Mummies and masquerades: English and Caribbean connections

The composite mumming play script that the Ecclesfield-based Victorian children's author Juliana Horatia Ewing published in 1884 found its way to St. Kitts and Nevis in the Caribbean, where it was it was taken up enthusiastically by the black population as one of its Christmas Sports. The Mummies continue to act (and dance) to this day. Economic migrants took the Christmas Sports in turn to the Dominican Republic, in particular around the town of San Pedro de Macoris, where the performers recently gained a UNESCO Cultural Heritage Award. This paper derives from a presentation based around two videos, presented here as story boards. Millington introduces Ewing's play, and footage of the St Kitts Mummies and the Bull Play filmed by Joan McMurray. James continues the story by introducing footage of the related tradition from the Dominican Republic called the Wild Indians in English and Los Guloyas (the Goliaths) in Spanish

An Agent-Based Model of Mediterranean Agricultural Land-Use/Cover Change for Examining Wildfire Risk

Humans have a long history of activity in Mediterranean Basin landscapes. Spatial heterogeneity in these landscapes hinders our understanding about the impacts of changes in human activity on ecological processes, such as wildfire. The use of spatially-explicit models that simulate processes at fine scales should aid the investigation of spatial patterns at the broader, landscape scale. Here, we present an agent-based model of agricultural land-use decision-making to examine the importance of land tenure and land use on future land cover. The model considers two 'types' of land-use decision-making agent with differing perspectives; 'commercial' agents that are perfectly economically rational, and 'traditional' agents that represent part-time or 'traditional' farmers that manage their land because of its cultural, rather than economic, value. The structure of the model is described and results are presented for various scenarios of initial landscape configuration. Land-use/cover maps produced by the model are used to examine how wildfire risk changes for each scenario. Results indicate that land tenure configuration influences trajectories of land use change. However, simulations for various initial land-use configurations and compositions converge to similar states when land-tenure structure is held constant. For the scenarios considered, mean wildfire risk increases relative to the observed landscape. Increases in wildfire risk are not spatially uniform however, varying according to the composition and configuration of land use types. These unexpected spatial variations in wildfire risk highlight the advantages of using a spatially-explicit agent-based model of land use/cover change.Land Use/Cover Change, Land Tenure, Wildfire, Mediterranean-Type Ecosystem, Agriculture, Spatial Heterogeneity

Assessing the quality of land system models: moving from valibration to evaludation

Reviews suggest that evaluation of land system models is largely inadequate, with undue reliance on a vague concept of validation. Efforts to improve and standardise evaluation practices have so far had limited effect. In this article we examine the issues surrounding land system model evaluation and consider the relevance of the TRACE framework for environmental model documentation. In doing so, we discuss the application of a comprehensive range of evaluation procedures to existing models, and the value of each specific procedure. We develop a tiered checklist for going beyond what seems to be a common practice of ‘valibration’ (the repeated variation of model parameter values to achieve agreement with data) to achieving ‘evaludation’ (the rigorous, broad-based assessment of model quality and validity). We propose the Land Use Change – TRACE (LUC-TRACE) model evaludation protocol and argue that engagement with a comprehensive protocol of this kind (even if not this particular one) is valuable in ensuring that land system model results are interpreted appropriately. We also suggest that the main benefit of such formalised structures is to assist the process of critical thinking about model utility, and that the variety of legitimate modelling approaches precludes universal tests of whether a model is ‘valid’. Evaludation is therefore a detailed and subjective process requiring the sustained intellectual engagement of model developers and users

Local winter deer density: Effects of forest structure and snow in a managed forest landscape

*Background/Questions/Methods*
White-tailed deer (_Odocoileus virginianus_) are a ‘keystone herbivore’ with the potential to cause tree regeneration failure and greatly affect vegetation dynamics, stand structure and ecological function of forests across eastern North America. In northern mixed conifer-hardwood forests, local winter-time deer populations are dependent on habitat characterized by patterns of forest cover that provide shelter from snow and cold temperatures (lowland conifer stands) in close proximity to winter food (deciduous hardwood stands). Stand structure may also influence winter spatial deer distribution. Consequently, modification of forest cover patterns and stand structure by timber harvesting will affect local spatial deer distributions, with potential ecological and economic consequences. Here, we ask if forest cover pattern and stand structure, and their interactions with snow depth, can explain winter deer density in the managed forests of the central Upper Peninsula of Michigan, USA. For each local winter deer density estimate (from fecal pellet counts) we calculate stand-level characteristics for surrounding ‘landscapes of influence’ of radius 200 m. For these data, and modeled snow depth estimates, we use multivariate techniques to produce predictive models and to identify the most important factors driving local deer densities across our 400,000 ha study area. 

*Results/Conclusions*
Distance to the nearest conifer stand consistently explains the most variance in univariate regression models. Deer densities are highest near lowland conifer stands in areas where mean hardwood tree diameter-at-breast-height is low. Multiple regression models including these factors explain 22% of variance in deer density and have up to a 65% chance of correctly ranking a site’s deer density (relative to other sites within our study area). We use model ensembles to produce maps of estimated deer density (and associated uncertainty) for a subset of our study area and show how managers might use these maps to aid co-management of deer and forest regeneration. Our results highlight the importance of local and regional factors (forest cover-type pattern, stand structure, climate) on winter white-tailed deer density in managed hardwood-conifer forests. Use of these results, and the simulation model being developed, will help identify management practices that can decrease deer impacts and ensure the ecological and economic sustainability of forests in which deer browse is proving problematic for tree regeneration.
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Evaluating explanations of land cover change using approximate Bayesian Computation

The ecology of the Mediterranean region today is the product of thousands of years of human intervention, combined with the effects of climatic change on its flora, and natural disturbance arising from its active fire regim e. Understanding the complex ways in which anthropogenic land- cover change, climate, and fire interact with each other could help guide public policy and land management decision- making, especially important to ensure sustainability in an uncertain future of climate change. A fruitful step in this endeavour will be to explain changes to landscape- scale vegetation ecology arising from the time when humans first began to compete with fire as a source of ecological disturbance 10,000 years ago – the agricultur al revolution. Paleoecological data provide a means to study ecosystem change in the distant past, and over timescales longer than a human lifetime. In particular, analysis of how the abundance of pollen produced by different plant functional types has changed over time can tell us much about the evolution of the composition of those functional types in the land- cover around a study site. Pollen time series can be viewed as fingerprints of the interacting processes of anthropogenic land- cover change, fire a nd ecological succession, against the backdrop of a changing climate. However, no amount of scrutiny of the data alone can elucidate the causal role each of the interacting factors had in creating them. We have developed a model which integrates theoretica l understanding of ecological and anthropogenic processes via an agent -based modelling framework. By simulating both natural and anthropogenic processes and allowing them to interact with each other in a spatially explicit virtual landscape, we can generat e dynamic pictures of landscapes evolving in time which are consistent with socio- ecological theory. However, as scientists we must be vigilant in our reporting of uncertainty about our models. Historical sciences provide a unique challenge in this regard, since theories cannot be tested by direct experimentation. In this talk, I will discuss the use of approximate Bayesian computation (ABC) as a means to unite acausal paleoecological data with a socio- ecological simulation model which encodes causal hypoth eses about Neolithic land -cover change, but whose likeness to reality is uncertain. ABC will be considered as a tool to support inference about which models best explain available empirical data, as well as indicating which aspects of those models are most uncertain

Suppression of adaptive immunity to heterologous antigens during Plasmodium infection through hemozoin-induced failure of dendritic cell function

BACKGROUND: Dendritic cells (DCs) are central to the initiation and regulation of the adaptive immune response during infection. Modulation of DC function may therefore allow evasion of the immune system by pathogens. Significant depression of the host's systemic immune response to both concurrent infections and heterologous vaccines has been observed during malaria infection, but the mechanisms underlying this immune hyporesponsiveness are controversial. RESULTS: Here, we demonstrate that the blood stages of malaria infection induce a failure of DC function in vitro and in vivo, causing suboptimal activation of T cells involved in heterologous immune responses. This effect on T-cell activation can be transferred to uninfected recipients by DCs isolated from infected mice. Significantly, T cells activated by these DCs subsequently lack effector function, as demonstrated by a failure to migrate to lymphoid-organ follicles, resulting in an absence of B-cell responses to heterologous antigens. Fractionation studies show that hemozoin, rather than infected erythrocyte (red blood cell) membranes, reproduces the effect of intact infected red blood cells on DCs. Furthermore, hemozoin-containing DCs could be identified in T-cell areas of the spleen in vivo. CONCLUSION: Plasmodium infection inhibits the induction of adaptive immunity to heterologous antigens by modulating DC function, providing a potential explanation for epidemiological studies linking endemic malaria with secondary infections and reduced vaccine efficacy

Toward quantification of the feasible potential of land-based carbon dioxide removal

Global climate-change overshoot scenarios, where warming exceeds Paris Agreement limits before being brought back down, are highly dependent on land-based carbon dioxide removal (CDR). In the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), such scenarios are supported by optimistic global assessments of the technical and economic potential for land-based CDR. However, a further type of potential—the ‘‘feasible’’ potential, which includes socio-cultural, environmental, and institutional factors—is noted in the AR6 but not quantified. Here, we set out research frameworks to work toward quantification of this feasible potential. We first argue that quantifying the feasible potential will substantiallyreduce current assessed CDR potential. Second, we demonstrate how transdisciplinary methods are improving understanding of feasibility constraints on land-based CDR. Third, we explore frameworks for synthesizing these advances during the next IPCC assessment process. We conclude that the research community should carefully consider the use of techno-economic CDR assessments in evidence for policymaker