonly one-sided injuries but this differed based on the point of loading; however, a larger sample of these injuries needs to be investigated.

Conclusion: Overall improvements in road safety have not been replicated in the amelioration of pelvic injuries in motorcyclists and improvements in the design of crashworthy motorcycle fuel tanks appear to be required.     

Public Space Management: Present and Potential

This paper explores approaches to the management of external public space, both now and in the future. The paper is in five parts. The discussion begins with an exploration of why public space management is universally an important concern by drawing from literature that argues that the quality of public space has declined, and that a greater engagement of the public sector in its management is required. Next, the research methodology is discussed which sought to investigate the management of public space in England as an example of trends and responses that point to a broader international concern. The approach included both a national survey of the state of play in public space management and a series of case studies that sought to explore innovative practice. Third, the results of a national survey are briefly outlined, with discussion following the same structure as the survey itself. Next, the results of detailed interviews with 20 local authority case studies that exhibited interesting or innovative practice in the local management of public space are presented. In a final part, conclusions are drawn which confirm that this is an area of public sector responsibility in need of significant investment and reform, but also that top-down initiatives from national government are beginning to inspire a burgeoning range of local government initiatives below. Therefore, although public space management remains a fragmented area of local government activity, a number of local authorities are beginning to establish a corresponding bottom-up agenda that seems to map a potential way forward for the future.     

Promiscuity in mice is associated with increased vaginal bacterial diversity

Differences in the number of sexual partners (i.e., mating system) have the potential to exert a strong influence on the bacterial communities present in reproductive structures like the vagina. Because this structure serves as a conduit for gametes, bacteria present there may have a pronounced, direct effect on host reproductive success. As a first step towards the identification of the relationship between sexual behavior and potentially pathogenic bacterial communities inhabiting vital reproductive structures, as well as their potential effects on fitness, I sought to quantify differences in bacterial diversity in a promiscuous and monogamous mammal species. To accomplish this, I used two sympatric species of Peromyscus rodents—Peromyscus californicus and Peromyscus maniculatus that differ with regard to the number of sexual partners per individual to test the hypothesis that bacterial diversity should be greater in the promiscuous P. maniculatus relative to the monogamous P. californicus. As predicted, phylogenetically controlled and operational taxonomic unit-based indices of bacterial diversity indicated that diversity is greater in the promiscuous species. These results provide important new insights into the effects of mating system on bacterial diversity in free-living vertebrates, and may suggest a potential cost of promiscuity.     

Individual and collective choice: parallel prospecting and mining in ants

Decision making is of crucial importance in the lives of both animals and humans. How decisions of group members scale up to group decisions is of great interest. Accordingly, we gave homeless ant colonies (n = 67) in three experiments a choice between two nest sites (with small, big or mixed sand grains), each of which had to be excavated to be habitable. Among the colonies that chose only one of the new nest sites, all preferred the ones that could be excavated most easily and quickly. There are interesting parallels between the collective choice of mining sites and the ability of certain ants to select short cuts; both involve positive feedback. However, in this paper, we discuss a mechanism whereby collective co-ordination in the production of social infrastructure can occur in the absence of signalling.     

Preservation of ancient DNA in thermally damaged archaeological bone

Evolutionary biologists are increasingly relying on ancient DNA from archaeological animal bones to study processes such as domestication and population dispersals. As many animal bones found on archaeological sites are likely to have been cooked, the potential for DNA preservation must be carefully considered to maximise the chance of amplification success. Here, we assess the preservation of mitochondrial DNA in a medieval cattle bone assemblage from Coppergate, York, UK. These bones have variable degrees of thermal alterations to bone collagen fibrils, indicative of cooking. Our results show that DNA preservation is not reliant on the presence of intact collagen fibrils. In fact, a greater number of template molecules could be extracted from bones with damaged collagen. We conclude that moderate heating of bone may enhance the retention of DNA fragments. Our results also indicate that ancient DNA preservation is highly variable, even within a relatively recent assemblage from contexts conducive to organic preservation, and that diagenetic parameters based on protein diagenesis are not always useful for predicting ancient DNA survival.     

Microbial stress-response physiology and its implications for ecosystem function

Microorganisms have a variety of evolutionary adaptations and physiological acclimation mechanisms that allow them to survive and remain active in the face of environmental stress. Physiological responses to stress have costs at the organismal level that can result in altered ecosystem-level C, energy, and nutrient flows. These large-scale impacts result from direct effects on active microbes' physiology and by controlling the composition of the active microbial community. We first consider some general aspects of how microbes experience environmental stresses and how they respond to them. We then discuss the impacts of two important ecosystem-level stressors, drought and freezing, on microbial physiology and community composition. Even when microbial community response to stress is limited, the physiological costs imposed on soil microbes are large enough that they may cause large shifts in the allocation and fate of C and N. For example, for microbes to synthesize the osmolytes they need to survive a single drought episode they may consume up to 5% of total annual net primary production in grassland ecosystems, while acclimating to freezing conditions switches Arctic tundra soils from immobilizing N during the growing season to mineralizing it during the winter. We suggest that more effectively integrating microbial ecology into ecosystem ecology will require a more complete integration of microbial physiological ecology, population biology, and process ecology.     

Modeling the influence of precipitation and nitrogen deposition on forest understory fuel connectivity in Sierra Nevada mixed-conifer forest

Climate change models for California's Sierra Nevada predict greater inter-annual variability in precipitation over the next 50 years. These increases in precipitation variability coupled with increases in nitrogen deposition from fossil fuel consumption are likely to result in increased productivity levels and significant increases in forest understory fuel loads. Higher understory plant biomass contributes to fuel connectivity and may increase future fire size and severity in the Sierra Nevada. The objective of this research was to develop and test a model to determine how changing precipitation and nitrogen deposition levels affect shrub and herb biomass production, and to determine how often prescribed fire would be needed to counter increasing fuel loads. Model outputs indicate that under an increasing precipitation scenario significant increases in shrub and herb biomass occur that can be counteracted by decreasing the fire return interval to 10 years. Under a scenario with greater inter-annual variability in precipitation and increased nitrogen deposition, implementing fire treatments at an interval equivalent to the historical range of 15–30 years maintains understory vegetation fuel loads at levels comparable to the control.