Six Expert-Backed Practices Could Transform How the World Tracks Invasive Species

Biological invasions are no longer a niche concern for ecologists. More than 3,500 species worldwide are recognised as invasive alien species, capable of reshaping ecosystems, degrading the services nature provides, threatening plant and animal health and undermining human wellbeing. The global economic toll is estimated at roughly 400 billion euros every year, a figure comparable to the damage caused by major earthquakes and wildfires, and it is expected to keep climbing. Against this backdrop, a team of Italian researchers has done something unusually practical: instead of simply documenting the problem, they asked ninety of their colleagues how the science of invasion biology itself could be done better, and then rigorously tested the answers they received.

The study, published in the journal NeoBiota, brought together experts working across terrestrial, freshwater and marine ecosystems in Italy, one of Europe’s most biodiverse countries and a recognised hotspot for biological invasions. According to the Italian Institute for Environmental Protection and Research, nearly 3,800 non-indigenous species have been recorded in the country, of which 3,659 are currently established, with significant ecological consequences and negative impacts on agriculture, forestry, fisheries and aquaculture. Yet the data needed to manage this complex issue are often fragmented across research groups and infrastructures, difficult to access or reuse, and rarely communicated to the wider public. The researchers set out to close that gap with a structured, expert-driven methodology spanning four steps.

The workflow began between July and November 2022, when the team engaged ninety experts specialising in the taxonomy, biology, ecology, monitoring and management of non-indigenous species. Participants were identified through reviews of existing Italian studies, involvement in major conservation projects and a snowball approach in which experts recommended additional colleagues. All completed an online questionnaire composed primarily of open-ended questions, designed to map key research efforts, identify the most frequently studied species, compile ongoing projects and monitoring activities, and expose major gaps in current research. From the survey results, the team distilled an initial set of nine potential good practices aimed at standardising how data on biological invasions are collected, shared and communicated.

Those nine candidates were then discussed and refined through a consensus-based analysis, ultimately consolidating into six practices that form an acronym the authors call TRACKS. The letters stand for Tracking non-indigenous species in biodiversity data collections; Reference protocols for data collection; Active participation; Collaboration and FAIR principles; Knowledge hub for data; and Strategic communication. Each practice was then dissected through a SWOT analysis, a structured decision-making framework that examines internal strengths and weaknesses alongside external opportunities and threats. Although SWOT is widely applied in business and conservation planning, it has rarely been used to evaluate research practices, making this application a methodological novelty in invasion science.

The quantitative evaluation involved eighty-nine researchers, categorised by expertise: thirty-three working on terrestrial invasions, twenty-eight on marine and twenty-eight on freshwater. Each participant scored the strengths, weaknesses, opportunities and threats of every practice on a seven-point scale. The team then aggregated the scores into two composite measures per practice, subtracting weakness scores from strength scores and threat scores from opportunity scores, producing a bipolar scale ranging from minus seven to plus seven. Cross-plots revealed good agreement among experts from all three domains, and a cluster analysis using the Partitioning Around Medoids method identified two groups of experts whose differences were mainly confined to how strongly they endorsed a centralised data repository and risk communication. A Kruskal-Wallis test found no significant differences in scores between the three ecosystem-focused groups, suggesting the practices resonate across disciplinary boundaries.

The first practice, tracking non-indigenous species in biodiversity data collections, asks every research group collecting species abundance or distribution data to verify and report the presence of non-indigenous species, ensuring correct identification at the lowest taxonomic level. Experts rated it highly on strengths and opportunities, reflecting growing scientific and policy interest in invasion monitoring. But a critical barrier emerged: the progressive shortage of trained taxonomists, a problem shared across conservation science worldwide and potentially exacerbated in Italy by long-standing cuts to public research funding. The authors argue that stronger collaboration among research institutions, dedicated training courses, workshops and the emerging field of DNA barcoding will be essential to prevent misidentification and build large-scale distribution maps.

The second practice calls for adherence to established protocols when collecting data, supported by a national repository of reference protocols. Italy has already developed monitoring protocols for more than 300 taxa through collaboration among scientific societies and national experts, though these were primarily designed for native species and do not cover the full spectrum of invaders. The researchers highlight the need to update protocols, standardise them across taxonomic groups and make them accessible to stakeholders with varying levels of expertise. Particular attention should go to introduction gateways such as ports, airports, nurseries, garden centres and aquaculture facilities, where early detection is most feasible, building on approaches already embedded in European marine and aquaculture regulations.

The remaining practices address participation, data sharing and public engagement. Citizen science and local ecological knowledge can dramatically expand the spatial and temporal coverage of monitoring; a recent European comparison found that citizen science platforms reported new non-indigenous species earlier than official databases in twenty percent of cases and within the same year in another thirty percent. However, these approaches tend to under-represent small or inconspicuous species and require robust validation to avoid contaminating datasets with misidentified records. On the data side, the fourth practice urges adoption of FAIR principles, making data findable, accessible, interoperable and reusable, and received the highest opportunity score of all six. The authors stress that newly recorded species should be reported immediately rather than waiting for formal publication, since delays reduce the likelihood of successful eradication and increase costs. The fifth practice proposes an open-access knowledge hub to consolidate fragmented national data, while the sixth promotes strategic communication, warning that overly alarmist messaging or politicisation of invasion science can backfire and discourage public engagement.

The study’s conclusions carry weight beyond Italy. Because the ninety experts operated across highly diverse contexts, taxa, habitats and methodological approaches, the resulting practices function as general guidelines rather than prescriptions tied to a single ecosystem or taxonomic group. They are not meant to replace existing tailored guidelines but to support all research groups collecting biodiversity data, including those whose primary focus lies elsewhere but whose work could nonetheless yield valuable information on invader occurrence, abundance and distribution. The authors hope the synthesis will stimulate broader debate, foster methodological harmonisation and strengthen integration among specialists ranging from taxonomists and fisheries biologists to veterinarians, agricultural entomologists and public health experts, ultimately bridging the cultural and operational divide between terrestrial and aquatic systems and reinforcing collective capacity to respond to rapidly changing ecosystems.

Subject of Research: Expert-based identification and SWOT evaluation of six good practices for improving research on non-indigenous species across terrestrial, freshwater and marine ecosystems

Article Title: TRACKS: Six good practices for Non-Indigenous Species research and their SWOT evaluation

Article References: Azzurro, E., Strafella, P., Bertolino, S., Carnevali, L., Crocetta, F., Di Muri, C., Genovesi, P., Monaco, A., Rosati, I., Tricarico, E., Anfora, G., Ardenghi, N. M. G., Badalamenti, E., Badalamenti, F., Balestrieri, R., Bernardo, U., Boggero, A., Bolognini, L., Bolpagni, R., … Cerri, J. (2026). TRACKS: Six good practices for Non-Indigenous Species research and their SWOT evaluation. NeoBiota, 105, 229-257. https://doi.org/10.3897/neobiota.105.171461

Image Credits: AI Generated

DOI: 10.3897/neobiota.105.171461

Keywords: non-indigenous species, invasive alien species, biological invasions, SWOT analysis, citizen science, FAIR principles, biodiversity monitoring, taxonomic expertise, open science, data sharing, ecosystem management, Italy