Approaches for estimating benefits and costs of interventions in plant biosecurity across invasion phases

Abstract

Nonnative plant pests cause billions of dollars in damages. It is critical to prevent or reduce these losses by intervening at various stages of the invasion process, including pathway risk management (to prevent pest arrival), surveillance and eradication (to counter establishment), and management of established pests (to limit damages). Quantifying benefits and costs of these interventions is important to justify and prioritize investments and to inform biosecurity policy. However, approaches for these estimations differ in (1) the assumed relationship between supply, demand, and prices, and (2) the ability to assess different types of direct and indirect costs at invasion stages, for a given arrival or establishment probability. Here we review economic approaches available to estimate benefits and costs of biosecurity interventions to inform the appropriate selection of approaches. In doing so, we complement previous studies and reviews on estimates of damages from invasive species by considering the influence of economic and methodological assumptions. Cost accounting is suitable for rapid decisions, specific impacts, and simple methodological assumptions but fails to account for feedbacks, such as market adjustments, and may overestimate long-term economic impacts. Partial equilibrium models consider changes in consumer and producer surplus due to pest impacts or interventions and can account for feedbacks in affected sectors but require specialized economic models, comprehensive data sets, and estimates of commodity supply and demand curves. More intensive computable general equilibrium models can account for feedbacks across entire economies, including capital and labor, and linkages among these. The two major considerations in choosing an approach are (1) the goals of the analysis (e.g., consideration of a single pest or intervention with a limited range of impacts vs. multiple interventions, pests or sectors), and (2) the resources available for analysis such as knowledge, budget and time.

Optimizing management of invasions in an uncertain world using dynamic spatial models

“…Each damage or control cost is defined as the cost per unit of density, abundance, or presence of invaders (Olson & Roy, 2008). Uncertainty in the occupancy or abundance of the target species can compound uncertainty in these costs (Welsh et al, 2021). The typical management cost function assumes that it becomes increasingly costly to locate and remove the remaining individuals as density/abundance decreases (Fischer et al, 2020; Olson & Roy, 2008).…”

Bactrocera dorsalis in the Indian Ocean: A tale of two invasions

“…In response to globalization, there has been an increased concern surrounding invasive phytophagous insect species, which is motivated by the accumulating economic losses in the fruit trade (Suckling et al, 2013 ; Welsh et al, 2021 ). The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is a major pest species natively found in wet tropical regions of Asia (Clarke et al, 2019 ; Zeng et al, 2019 ).…”

“…Range expansions of B. dorsalis are fairly well documented, but little research has been done on the genetic nature of migration pathways of B. dorsalis on a regional scale (Garzón‐Orduña et al, 2019 ; Zeng et al, 2019 ). Especially information on human‐mediated range expansions, which can be complex in nature (e.g., colonization of oceanic islands) is generally lacking and could provide new information beneficial to sanitary protocols such as improved quarantine systems and better detection and screening methods (Kim et al, 2021 ; Suckling et al, 2013 ; Welsh et al, 2021 ). One example of human‐mediated range expansion is the spread of B. dorsalis throughout islands in the Indian Ocean.…”

Value‐adding in biosecurity surveillance and monitoring: Testing colour and non‐target semiochemical lures on Psylloidea and Pentatomoidea

“…Invasive species are an escalating threat to countries due to increased global travel, free trade agreements and open markets (Cope et al, 2019; Meurisse et al, 2019), resulting in increased costs associated with biosecurity surveillance. This has resulted in an uptick in studies of economic optimisation and efficiencies in biosecurity surveillance recently (e.g., Barnes et al, 2020; Welsh et al, 2021). Accumulation rates of introduced taxa are not slowing (Seebens et al, 2017), suggesting current pathway management controls are only partially effective for importing countries in many regions (Meurisse et al, 2019).…”

“…This tool provides more impetus to jurisdictions to conduct cost‐effective and statistically sound surveillance for plant pests. Given the cost of surveillance, the rigour required (Welsh et al, 2021), and the increasing numbers of invasive pests able to exploit global movement (Tobin et al, 2014), opportunities to increase the surveillance ‘bang for the buck’ should be embraced. Examples of such opportunities include optimising efforts in high‐risk pathways (Jamieson et al, 2022) and value‐adding to surveillance efforts by targeting more than one pest species at each trapping site (e.g., Marchioro et al, 2020; Stringer et al, 2019).…”