Models of plant migration based on estimates of biological parameters severely underestimate the rate of spread when compared to empirical estimates of plant migration rates. This is disturbing, since an ability to predict migration and colonization rates is needed for predicting how native species will distribute themselves in response to habitat loss and climate change and how rapidly invasive species will spread. Part of the problem is the difficulty of formally including rare long-distance dispersal events in spread models. In this article, we explore the process of making predictions about plant migration rates. In particular, we examine the links between data, statistical models, and ecological predictions. We fit mixtures of Weibull distributions to several dispersal data sets and show that statistical and biological criteria for selecting the most appropriate statistical model conflict. Fitting a two-component mixture model to the same data increases the spread-rate prediction by an average factor of 4.5. Data limit our ability to fit more components. Using simulations, we show that a small proportion (0.001) of seeds moving long-distances (1-10 km) can lead to an order of magnitude increase in predicted spread rate. The analysis also suggests that most existing data sets on dispersal will not resolve the problem; more effort needs to be devoted to collecting data on long-distance dispersal. Although dispersal had the strongest effect on the predicted spread rate, we showed that dispersal interacts strongly with plant life history, disturbance, and habitat loss in influencing the predicted rate of spread. The importance of these interactions means that an approach that integrates local and long-distance dispersal with plant life history, disturbance, and habitat availability is essential for predicting migration rates.

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In the last 15 years, agri-environmental programmes in Australia have been underpinned by a neoliberal regime of governing which seeks to foster participation and 'bottom-up' change at the regional level at the same time as encouraging farmers to become entrepreneurial and improve their productivity and environmental performance without government interference. However, while experiencing a degree of success in terms of farmer involvement, considerable tensions are evident in such programmes. Drawing on an 'analytics of governmentality', this paper argues that while current agri-environmental programmes enable authorities to combine often competing and contradictory imperatives under the rubric of single political problems-what has been termed hybrid forms of governing-it also contributes to the continuing failure of these programmes to achieve their desired effects. As a consequence, neoliberal forms of governing tend to be characterised by experimentation with a range of governmental technologies in order to make programmes workable in practice. We explore two different types of technologies-standards schemes and direct government regulation-that have emerged in recent years, and how these have sought to address the limitations evident in 'participatory' programmes. The paper concludes by arguing that while these initiatives seek to encourage farmer compliance in seemingly divergent ways, their capacity to be workable, and have broader effects, in practice will depend upon their capacity to manage the competing imperatives of environmental degradation, capital accumulation and private property rights. r

Harmonisation of disease management practices across global space and the devolution of responsibility to a broader range of actors are two increasingly important approaches for ordering biosecurity governance. While these forms of ordering have been examined individually, the social science biosecurity literature provides limited insights into how they interact and interfere with one another, and the consequences for biosecurity implementation. This paper draws upon an institutional logics approach to examine the different and competing logics through which government agencies, industry bodies and farming enterprises engage in biosecurity. It focuses specifically on the ways in which these logics pose challenges for harmonisation of biosecurity as well as create alternative spaces of negotiation for making life safe. Through the analysis of policy documents and semi-structured interviews with government and industry stakeholders, as well as with beef producers, we identify three institutional logics being the neoliberal, productivist and agrarian logics. We argue that the existence of multiple logics poses significant challenges for efforts to achieve improved harmonisation of biosecurity in an environment of devolved responsibility to industry, farming bodies and producers. In this context, greater emphasis by stakeholders on the productivist logic holds the most potential for improving biosecurity implementation in that it works with existing agricultural circulations and flows, and with producers' herd health practices.

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Intemational trade poses a serious and growing threat to biosecurity through the introduction of invasive pests and disease: these have adverse impacts on plant and animal health and public goods such as biodiversity, as well as food production capacity. While intemational govemmental bodies such as the World Trade Organization (WTO) recognise such threats, and permit govemments to protect human, animal, and plant life or health, such measures must not be applied in a way that is restrictive to trade. This raises a fundamental (but little-examined) tension between effective biosecurity govemance and the neoliberal priorities of intemational trade. In this paper we examine how such tensions play out in the different politieal and geographical contexts of Australia and the United Kingdom. A comparative approach enables close scrutiny of how trade liberalisation and biosecurity are coconstituted as compatible objectives as well as the tensions and contradictions involved in making these domains a single govemable problem. The comparative analysis draws attention to the policy challenges facing Australia and the UK in goveming national biosecurity in a neoliberal world. These challenges reveal a coiriplex geopolitics in the ways in which bioseeurity is practised, institutionalised, and debated in each country, with implications for which pests and diseases are defmed as threats and, therefore, which commodities are permitted to move across national borders. Despite efforts by the WTO to govem biosecurity as a technical matter of risk assessment and management, and to harmonise national practices, we contend that actual biosecurity practices continue to diverge between states depending on perceptions of risk and hazard, both to agricultural production and to rural environments as a whole, as well as unresolved tensions between intemationalised neoliberalism and domestic concems.

International efforts to prevent the spread of biological threats to agro-food production are increasingly being devolved from national governments to farming industries and farmers. Previous research has highlighted the farm-level and institutional challenges in engaging farmers in biosecurity. However, little is known sociologically about what farmers already know and do to manage disease risk, and specifically how they practice biosecurity. This article addresses this issue through the application of theoretical work on the choreography of care. Drawing from a qualitative study of biosecurity in the Australian beef industry, we argue that farmers' localised practices of caring for their herd health and farm are crucial in making biosecurity workable. These practices take two key forms: skilled craftwork, through which farmers construct and hold together different objects and elements of care; and fluid engineering, which involves efforts to construct barriers for separating on-farm practices of care from perceived off-farm disease risks. In engaging in these care practices, farmers make an important contribution to national livestock biosecurity principles and practices. We argue that greater recognition of localised practices of biosecure care may provide the basis for engaging farmers more effectively in a devolved form of biosecurity governance.