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.     

Experimental examination of behavioural interactions between free-ranging wild and domestic canids

The structure of mammalian carnivore communities is strongly influenced by both intraguild competition and predation. However, intraguild interactions involving the world’s most common carnivore, the domestic dog (Canis familiaris), have rarely been investigated. We experimentally examined the behavioural responses of a small canid, the Indian fox (Vulpes bengalensis), to the presence of dogs and dog odours. Resource competition between dogs and Indian foxes is low, so it is unclear whether foxes perceive dogs as interference competitors. To test this, we exposed foxes to neutral, live dog, and animal odour stimuli at food trays, and recorded the time spent at food trays, the amount of food eaten, and vigilance and non-vigilance behaviours. When dogs were visible, foxes continued to visit the food trays, but reduced the amount of time spent and food eaten at those trays. Foxes were more vigilant during dog trials than during neutral and odour trials and also exhibited lower levels of non-vigilance behaviour (resting and playing). In contrast, dog odours did not affect fox foraging and activity. These results show that vigilance/foraging trade-offs due to interference competition can occur between native and domestic carnivores despite low dietary overlap. These negative effects of dogs on a smaller member of the carnivore guild raise conservation concerns, especially for endangered carnivores. In many parts of the world, free-ranging dog densities are high due to human subsidies, and these subsidized predators have the potential to exacerbate the indirect effects of human presence.     

Voluntary information programs and environmental regulation: Evidence from ‘Spare the Air’

This paper assesses whether individuals change their transportation choices in response to ‘Spare the Air’ (STA) advisories, a public voluntary information program in the San Francisco Bay Area that elicits reductions in ozone-producing activities. Since STAs are issued when ozone levels are predicted to exceed a particular threshold, we use a regression discontinuity design to identify the effect of STAs. We also use traffic conditions in Southern California, an area without STAs, to estimate difference-in-differences models. The results suggest that STAs reduce traffic volume and slightly increase the use of public transit, supporting a potential role for voluntary information programs that directly target individuals as a means for improving local air quality.     

Principles and application of an in vivo swine assay for the determination of arsenic bioavailability in contaminated matrices

The assessment of arsenic (As) bioavailability from contaminated matrices is a crucial parameter for reducing the uncertainty when estimating exposure for human health risk assessment. In vivo assessment of As utilising swine is considered an appropriate model for human health risk assessment applications as swine are remarkably similar to humans in terms of physiology and As metabolism. While limited in vivo As bioavailability data is available in the literature, few details have been provided regarding technical considerations for performing in vivo assays. This paper describes, with examples, surgical, experimental design and analytical issues associated with performing chronic and acute in vivo swine assays to determine As bioavailability in contaminated soil and food.     

Distinguishing stressors acting on land bird communities in an urbanizing environment

Urbanization has profound influences on ecological communities, but our understanding of causal mechanisms is limited by a lack of attention to its component stressors. Published research suggests that at landscape scales, habitat loss and fragmentation are the major drivers of community change, whereas at local scales, human activity and vegetation management are the primary stressors. Little research has focused on whether urbanization stressors may supplant natural factors as dominant forces structuring communities. We used model selection to determine the relative importance of urban development, human activity, local and landscape vegetation, topography, and geographical location in explaining land bird species richness, abundance, and dominance. We analyzed the entire community and groups of species based on ecological characteristics, using data collected in remnant forests along a gradient of urban development in the Lake Tahoe basin, California and Nevada, USA. Urbanization stressors were consistently among the principal forces structuring the land bird community. Strikingly, disturbance from human activity was the most important factor for richness in many cases, surpassing even habitat loss from development. Landscape-scale factors were consistently more important than local-scale factors for abundance. In demonstrating considerable changes in land bird community structure, our results suggest that ecosystem function in urban areas may be severely compromised. Such changes compel local- and landscape-scale management, focused research, and long-term monitoring to retain biodiversity in urban areas to the extent possible.