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

Abstract

Biological invasions are a major component of anthropogenic environmental change, incurring substantial economic costs across all sectors of society and ecosystems. However, the economic costs of invasions have been disparately reported, lacking synthesis across taxonomic and sectorial scales. Using the newly compiled InvaCost database, we analyse reported economic damage and management costs incurred by biological invasions in New Zealand — a country renowned for its approaches to invasive species management — from 1968 to 2020. In total, US$69 billion (NZ$97 billion) is currently reported over this ~50 year period, with approximately US$9 billion of this considered highly reliable, observed (c.f. projected) costs. Most (82%) of these observed economic costs are associated with damage, with comparatively little invested in management (18%). Reported costs are increasing over time, with damage averaging US$120 million per year and exceeding management expenditure in all decades. Where specified, most reported costs are from terrestrial plants and animals, with damages most often borne by primary industries such as agriculture and forestry. Management costs are associated more with interventions by authorities and stakeholders. However, some known ecologically (c.f. economically) impactful invasive species are notably absent from estimated damage costs, and management costs are not reported for a number of game animals and agricultural pathogens. Given these gaps for known and potentially damaging invaders, we urge improved cost reporting at the national scale, including improving public accessibility through increased access and digitisation of records, particularly in overlooked socioeconomic sectors and habitats. This also further highlights the importance of investment in management to curtail future damages across all sectors.

The wild cost of invasive feral animals worldwide

“…These ecological and socioeconomic impacts are particularly notable in insular habitats (Whittaker & Fernández-Palacios, 2007;Bellard et al, 2017;Bodey et al, 2022), with cats in particular driving population declines and extinctions of endemic vertebrates on more than 100 islands worldwide (Medina et al, 2011(Medina et al, , 2014. While the impacts of cats-particularly colonies of stray cats-are massive and particularly severe on islands, obtaining reliable data on the ecological and economic impacts in mainlands is more challenging due to the complexities involved in monitoring and quantifying their effects in these environments (Trouwborst et al, 2020;Carrete et al, 2022).…”