Modelling the damage costs of invasive alien species

Abstract

The rate of biological invasions is growing unprecedentedly, threatening ecological and socioeconomic systems worldwide. Quantitative understandings of invasion temporal trajectories are essential to discern current and future economic impacts of invaders, and then to inform future management strategies. Here, we examine the temporal trends of cumulative invasion costs by developing and testing a novel mathematical model with a population dynamical approach based on logistic growth. This model characterises temporal cost developments into four curve types (I - IV), each with distinct mathematical and qualitative properties, allowing for the parameterization of maximum cumulative costs, carrying capacities and growth rates. We test our model using damage cost data for eight genera (Rattus, Aedes, Canis, Oryctolagus, Sturnus, Ceratitis, Sus and Lymantria) extracted from the InvaCost database – which is the most up-to-date and comprehensive global compilation of economic cost estimates associated with invasive alien species. We find fundamental differences in the temporal dynamics of damage costs among genera, indicating they depend on invasion duration, species ecology and impacted sectors of economic activity. The fitted cost curves indicate a lack of broadscale support for saturation between invader density and impact, including for Canis, Oryctolagus and Lymantria, whereby costs continue to increase with no sign of saturation. For other taxa, predicted saturations may arise from data availability issues resulting from an underreporting of costs in many invaded regions. Overall, this population dynamical approach can produce cost trajectories for additional existing and emerging species, and can estimate the ecological parameters governing the linkage between population dynamics and cost dynamics.

Economic costs of invasive bivalves in freshwater ecosystems

“…However, while categorizations for invader socio‐economic impacts have been designed (Bacher et al, 2017), there remains a paucity of quantified socio‐economic costs for key taxonomic groups, hampering effective cost–benefit analysis and rationale for policymakers to invest the sparse available resources towards prevention and control (but see Cuthbert, Pattison, et al, 2021; Diagne et al, 2021, for analyses at the global scale across taxa). This constraint to invest still exists even though it has been shown that preventive measures are generally considered more cost‐effective than long‐term damages and control (Ahmed et al, 2021; Keller et al, 2008), with pre‐invasion management remaining underfunded (Leung et al, 2002). Indeed, proactive preventative measures have the potential to yield trillion‐dollar savings over just a few decades compared with delayed management actions (Cuthbert et al, 2022).…”

Invasion impacts and dynamics of a European‐wide introduced species

“…The relationship in (a) displays the implications (in economic cost of control efforts) of a generalized invasive species' population dynamics over time, after its introduction and establishment in a new environment. As the population spreads, both the area invaded (as a percentage of the total available area, which commonly reflects the invader's abundance) and its management costs increase following a S‐shaped curve as adapted from Department of Primary Industries (2015) and Ahmed et al (2021). (b) The proposed “impact curve” describes the impact exerted on an invaded area associated with the cumulative abundance of an invasive population within that area.…”

“…In the final saturation stage, population sizes may naturally fluctuate around the asymptote (Geburzi & McCarthy, 2018). This curve, albeit largely theoretical, has been used to quantify ecological effects and related to economic costs of invasive species (Ahmed et al, 2021).…”