Estimating the Social Welfare Effects of New Zealand Apple Imports

This paper provides a demonstration of how a comprehensive economic framework, which takes into account both the gains from trade and the costs of invasive species outbreaks, can inform decision-makers when making quarantine decisions. Using the theoretical framework developed in Cook and Fraser (2008) an empirical estimation is made of the economic welfare consequences for Australia of allowing quarantine-restricted trade in New Zealand apples to take place. The results suggest the returns to Australian society from importing New Zealand apples are likely to be negative. The price differential between the landed product with SPS measures in place and the autarkic price is insufficient to outweigh the increase in expected damage resulting from increased fire blight risk. As a consequence, this empirical analysis suggests the net benefits created by opening up this trade are marginal.International Relations/Trade,

Predicting Invasive Fungal Pathogens Using Invasive Pest Assemblages: Testing Model Predictions in a Virtual World

Predicting future species invasions presents significant challenges to researchers and government agencies. Simply considering the vast number of potential species that could invade an area can be insurmountable. One method, recently suggested, which can analyse large datasets of invasive species simultaneously is that of a self organising map (SOM), a form of artificial neural network which can rank species by establishment likelihood. We used this method to analyse the worldwide distribution of 486 fungal pathogens and then validated the method by creating a virtual world of invasive species in which to test the SOM. This novel validation method allowed us to test SOM's ability to rank those species that can establish above those that can't. Overall, we found the SOM highly effective, having on average, a 96–98% success rate (depending on the virtual world parameters). We also found that regions with fewer species present (i.e. 1–10 species) were more difficult for the SOM to generate an accurately ranked list, with success rates varying from 100% correct down to 0% correct. However, we were able to combine the numbers of species present in a region with clustering patterns in the SOM, to further refine confidence in lists generated from these sparsely populated regions. We then used the results from the virtual world to determine confidences for lists generated from the fungal pathogen dataset. Specifically, for lists generated for Australia and its states and territories, the reliability scores were between 84–98%. We conclude that a SOM analysis is a reliable method for analysing a large dataset of potential invasive species and could be used by biosecurity agencies around the world resulting in a better overall assessment of invasion risk

Biosecurity and Yield Improvement Technologies Are Strategic Complements in the Fight against Food Insecurity

The delivery of food security via continued crop yield improvement alone is not an effective food security strategy, and must be supported by pre- and post-border biosecurity policies to guard against perverse outcomes. In the wake of the green revolution, yield gains have been in steady decline, while post-harvest crop losses have increased as a result of insufficiently resourced and uncoordinated efforts to control spoilage throughout global transport and storage networks. This paper focuses on the role that biosecurity is set to play in future food security by preventing both pre- and post-harvest losses, thereby protecting crop yield. We model biosecurity as a food security technology that may complement conventional yield improvement policies if the gains in global farm profits are sufficient to offset the costs of implementation and maintenance. Using phytosanitary measures that slow global spread of the Ug99 strain of wheat stem rust as an example of pre-border biosecurity risk mitigation and combining it with post-border surveillance and invasive alien species control efforts, we estimate global farm profitability may be improved by over US$4.5 billion per annum

Modelling the Arrival of Invasive Organisms via the International Marine Shipping Network: A Khapra Beetle Study

<div><p>Species can sometimes spread significant distances beyond their natural dispersal ability by anthropogenic means. International shipping routes and the transport of shipping containers, in particular are a commonly recognised pathway for the introduction of invasive species. Species can gain access to a shipping container and remain inside, hidden and undetected for long periods. Currently, government biosecurity agencies charged with intercepting and removing these invasive species when they arrive to a county’s border only assess the most immediate point of loading in evaluating a shipping container’s risk profile. However, an invasive species could have infested a container previous to this point and travelled undetected before arriving at the border. To assess arrival risk for an invasive species requires analysing the international shipping network in order to identify the most likely source countries and the domestic ports of entry where the species is likely to arrive. We analysed an international shipping network and generated pathway simulations using a first-order Markov chain model to identify possible source ports and countries for the arrival of Khapra beetle (<em>Trogoderma granarium</em>) to Australia. We found Kaohsiung (Taiwan) and Busan (Republic of Korea) to be the most likely sources for Khapra beetle arrival, while the port of Melbourne was the most likely point of entry to Australia. Sensitivity analysis revealed significant stability in the rankings of foreign and Australian ports. This methodology provides a reliable modelling tool to identify and rank possible sources for an invasive species that could arrive at some time in the future. Such model outputs can be used by biosecurity agencies concerned with inspecting incoming shipping containers and wishing to optimise their inspection protocols.</p> </div

No short-term impact of honey bees on the reproductive success of an Australian native bee

The European honey bee was introduced to Australia 180 years ago and feral populations now occupy most coastal environments. Although much debate has taken place regarding the possible impact of honey bees on Australian native bees, there has been little direct research. This study presents the results of a replicated Before-After Control-Impact (BACI) experiment simulating the putative impact of feral honey bees on an undescribed species of Australian solitary bee (Megachile sp. M323/F367). Although a large resource overlap occurred between the two species, there was no significant change in the reproductive success of the native bee. The realised precision of the experiment was assessed and showed appropriate sensitivity for three important reproductive variables. The native bee, being better adapted to the high summer temperatures experienced during the period of this experiment, may be able to withstand honey bee competition

Port by port rankings.

<p>Top ten ranked source ports for Khapra beetle introduction to the ten most threatened Australian ports (see the rankings of Australian ports in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone-0044589-t002" target="_blank">Table 2</a>). For the full lists see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s003" target="_blank">Tables S3</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s004" target="_blank">S4</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s005" target="_blank">S5</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s006" target="_blank">S6</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s007" target="_blank">S7</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s008" target="_blank">S8</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s009" target="_blank">S9</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s010" target="_blank">S10</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s011" target="_blank">S11</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044589#pone.0044589.s012" target="_blank">S12</a>.</p>*<p>denotes the relative pest’s arrival rate versus the avergae <i>φ_ij</i> values for all network locations ( = 0.00259).</p

Can global weed assemblages be used to predict future weeds?

Predicting which plant taxa are more likely to become weeds in a region presents significant challenges to both researchers and government agencies. Often it is done in a qualitative or semi-quantitative way. In this study, we explored the potential of using the quantitative self-organising map (SOM) approach to analyse global weed assemblages and estimate likelihoods of plant taxa becoming weeds before and after they have been moved to a new region. The SOM approach examines plant taxa associations by analysing where a taxon is recorded as a weed and what other taxa are recorded as weeds in those regions. The dataset analysed was extracted from a pre-existing, extensive worldwide database of plant taxa recorded as weeds or other related status and, following reformatting, included 187 regions and 6690 plant taxa. To assess the value of the SOM approach we selected Australia as a case study. We found that the key and most important limitation in using such analytical approach lies with the dataset used. The classification of a taxon as a weed in the literature is not often based on actual data that document the economic, environmental and/or social impact of the taxon, but mostly based on human perceptions that the taxon is troublesome or simply not wanted in a particular situation. The adoption of consistent and objective criteria that incorporate a standardized approach for impact assessment of plant taxa will be necessary to develop a new global database suitable to make predictions regarding weediness using methods like SOM. It may however, be more realistic to opt for a classification system that focuses on the invasive characteristics of plant taxa without any inference to impacts, which to be defined would require some level of research to avoid bias from human perceptions and value systems

A geographical distribution of the Khapra beetle arrival potential to Australian ports.

<p>(A) Potential of foreign ports to be the source of Khapra beetle arrival at an Australian port, (B) The potential of Australian ports to receive Khapra beetle from foreign ports infested with the pest.</p