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Michael A. Mccarthy - One of the best experts on this subject based on the ideXlab platform.
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Optimal surveillance strategy for Invasive Species Management when surveys stop after detection.
Ecology and Evolution, 2014Co-Authors: Gurutzeta Guillera-arroita, Cindy E. Hauser, Michael A. MccarthyAbstract:Invasive Species are a cause for concern in natural and economic systems and require both monitoring and Management. There is a trade-off between the amount of resources spent on surveying for the Species and conducting early Management of occupied sites, and the resources that are ultimately spent in delayed Management at sites where the Species was present but undetected. Previous work addressed this optimal resource allocation problem assuming that surveys continue despite detection until the initially planned survey effort is consumed. However, a more realistic scenario is often that surveys stop after detection (i.e., follow a “removal” sampling design) and then Management begins. Such an approach will indicate a different optimal survey design and can be expected to be more efficient. We analyze this case and compare the expected efficiency of Invasive Species Management programs under both survey methods. We also evaluate the impact of mis-specifying the type of sampling approach during the program design phase. We derive analytical expressions that optimize resource allocation between monitoring and Management in surveillance programs when surveys stop after detection. We do this under a scenario of unconstrained resources and scenarios where survey budget is constrained. The efficiency of surveillance programs is greater if a “removal survey” design is used, with larger gains obtained when savings from early detection are high, occupancy is high, and survey costs are not much lower than early Management costs at a site. Designing a surveillance program disregarding that surveys stop after detection can result in an efficiency loss. Our results help guide the design of future surveillance programs for Invasive Species. Addressing program design within a decision-theoretic framework can lead to a better use of available resources. We show how Species prevalence, its detectability, and the benefits derived from early detection can be considered.
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Prevent, search or destroy? A partially observable model for Invasive Species Management
Journal of Applied Ecology, 2014Co-Authors: Tracy M. Rout, Joslin L. Moore, Michael A. MccarthyAbstract:Summary: The extensive impact of Invasive Species has motivated a growing field of research combining ecological and economic models to find cost-effective Management strategies. Ecological systems are rarely perfectly observable, meaning decision-makers are usually uncertain about the current extent of an infestation and even whether an Invasive Species is present or absent. We show how to account for this uncertainty when providing decision support for Invasive Species Management. We constructed the first partially observable model to analyse the trade-off between all three facets of Invasive Species Management: quarantine, surveillance and control. We use a partially observable Markov decision process (POMDP) to determine how to allocate resources between these actions when the extent of an invasion is uncertain. We use a case study of potential black rat Rattus rattus invasion on Barrow Island, Western Australia. Our model shows it is often better to manage based on an uncertain belief in Species presence than to spend money trying to confirm the presence or absence through surveillance. While it was never optimal to invest solely in surveillance to reduce uncertainty, it was often optimal to combine surveillance with quarantine or control. These mixed strategies, where multiple actions are implemented simultaneously, were more often optimal than for similar decision models where the extent of the infestation is known, suggesting an element of risk spreading. Optimal investments in each action were driven by their estimated efficacy, and the difference in the estimated impact of a localized and widespread invasion. For example, in our case study, it was often optimal to invest solely in control due to the low estimated efficacy of quarantine and the relatively small impact of a localized incursion. Synthesis and applications. Our analysis shows that the cost of reducing uncertainty through surveillance is not always accompanied by an improvement in Management outcomes. By carefully analysing the benefits of surveillance prior to implementation of Invasive Species Management strategies, managers can avoid wasting resources and improve Management outcomes.
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streamlining search and destroy cost effective surveillance for Invasive Species Management
Ecology Letters, 2009Co-Authors: Cindy E. Hauser, Michael A. MccarthyAbstract:Invasive Species surveillance has typically been targeted to where the Species is most likely to occur. However, spatially varying environmental characteristics and land uses may affect more than just the probability of occurrence. Biodiversity or economic value, and the ease of detection and control are also likely to vary. We incorporate these factors into a detection and treatment model of a low-density invader to determine the surveillance strategy that minimizes expected Management costs. Sites with a high probability of invader occurrence and great benefits associated with detection warrant intensive surveillance; however, the optimum investment is a nonlinear function of these factors. Environments where the invader is relatively easy to detect are prioritized for surveillance, although only a moderate investment is necessary to ensure a high probability of detection. Intensive surveillance effort may be allocated to other sites if the probability of occurrence, budget and/or expected benefits is sufficiently high.
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Streamlining ‘search and destroy’: cost‐effective surveillance for Invasive Species Management
Ecology Letters, 2009Co-Authors: Cindy E. Hauser, Michael A. MccarthyAbstract:Invasive Species surveillance has typically been targeted to where the Species is most likely to occur. However, spatially varying environmental characteristics and land uses may affect more than just the probability of occurrence. Biodiversity or economic value, and the ease of detection and control are also likely to vary. We incorporate these factors into a detection and treatment model of a low-density invader to determine the surveillance strategy that minimizes expected Management costs. Sites with a high probability of invader occurrence and great benefits associated with detection warrant intensive surveillance; however, the optimum investment is a nonlinear function of these factors. Environments where the invader is relatively easy to detect are prioritized for surveillance, although only a moderate investment is necessary to ensure a high probability of detection. Intensive surveillance effort may be allocated to other sites if the probability of occurrence, budget and/or expected benefits is sufficiently high.
Amitrajeet A. Batabyal - One of the best experts on this subject based on the ideXlab platform.
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Ship Inspections in Invasive Species Management: Alternate Regimes and Their Properties
Theoretical Economics Letters, 2013Co-Authors: Amitrajeet A. Batabyal, Hamid BeladiAbstract:When it comes to inspections in Invasive Species Management, the literature has shown that there is frequently a tension between economic cost reduction and inspection stringency. As such, we analyze the properties of two probabilistic inspection regimes that are designed to screen arriving ships in a seaport for the presence of one or more deleterious Invasive Species. In the first regime, the seaport inspector screens arriving ships by using fast (less stringent) and slow (more stringent) protocols. In the second regime, the inspector uses a uniformly stringent protocol with stages. We use the theory of continuous time Markov chains (CTMCs) to delineate both inspection regimes. Next, we derive some key long run performance measures associated with each of these two regimes. Finally, we discuss the implications of our analysis for practical Invasive Species Management.
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Introduction to Essays in the Economics of Invasive Species Management
SSRN Electronic Journal, 2012Co-Authors: Amitrajeet A. BatabyalAbstract:We begin by outlining some of the more salient issues in contemporary research on the Management of Invasive Species. Next, we note that even though there is a sizeable literature in both biology and economics on Invasive Species Management, until very recently, there has been a significant dearth of theoretical research in this subject. Given this state of affairs, a key objective of this book is to show how dynamic and stochastic approaches from economics and operations research can be fruitfully used to first model and then analyze a whole host of Invasive Species related problems that also have noteworthy public policy ramifications. This book is concerned with the economics of Invasive Species Management. To this end, we focus attention on the three topics of international trade, inspections, and agriculture. Following this introductory chapter, the next four chapters study the many and varied nexuses between international trade and Invasive Species related problems. The next eight chapters focus on inspections, an important but nonetheless insufficiently studied topic in Invasive Species Management. Finally, the last two chapters dwell on Invasive Species related problems in the context of agriculture.
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A theoretical analysis of random inspections and fines in Invasive Species Management
Economics Bulletin, 2008Co-Authors: Amitrajeet A. Batabyal, Seung Jick YooAbstract:In this paper, we conduct a theoretical analysis of inspections in a stochastic environment and we shed light on two hitherto unstudied issues concerning inspections in the context of Invasive Species Management. First, given a particular port of entry in a country, we study the properties of a random inspection scheme. Second, we compute the average total fines that will be collected in the long run by an inspection agency that uses the above inspection scheme to screen arriving ships for the presence of one or more Invasive Species.
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International aspects of Invasive Species Management: a research agenda
SSRN Electronic Journal, 2006Co-Authors: Amitrajeet A. BatabyalAbstract:We propose a research agenda for studying six basic questions about the impacts of alternate international Invasive Species control mechanisms on economic agents in a nation such as the USA. The six questions are as follows. First, when can one justify a trade ban as an effective regulatory policy? Second, what are the properties of control rules that vary by port of entry and whether a shipment is viewed as a routine or as a first-time entry? Third, when should a port manager in the USA use information about the dollar value of the products being transported by ships from two exporting firms and the expected time it takes to inspect ships from these two firms to grant preferential treatment to one or the other firm? Fourth, what are some reasonable measures of the trade related risk from Invasive Species? Fifth, how useful is strategic trade policy as an Invasive Species Management tool? Finally, when analyzing a biological invasion, is it more appropriate to focus on the likelihood of this event or, instead, on the magnitude of the event?
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Some Statistical Properties of a Generic Container Inspection Policy in Invasive Species Management
Ecological Economics, 2006Co-Authors: Amitrajeet A. Batabyal, Seung Jick YooAbstract:In recent times - see Batabyal and Nijkamp (2005) and Batabyal and Lee (2006) - there has been considerable interest in studying container inspection policies as a regulatory tool in Invasive Species Management. In this note, we continue this line of inquiry and first delineate a generic container inspection policy. Next, we derive the generating function for the random number of containers in a seaport when this generic policy is used to inspect containers. Finally, we first compute the mean and the variance of the limiting distribution of the number of containers in the seaport under study and then we discuss three ways in which these two moments might be used to manage Invasive Species effectively.
Cindy E. Hauser - One of the best experts on this subject based on the ideXlab platform.
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Optimal surveillance strategy for Invasive Species Management when surveys stop after detection.
Ecology and Evolution, 2014Co-Authors: Gurutzeta Guillera-arroita, Cindy E. Hauser, Michael A. MccarthyAbstract:Invasive Species are a cause for concern in natural and economic systems and require both monitoring and Management. There is a trade-off between the amount of resources spent on surveying for the Species and conducting early Management of occupied sites, and the resources that are ultimately spent in delayed Management at sites where the Species was present but undetected. Previous work addressed this optimal resource allocation problem assuming that surveys continue despite detection until the initially planned survey effort is consumed. However, a more realistic scenario is often that surveys stop after detection (i.e., follow a “removal” sampling design) and then Management begins. Such an approach will indicate a different optimal survey design and can be expected to be more efficient. We analyze this case and compare the expected efficiency of Invasive Species Management programs under both survey methods. We also evaluate the impact of mis-specifying the type of sampling approach during the program design phase. We derive analytical expressions that optimize resource allocation between monitoring and Management in surveillance programs when surveys stop after detection. We do this under a scenario of unconstrained resources and scenarios where survey budget is constrained. The efficiency of surveillance programs is greater if a “removal survey” design is used, with larger gains obtained when savings from early detection are high, occupancy is high, and survey costs are not much lower than early Management costs at a site. Designing a surveillance program disregarding that surveys stop after detection can result in an efficiency loss. Our results help guide the design of future surveillance programs for Invasive Species. Addressing program design within a decision-theoretic framework can lead to a better use of available resources. We show how Species prevalence, its detectability, and the benefits derived from early detection can be considered.
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streamlining search and destroy cost effective surveillance for Invasive Species Management
Ecology Letters, 2009Co-Authors: Cindy E. Hauser, Michael A. MccarthyAbstract:Invasive Species surveillance has typically been targeted to where the Species is most likely to occur. However, spatially varying environmental characteristics and land uses may affect more than just the probability of occurrence. Biodiversity or economic value, and the ease of detection and control are also likely to vary. We incorporate these factors into a detection and treatment model of a low-density invader to determine the surveillance strategy that minimizes expected Management costs. Sites with a high probability of invader occurrence and great benefits associated with detection warrant intensive surveillance; however, the optimum investment is a nonlinear function of these factors. Environments where the invader is relatively easy to detect are prioritized for surveillance, although only a moderate investment is necessary to ensure a high probability of detection. Intensive surveillance effort may be allocated to other sites if the probability of occurrence, budget and/or expected benefits is sufficiently high.
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Streamlining ‘search and destroy’: cost‐effective surveillance for Invasive Species Management
Ecology Letters, 2009Co-Authors: Cindy E. Hauser, Michael A. MccarthyAbstract:Invasive Species surveillance has typically been targeted to where the Species is most likely to occur. However, spatially varying environmental characteristics and land uses may affect more than just the probability of occurrence. Biodiversity or economic value, and the ease of detection and control are also likely to vary. We incorporate these factors into a detection and treatment model of a low-density invader to determine the surveillance strategy that minimizes expected Management costs. Sites with a high probability of invader occurrence and great benefits associated with detection warrant intensive surveillance; however, the optimum investment is a nonlinear function of these factors. Environments where the invader is relatively easy to detect are prioritized for surveillance, although only a moderate investment is necessary to ensure a high probability of detection. Intensive surveillance effort may be allocated to other sites if the probability of occurrence, budget and/or expected benefits is sufficiently high.
Oscar J. Cacho - One of the best experts on this subject based on the ideXlab platform.
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The contribution of passive surveillance to Invasive Species Management
Biological Invasions, 2017Co-Authors: Susan M. Hester, Oscar J. CachoAbstract:It has been recognised for some time that the community has an important role to play in Invasive-Species Management. Reports from the community about new incursions can lead to significant cost savings when this early detection results in shorter Management programs. Unfortunately there is little to guide Invasive-Species managers on cost-effective ways to elicit and incorporate information from the public in their pest-Management programs. Not all community surveillance is equal: some information from the public about the presence of pests and diseases may arise from chance encounters, other data may be reported by stakeholders from a particular industry or by groups of volunteers organised on the basis of citizen science activities. While the resources, activities and effort required to encourage each type of community surveillance are known to differ, very little is known of the relationships that determine effectiveness, and thus the appropriate level of investment that would be required to encourage a particular level of reporting. In this research we focus on passive surveillance—the most fortuitous type of community surveillance—and review the current knowledge base on measuring its cost and effectiveness. We aim to stimulate the research required to improve our understanding of passive surveillance, and we provide guidance on the type of data that should be collected by agencies to enable this research. This information could then provide us with the ability to design optimal surveillance portfolios that integrate the surveillance opportunities provided by the public to best advantage.
D H Yu - One of the best experts on this subject based on the ideXlab platform.
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spartina invasion in china implications for Invasive Species Management and future research
Weed Research, 2007Co-Authors: Shuqing An, Zifa Deng, Changfang Zhou, Binhe Gu, Hongli Li, Zhongsheng Wang, Lin Chen, D H YuAbstract:Summary Four Species of Spartina (Spartina anglica, S. alterniflora, S. patens and S. cynosuroides) have been introduced to China, but currently only the first three are present and only the first two successfully reproduce on the Chinese coast. Spartina anglica and S. alterniflora were introduced to China from England in 1963 and from the United States in 1979, respectively. Today, S. alterniflora has expanded its coverage to more than 112 000 ha and S. anglica has declined to <50 ha. This is compared with only 260 ha of S. alterniflora and over 36 000 ha of S. anglica in 1985. The fates of Chinese Spartina, with dramatic expansion of S. alterniflora and significant decline of S. anglica, were different from those in other locations throughout the world. Factors affecting the growth of the two naturalized Spartina Species in China include differences in artificial plantation strategy, impacts of tideland reclamation, Species competition ability and genetic diversity. Several methods for Spartina control in China, such as harvesting, herbicide application and freshwater irrigation, have been developed, but more research is needed to verify their effectiveness.
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Spartina invasion in China: implications for Invasive Species Management and future research
Weed Research, 2007Co-Authors: Shuqing An, Zifa Deng, Changfang Zhou, Binhe Gu, Hongli Li, Zhongsheng Wang, Lin Chen, D H YuAbstract:Summary Four Species of Spartina (Spartina anglica, S. alterniflora, S. patens and S. cynosuroides) have been introduced to China, but currently only the first three are present and only the first two successfully reproduce on the Chinese coast. Spartina anglica and S. alterniflora were introduced to China from England in 1963 and from the United States in 1979, respectively. Today, S. alterniflora has expanded its coverage to more than 112 000 ha and S. anglica has declined to
