Knowledge gap and conditional receptivity: why tree and forest professionals underutilize citizen science for quarantine pest detection in France

Technical Summary: Knowledge Gap and Conditional Receptivity in Citizen Science for Biosecurity

Problem Statement
Exotic pests and pathogens pose a critical threat to forest ecosystems, with early detection being essential for effective eradication. While the European Union mandates active surveillance of quarantine species, current regulatory frameworks often fail to detect the majority of biological introductions. A significant barrier is the "siloed" nature of biosecurity, where urban, agricultural, and forest surveillance operate independently despite the fluid movement of pests across these boundaries. Although citizen science platforms offer a potential mechanism to increase surveillance coverage by leveraging the "eyes on the ground," their integration into formal biosecurity remains limited. This study investigates the "knowledge gap" and "conditional receptivity" of tree and forest professionals in France regarding the use of citizen science for detecting regulated pests. Specifically, it examines whether professionals possess adequate knowledge of quarantine species and under what conditions they trust or utilize citizen science data for biosecurity purposes.

Methodology
The study employed a cross-sectional survey conducted in France between May and July 2026.

• Participants: 101 professionals involved in tree and forest management or pest surveillance were surveyed. The sample included "SORE experts" (official plant protection officers involved in the mandatory Surveillance of Regulated and Emerging Organisms) and other professionals (arborists, urban planners, forest managers) who were not part of the official surveillance scheme.
• Model Species: The questionnaire focused on ten focal tree pests and pathogens with varying regulatory statuses under EU legislation (Annex IIA, IIB, and III). These included quarantine species absent from the EU (e.g., Emerald Ash Borer), quarantine species present in the EU (e.g., Asian Longhorn Beetle), and non-quarantine but regulated species (e.g., European Spruce Bark Beetle, Pine Processionary Moth).
• Survey Design: The instrument assessed:
  1. Knowledge of species identity and regulatory status.
  2. Usage patterns of five specific citizen science platforms (e.g., iNaturalist, Silvalert).
  3. Attitudes toward the reliability of citizen science data for detecting specific species, including scenarios involving the Asian Longhorn Beetle and Oak Lace Bug.
• Statistical Analysis: Data were analyzed using R (v4.4.1). Cumulative Link Mixed Models (CLMMs) were used to assess knowledge levels and regulatory status recognition, accounting for respondent ID as a random effect. Ordinary Least Squares (OLS) regression was used to correlate perceived identification difficulty with the likelihood of consulting or reporting on citizen science platforms.

Key Results

• Knowledge Disparities: SORE experts demonstrated consistent knowledge across all tested species. In contrast, non-expert professionals showed variable knowledge, significantly higher for widely distributed, non-quarantine pests (Annex III) and lower for quarantine species, particularly those absent from the EU (Annex IIA). Non-experts also struggled to correctly identify the regulatory status of species, often misclassifying non-quarantine species as regulated or vice versa.
• Platform Usage Patterns: 47 out of 101 respondents declared having used citizen science platforms (either those listed or others). Usage was predominantly for consulting species distribution and aiding identification rather than contributing observations. Only 25% of users reported uploading data to these platforms. iNaturalist was the most frequently used platform, utilized twice as often by SORE experts as by other professionals.
• Conditional Receptivity: Professionals' willingness to use citizen science data was highly conditional on the perceived ease of identifying the target species.
  • There was a strong positive correlation between the perceived ease of identifying a pest and the probability that professionals would consult citizen science platforms for information on its distribution.
  • Similarly, the belief that citizen scientists would report observations was higher for easily identifiable species.
  • Professionals expressed greater confidence in citizen science for monitoring established pests (e.g., Oak Lace Bug) than for the early detection of quarantine species (e.g., Asian Longhorn Beetle), even when the latter are large and conspicuous.
• Scenario Responses: In hypothetical scenarios, while respondents generally agreed that citizen science could aid surveillance, they were skeptical about its ability to provide reliable data on species absence or abundance, viewing it primarily as a tool for confirming presence and distribution.

Key Contributions

• Empirical Evidence of the "One-Way" Usage Gap: The study documents that while professionals value citizen science as an information source, they do not currently integrate it as a mechanism for sharing field observations. This creates a bottleneck where professionals consume data but do not feed it back into the system, limiting the platform's utility for early detection.
• Differentiation of Knowledge Gaps: The research highlights that knowledge gaps are not uniform; they are stratified by professional role (expert vs. non-expert) and species status (quarantine vs. non-quarantine). Non-experts, who are often the first to encounter pests in urban or peri-urban settings, lack specific knowledge of quarantine regulations.
• Identification of Receptivity Drivers: The study identifies "conspicuousness" and "ease of identification" as primary drivers of professional receptivity to citizen science, suggesting that the utility of these platforms is perceived as species-specific rather than universal.

Significance and Claims
The paper concludes that citizen science platforms are known and valued by tree and forest professionals in France but remain underutilized as active surveillance tools. The authors claim that:

1. Potential exists but is unrealized: The fact that professionals use these platforms to consult data indicates a foundation of trust that could be leveraged for early detection if workflows were adjusted to encourage data contribution.
2. Biosecurity requires behavioral change: Integrating citizen science into routine biosecurity protocols requires more than just technology; it necessitates cultural shifts and changes in professional workflows to bridge the gap between observation and reporting.
3. Limitations of current integration: Without further methodological and operational developments, citizen science cannot yet be considered a routine tool for the early detection of quarantine pests in France. The current reliance on "consultation only" slows the diffusion of risk awareness and limits the potential for rapid response to new invasions.

The authors maintain a modest tone, acknowledging that their sample size was limited (particularly regarding forest sector representation) and that their findings reflect current ambivalent attitudes rather than definitive barriers. They suggest that future efforts should focus on understanding the specific workflow and cultural barriers preventing professionals from contributing data to these platforms.