Practical guidelines for modelling post-entry spread in invasion ecology

In this article we review a variety of methods to enable understanding and modelling the spread of a pest or pathogen post-entry. Building upon our experience of multidisciplinary research in this area, we propose practical guidelines and a framework for model development, to help with the application of mathematical modelling in the field of invasion ecology for post-entry spread. We evaluate the pros and cons of a range of methods, including references to examples of the methods in practice. We also show how issues of data deficiency and uncertainty can be addressed. The aim is to provide guidance to the reader on the most suitable elements to include in a model of post-entry dispersal in a risk assessment, under differing circumstances. We identify both the strengths and weaknesses of different methods and their application as part of a holistic, multidisciplinary approach to biosecurity research

Tropical cyclones and the ecohydrology of Australia's recent continental-scale drought

The Big Dry, a recent drought over southeast Australia, began around 1997 and continued until 2011. We show that between 2002-2010, instead of a localized drought, there was a continent-wide reduction in water storage, vegetation and rainfall, spanning the northwest to the southeast of Australia. Trends in water storage and vegetation were assessed using Gravity Recovery and Climate Experiment (GRACE) and Normalized Difference Vegetation Index (NDVI) data. Water storage and NDVI are shown to be significantly correlated across the continent and the greatest losses of water storage occurred over northwest Australia. The frequency of tropical cyclones over northwest Australia peaked just prior to the launch of the GRACE mission in 2002. Indeed, since 1981, decade-scale fluctuations in tropical cyclone numbers coincide with similar variation in rainfall and vegetation over northwest Australia. Rainfall and vegetation in southeast Australia trended oppositely to the northwest prior to 2001. Despite differences between the northwest and southeast droughts, there is reason to believe that continental droughts may occur when the respective climate drivers align

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Optimal conservation investment for a biodiversity-rich agricultural landscape

This study develops a theoretical and empirical framework for optimal conservation planning using satellite land cover data and economic data from a farm survey. A case study is presented for a region within the South-west Australia Biodiversity Hotspot (Nature 403, 853). This Biodiversity Hotspot is a focus for conservation investment as it combines a relatively high level of biodiversity with severe threat to the biodiversity from agriculture. The conservation planning model developed determines the optimal set of bush fragments for conservation. This model can also be used to assess the trade-off between the budget and a vegetation species metric. Results from the case study show that, without an effective conservation scheme that at least fences fragments, significant plant biodiversity losses will occur in the North East Wheatbelt Regional Organisation of Councils region of the WA wheatbelt over a 10-year period. A perfect price discriminating auction scheme could reduce the costs of conservation by around 17 per cent relative to a fixed-payment scheme; however, a fixed payment on outcome (measured as change in the species metric) scheme represents a viable second-best alternative, to a conservation auction, where conservation spending is spatially targeted

To Save or Savour: A Review of Wine Investment

It has been argued that adding wine to an investment portfolio provides a diversification benefit. There is not, however, agreement on how the return to wine should be estimated. Nor is there agreement on a standard approach to test for a diversification benefit. By considering different approaches to estimating the return to wine and testing for a diversification benefit it is shown that claims wine provides a diversification benefit should be treated with caution

The importance of tree cover and neighbourhood parks in determining urban property values

This paper presents a spatially explicit analysis of the contribution of urban trees and parks to residential property values. We estimated the effects of structural, neighbourhood, and environmental variables, including tree cover, on sale price of single-family homes in Perth using a generalized spatial two-stage least-squares model. The spatial model results indicate that, among other structural and neighbourhood variables, the proportion of tree cover on street verges (public space) and the extent and proximity of neighbourhood parks attract significant price premiums in the Perth housing market. However, we failed to find any evidence of impact of the tree cover on property (private space) on its sale price. Further, we find that the parameter estimate for street tree cover obtained from spatial hedonic model is half the size of estimate obtained from ordinary hedonic model, thus indicating importance of spatially explicit hedonic model on implicit price estimation. Based on the spatial hedonic model, it is estimated that 10% increase in tree cover on street verge above the median cover of 19.66% increases the median house price (AU$765,000) by about AU$ 3,250. Our findings have implications on managing and developing urban forest cover along the streets in Perth for both private and public benefits

Contracts for Grain Biosecurity and Grain Quality

The export of grain from Western Australia depends upon a grain supply network that takes grain from farm to port through Cooperative Bulk Handling receival and storage sites. The ability of the network to deliver pest free grain to the port and onto ship depends upon the quality of grain delivered by farmers and the efficacy of phosphine based fumigation in controlling stored grain pests. Phosphine fumigation is critical to the grain supply network because it is the cheapest effective fumigant. In addition, it is also residue free. Unfortunately, over time, common stored-grain pests have evolved to develop resistance to phosphine and there is a risk that phosphine will become less effective and may need to be replaced with more expensive alternative fumigants. Currently the alternative fumigants will involve substantial capital investment or leave residues in the grain which may restrict grain exports. There is some evidence that phosphine resistance develops on farm due to inadequate biosecurity management. As a first step to analysing this problem, this paper considers the design of farm biosecurity contracts using a principal-agent approach

Area-Wide Management of Fruit-Flies: What are the Costs and the Benefits?

Increasing volumes and speed of agricultural trade and the opening of new markets for agricultural products create greater challenges to systems established to protect countries from invasive organisms that can be harmful to human and animal health, crops and natural environments. In reaction to the threat of exotic pests and diseases, the World Trade Organization recognises the right of country members to protect themselves from the risks posed by exotic pests and diseases through the application of Sanitary and Phytosanitary (SPS) measures. One possible response from exporting countries facing SPS trade barriers is to obtain pest-free area (PFA) certification. While large benefits can potentially be achieved from greater access to world markets through the establishment and maintenance of a PFA, certification can be expensive. This paper aims to identify a theoretical framework on which to base the cost benefit analysis and the costs and benefits to be measured, from which a methodology for measuring costs and benefits may be developed. The literature relevant to analysing PFAs reveals that cost benefit analysis of the establishment of PFAs incorporate complex links between the economic aspects of this type of pest management and the biological characteristics of the pest or disease targeted and its environment

Valuing public and private urban tree canopy cover

In this paper, we estimate the effect of tree canopy cover on sales price of urban residential properties in Perth, Western Australia. Using a data set of 5606 single family homes sold in 2009 and a spatial hedonic model with three spatial effects – spatial-temporal lag on dependent variable, spatial error, and spatially lagged independent variables – we estimated the location-specific effect of tree canopy cover. Tree canopy cover increases the property value when located on adjacent public space, but decreases the value when it is on own property and on the adjacent property within 20 m of property boundary. The results are suggestive that council urban tree planting programs provide significant private benefits to homeowners

Surveillance in Fruit Flies Free Areas: An Economic Analysis

Increasing pressure to reduce the use of pre and post-harvest treatment chemicals to control insect pests has led to calls for alternative control methods. As a result, the implementation of area-wide management of pests could be developed as either an alternative to chemicals or as a means of reducing pesticide use. However, maintaining an area-wide management programme can be expensive as it requires the execution of surveillance activities, exclusion measures and contingency plans for a rapid eradication response in the case of a pest outbreak. A sound benefit-cost analysis is an essential starting point to measure gains from research and development into improved methods of surveillance and exclusion. This paper presents a study of the costs of surveillance measures. We applied our model to the Fruit Fly Exclusion Zone (FFEZ) in South Eastern Australia