Managing biological invasions: the cost of inaction

Abstract

Ecological and socioeconomic impacts from biological invasions are rapidly escalating worldwide. While effective management underpins impact mitigation, such actions are often delayed, insufficient or entirely absent. Presently, management delays emanate from a lack of monetary rationale to invest at early invasion stages, which precludes effective prevention and eradication. Here, we provide such rationale by developing a conceptual model to quantify the cost of inaction, i.e., the additional expenditure due to delayed management, under varying time delays and management efficiencies. Further, we apply the model to management and damage cost data from a relatively data-rich genus (Aedes mosquitoes). Our model demonstrates that rapid management interventions following invasion drastically minimise costs. We also identify key points in time that differentiate among scenarios of timely, delayed and severely delayed management intervention. Any management action during the severely delayed phase results in substantial losses $$( > 50\%$$ ( > 50 % of the potential maximum loss). For Aedes spp., we estimate that the existing management delay of 55 years led to an additional total cost of approximately $ 4.57 billion (14% of the maximum cost), compared to a scenario with management action only seven years prior (< 1% of the maximum cost). Moreover, we estimate that in the absence of management action, long-term losses would have accumulated to US$ 32.31 billion, or more than seven times the observed inaction cost. These results highlight the need for more timely management of invasive alien species—either pre-invasion, or as soon as possible after detection—by demonstrating how early investments rapidly reduce long-term economic impacts.

Economic costs of invasive alien ants worldwide

“…Information on economic costs incurred due to invasive ants, both management costs and damage loss, is critically needed as it aids cost-benefit analysis to determine timely management actions (Ahmed et al 2022). Here, we have shown that incurred costs (costs that have been directly measured) constituted less than 22% of the total costs reported for invasive ants worldwide.…”

Economic costs of invasive bivalves in freshwater ecosystems

“…Nonetheless, the monetary costs reported in this study are still very high (e.g., over $ 1.5 billion per year) and should provide added incentive to manage invasive bivalves in freshwater systems. In this regard, Ahmed et al (2022) demonstrated how timely investments into early management of invasive species rapidly reduce long-term economic impacts, whereas delayed investments-especially in pre-invasion management-increase the costs ultimately incurred via post-invasion management and damage (Cuthbert et al, 2022). Therefore, the fact that management spending is a fraction of damages incurred suggests that not enough is being invested, and particularly in proactive biosecurity measures pre-invasion to prevent secondary spread, as well as in the few measures to rapidly eradicate populations at early invasion stages (e.g., Tang & Aldridge, 2019).…”

Building a synthesis of economic costs of biological invasions in New Zealand

“…Particularly, impacts from invasions can encompass resource damages and losses ( Paini et al, 2016 ), proactive and reactive spending on various forms of management to prevent, control and eradicate invaders ( Robertson et al, 2020 ), and less direct environmental impacts that adversely affect, for example, tourism and recreational activities ( Hanley & Roberts, 2019 ). For management interventions, expenditure in preventative biosecurity measures for invasions can be more cost efficient than longer term management ( Leung et al, 2002 ; Ahmed et al, 2022 ) and can help to negate future damages. However, most national economies, i.e.…”

“…While expensive ( e.g. , averaging $485 million NZD per year from 2017–2020; New Zealand Government, 2019 ), these protocols are implemented with the intention of avoiding greater future costs associated with established IAS management and damages ( Leung et al, 2002 ; Ahmed et al, 2022 ). This is in contrast to the vast majority of countries globally where a blacklisting approach ( i.e.…”

“…While limitations remain, as awareness and uptake of this platform increases, it will be invaluable to IAS research. For example, a lack of easily accessible damage costs can impede efficient allocation of targeted management across species or habitats ( Ahmed et al, 2022 ). Using data available from the InvaCost database, we summarised and described reported economic costs of invasions in New Zealand across approximately the last fifty years.…”